Effects of curcumin analogue L6H4 on myocardial tissue of type 2 diabetic rats

AIM: To explore the effects of curcumin analogue L6H4 on the myocardial tissue of type 2 diabetic rats and its mechanism. METHODS: Male Sprague-Dawley rats were randomly divided into normal control (NC) group, high-fat (HF) group, high-fat treatment (FT) group, diabetes mellitus (DM) group and diabetes treatment (DT) group.The rats in the latter 4 groups were fed high-fat diet for 4 weeks, then the rats in DM groups and DT groups were intraperitoneally injected with streptozotocin (STZ) to induce type 2 diabetes, while the rats in FT group and DT group were given L6H4. The blood glucose and lipid levels were detected by biochemical method, and serum adiponectin (APN) levels were detected by ELISA. The serum insulin levels were measured by radioimmunoassay and homeostasis model assessment of insulin resistance (HOMA-IR) were calculated. The morphological changes of myocardium were observed by Masson staining and electron microscopy. The protein expression of adiponectin receptor 1 (AdipoR1) and transforming growth factor β1(TGF-β1) in myocardial tissue were determined by immunohistochemistry. The protein expression of adipoR1 was also detected by Western blot for verification. RESULTS: Compared with NC group, the blood glucose, lipids, insulin, HOMA-IR and TGF-β1 were increased in HF and DM group, but they were decreased after treated with L6H4. Compared with NC group, the concentration of serum APN were decreased and the expression of AdipoR1 in the myocardium were weakened in HF group and DM group, and they increased after treated with L6H4. The myocardial fibrosis was obvious in HF group and DM group, the mitochondria in cardiomyocytes expanded, and the cristae disordered, partial disappeared. These lesions were significantly reduced after L6H4 treatment. CONCLUSION: L6H4 exerts a protective effect on the heart in type 2 diabetic rats. The increased concentration of serum APN, the enhanced expression of AdipoR1, and the expression of TGF-β1 inhibited by APN may be involved in the mechanism of protection.     

Influence of Tangshenfang on diabetic liver injury and the expression of SIRT1 and PGC-1α in the liver tissue

AIM: To observe the effect of Tangshenfang (TS) on the liver protection and the levels of silent information regulator 1 (SIRT1) and peroxisom proliferator-activated receptor γ coactivator-1α (PGC-1α) in the liver tissue. METHODS: The rat model of diabetes mellitus (DM) was established by intravenous injection of streptozotocin (STZ;30 mg/kg) after having the high fat/high glucose diets for 1 month. The diabetic rats were randomly divided into DM group, DM with high-dose TS (TS^Hi) group, medium-dose TS (TS^Med) group and low-dose TS (TS^Low)group. The normal rats were served as control group. There were 8 rats in each group. After treatment with TS for 12 weeks, the serum biochemical indices including fasting blood glucose (FBG), triglyceride (TG), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were tested. Fasting insulin (FINS) was also detected by radioimmunoassay, and homeostatic model assessment for insulin resistance (HOMA-IR) was calculated. The serum levels of tumor necrosis factor-α (TNF-α) and interleukin-1 (IL-1) were measured by ELISA. The activity of SOD and content of MDA in the liver tissues were measured by the methods of hydroxylamine and thiobarbituric acid. The liver pathological changes were observed under light microscope with HE and Masson staining. The protein expression of SIRT1and PGC-1α in the liver tissues was determined by Western blot. RESULTS: In DM group, serum FBG, TG, ALT, AST, FINS, HOMA-IR, TNF-α and IL-1 were obviously increased compared with the control group (P<0.01). The fatty changes, local necrosis, inflammation and fibrosis in the liver tissues were observed. The content of MDA in liver increased, while the activity of SOD decreased markedly. The protein expression of SIRT1 and PGC-1α was decreased (P<0.05). In TS treatment groups, all these changes in DM rats were markedly reversed by TS, and the protein expression of SIRT1 and PGC-1α in the liver tissues was markedly increased. CONCLUSION: TS may protect the rats from diabetic liver injury by increasing the expression of SIRT1 and PGC-1α, and thereby improving insulin resistance and oxidative stress.     

Influence of 8-week swimming on peripheral neuropathy in type 2 diabetic rats

AIM: To explore the influence of long-term swimming on peripheral neuropathy in type 2 diabetic rats. METHODS: Male Wistar rats were fed with a high-fat and high-fructose diet, and injected with streptozocin to establish a model of type 2 diabetes mellitus. The rats were randomly divided into 4 groups: blank control group (C group), exercise control group (CE group), diabetes mellitus group (DM group) and diabetes mellitus+exercise group (DME group). The rats in CE group and DME group received 8-week swimming training (6 d/week). The training time was 20, 30 and 45 min in the first 3 d,respectively, and then it increased to 60 min a day. Eight weeks later, the motor nerve conduction velocity (MNCV) and the levels of tumor necrosis factor α (TNF-α), interleukin 6 (IL-6) and C-reactive protein (CRP) in sciatic nerve tissues of the rats were measured. The morphological changes of the sciatic nerve were also observed under light microscope. RESULTS: Compared with DM group, 8-week swimming obviously accelerated the MNCV (P<0.05), decreased the levels of TNF-α, IL-6 and CRP in DME group (but no significant difference, P>0.05). The obvious nerve injury in DM group was observed. However, the pathological change of the sciatic nerve in DME group was relieved. CONCLUSION: Eight-week swimming training significantly accelerates the MNCV, attenuates the nerve injury in diabetic rats and has protective effect on peripheral nerve, which may be correlated with relieving the inflammatory reaction.     

Effects of pyrrolidine dithiocarbamate on synthesis of hepatic glycogen in diabetic rats

AIM: To determine the effect of pyrrolidine dithiocarbamate on hepatic glycogen synthesis and its mechanism in diabetic rats. METHODS: Male Wistar rats were randomly divided into normal diet group and high-fat diet group. After 8 weeks of feeding, the rats in high-fat diet group were injected intraperitoneally with a single dose of streptozotocin (27 mg/kg) to induce type 2 diabetes. The diabetes rats were randomly divided into 3 groups: diabetes mellitus group (DM), PDTC-treated group (DM+PDTC) and insulin-treated group (DM+INS). The rats in PDTC-treated group were injected with PDTC (50 mg/kg) intraperitoneally daily. At the same time, the rats in normal diet group, DM group and insulin-treated group were injected with equivalent volume of saline in the same way. The rats in insulin-treated group were injected with insulin (1 U/kg) 1 h before killed. After the treatment was taken for 1 week, the levels of blood glucose were measured, then the animals in all groups were killed. The liver glycogen content was detected, and the levels of GSK-3β and Akt phosphorylation in the liver tissues were analyzed by Western blotting. RESULTS: The blood glucose level and liver glycogen content were significantly higher, and the levels of GSK-3β and Akt phosphorylation were lower in DM group than those in normal-diet group (P<0.01). Compared with DM group, the glycogen content, the phosphorylation of Akt and GSK-3β in the liver tissues in DM+PDTC group and DM+INS group increased significantly (P<0.01), and the blood glucose levels decreased (P<0.01). CONCLUSION: PDTC increases the synthesis of liver glycogen and decreases the level of blood glucose by regulating the activity of Akt and GSK-3β in the liver.     

Effect of curcumin derivative B06 Bob on synthesis of testosterone from type 2 diabetic rats

AIM: To investigate the effect of curcumin derivatives B06(B06) on the synthesis of testosterone from type 2 diabetic rats. METHODS: Male Sprague-Dawley rats were evenly divided into 5 groups randomly: normal control group (C group), high fat group (H group), high fat treatment group (HT group), diabetes mellitus group (D group) and diabetes treatment group (DT group). The rats in the later 4 groups were fed with high fat diet, after 4 weeks of high fat diet feeding, the rats from D group and DT group were injected with low dose of streptozotocin intraperitoneally to induce diabetes mellitus, while the rats in HT group and DT group were gavaged with B06 at the dose of 0.2 mg·kg^-1·d^-1 for 8 weeks. The blood glucose was detected by glucometer, blood insulin was assayed by ELISA and the insulin resistance index was calculated. The morphology of testes were observed by light and transmission electron microscopy. Serum testosterone and estradiol were measured by radioimmunoassay. The protein expression of steroidogenic acute regulatory protein (StAR) was detected by immunohistochemistry. The mRNA expression of StAR, cholesterol side-chain cleavage enzyme (P450scc), cytochrome P450 17A1 (P450c17), cytochrome P450 aromatizing enzyme (P450arom), 3β-hydroxysteroid dehydrogenase (HSD) and 17β-HSD was detected by RT-PCR. RESULTS: The levels of blood glucose and insulin resistance index were increased in H group and D group, and serum testosterone was decreased, all of which were reversed after the treatment of B06. Testicular seminiferous tubule was distorted, spermatogenic cells were dropped in H group and D group. In addition, leydig cells were found to have swelling mitochondria in H group and D group, endoplasmic reticulum was reduced, and there was karyopyknosis accompany with sparse chromatin, all of which were ameliorated by B06. The protein expression of StAR was decreased in D group. The mRNA expression of StAR and P450scc was decreased in H group and D group, all of which were increased in B06 treatment group. There was no significant difference in the mRNA expression of P450c17, P450arom, 3β-HSD and 17β-HSD. CONCLUSION: B06 may increase serum testosterone and relieve the damage of testes from type 2 diabetic rats. B06 improves metabolic disorder by up-regulating mRNA expression of StAR and P450scc.     

Effects of resveratrol on cardiac dysfunction and ASMase-ceramide pathway in type 2 diabetic rats

AIM:To investigate the effects of resveratrol (RSV) on cardiac dysfunction and acid sphingomyelinase (ASMase)-ceramide pathway in diabetic rats. METHODS:Type 2 diabetes mellitus (T2DM) model was established by a high-fat diet combined with STZ intraperitoneac injection (30 mg/kg). SD rats (n=20) were randomly divided into control group, T2DM group; T2DM+RSV group (diabetic rats were given resveratrol at 100 mg·kg·d^-1 by intragastric administration for the treatment) and RSV group (some of control rats were selected to give the same dose of RSV for drug control group). The M-mode Doppler ultrasonography was performed to observe the changes of cardiac function and structure in the rats. The levels of serum glucose, lipid and superoxide dismutase (SOD) activity, malondialdehyde (MDA) content in heart tissues were measured. Oil red O staining and Sirius red staining were performed to observe lipid accumulation and cardiac fibrosis in heart tissues. The cardiac ceramide concentration in diabetic rats was analyzed by high-performance liquid chromatography. The protein expression of ASMase and peroxisome proliferator-activated receptor-γ co-activator 1α (PGC-1α) in the hearts was determined by Western blot. RESULTS:Compared with the control group, the levels of fasting blood glucose, total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) were significantly elevated in T2DM group. The values of ±dp/dt_max, fractional shortening and ejection fraction were declined, and the left ventricle internal dimension at end-systole (LVIDs) and left ventricle internal at end-diastole (LVIDd) were increased. Furthermore, increased MDA content and more lipid accumulation were also observed in diabetic hearts, while the SOD activity, ATP content and PGC-1α expression were reduced in diabetic hearts. However, all these parameters were reversed by addition of RSV, concomitant with decreased ASMase expression and ceramide content. CONCLUSION:RSV dramatically alleviates diabetes-induced cardiac dysfunction and cardiac fibrosis, which may attribute to inhibition of ASMase-ceramide activation.     

Effects of extract of gingko biloba on expression of glucocorticoid receptor in hepatic tissues from type 2 diabetic rats

AIM: To study the effect and mechanism of extract of ginkgo biloba (EGB) on liver glucocorticoid receptor (GR) expression in type 2 diabetic rats. METHODS: Thirty male Sprague-Dawley rats were divided randomly into three groups: normal control group (n=10), type 2 diabetic group (n=10) and ginkgo biloba treated group (n=10). After fed with high-fat feeding for 4 weeks, the later two groups were injected with streptozotocin at a dose of 30 mg/kg intraperitoneally to induce type 2 diabetic rat model. The EGB treated group was gavaged with EGB at the dose of 50 mg·kg-1·d-1 for 12 weeks. At the end of experiment, the rats were sacrificed, the blood glucose, serum lipid and blood insulin were measured. The morphology of liver tissue was observed under light microscopy with HE staining. GR mRNA expression in liver was measured by RT-PCR. The level of GR protein expression in liver tissue was detected by immunohistochemistry. RESULTS: EGB reduced the levels of blood glucose, blood lipids, blood insulin in diabetic rats. EGB also relieved fatty degeneration and necrosis of the hepatic cells, ameliorated infiltration of inflammatory cells in the liver; and decreased GR expression at both mRNA and protein levels in diabetic liver. CONCLUSION: EGB may inhibit GR expression in liver of type 2 diabetic rats, which results in decreasing the level of blood glucose, blood lipid, blood insulin and relieving the liver damage in type diabetic rats.     

Influence of metformin on LPIN1 expression and AMPK signaling in high-fat diet-induced insulin resistant rats

AIM: To explore the regulatory mechanism of LPIN1 in hepatic insulin resistance by investigating the influence of metformin on the expression of LPIN1 and AMP-activated protein kinase(AMPK) signaling in the rats with high-fat diet-induced insulin resistance. METHODS: Thirty-six 4-week-old male Wistar rats were randomly divided into 2 groups: control group and high-fat diet (HF) group. The rats in HF group were fed with high-fat diet for 8 weeks and then were randomly divided into 2 subgroups: HF group and metformin intervention group, and the animals were continuously raised for 8 months. The mRNA levels of α1 and α2 subunit of AMPK as well as LPIN1 were measured by real-time RT-PCR. Phospho-AMPKα (Thr-172) was detected by Western blotting to evaluate the activity of AMPK. RESULTS: After 4 months, the rats in HF group showed significant increase in the levels of body weight, fast plasma glucose and insulin, and the levels of triglyceride and total cholesterol significantly elevated.Significant decrease in LPIN1 and phospho-AMPKα (Thr-172) expression in the rat livers were also observed. After treated with metformin, the metabolic indexes of the HF rats were improved. The mRNA and protein expression of AMPKα1 and AMPKα2 had no significant difference among the 3 groups. Metformin treatment also increased the expression of LPIN1 in the liver tissues of HF rats. CONCLUSION: The decrease in LPIN1 expression and AMPK activity may contribute to hepatic insulin resistance in diet-induced obese rats. Metformin improves the LPIN1 expression and AMPK activity through the interaction between LPIN1 and AMPK signal pathways.     

Protective effects of Zhenwu decoction on kidney injury of diabetic rats induced by streptozotocin

AIM：To investigate the effects of Zhenwu decoction (ZWD) on the expression of α-smooth muscle actin (α-SMA) and NF-κB in diabetic nephropathy (DN) rats. METHODS：Diabetic rat model was induced by intrape-ritoneal injection of streptozotocin (STZ), and the animals were randomly divided into STZ group (n=22) and STZ+ZWD group (n=23). The normal rats served as control (n=16). All rats were sacrificed on 8 weeks after modeling. Biochemical assay and pathological observation (HE staining and transmission electron microscopy) were used to evaluate the effects of Zhenwu decoction on the renal function and pathological morphology. The body weight, renal index, blood glucose, total urinary protein in 24 h, and superoxide dismutase (SOD), malondialdehyde (MDA),inducible nitric oxide synthase (iNOS) were determined as well. Western blotting was used to observe the effects of Zhenwu decoction on the expression of α-SMA and NF-κB in diabetic nephropathy (DN) rats. RESULTS：Compared with normal group, the renal index, blood glucose concentration, total urinary protein in 24 h, blood urea nitrogen (BUN), serum creatinine (SCr) and MDA were significantly higher and body weight was lower in DN rats (P<0. 05). Pathological examination of the kidneys in DN group showed glomerular hypertrophy, glomerular basement membrane thickening, tubular epithelial cell degeneration, mesangial matrix proliferation, protein cast formation in some renal tubules. The protein expression levels of α-SMA and NF-κB were markedly increased (P<0.05). After ZWD treatment, the level of renal index, total urinary protein in 24 h, BUN, SCr and the expression of α-SMA and NF-κB at the protein level were significantly decreased (P<0.05). The renal histological injury in ZWD group was significantly ameliorated. CONCLUSION：Zhenwu decoction might protect kidney against STZ-induced injury via decreasing the expression of α-SMA and NF-κB.     

Effects of renal denervation on inflammatory factors in a rabbit model of early atherosclerosis

AIM: To evaluate the effects of renal denervation (RDN) on the expression of tumor necrosis factor-α (TNF-α), interleukin-1α (IL-1α) and interleukin-6 (IL-6) in a rabbit model of early atherosclerosis. METHODS: New Zealand male rabbits were divided into control group, RDN+ high-fat diet (HFD) group (RDN group), sham+HFD group (sham group) and HFD group. The rabbits in later 3 groups were fed with 2% cholesterol for 8 weeks to establish an early atherosclerosis model. The blood samples were collected to test the levels of lipids, norepinephrine (NE), TNF-α, IL-1α and IL-6. The protein expression of angiotensin Ⅱ (Ang Ⅱ) was detected by the method of immunohistochemistry. The levels of nuclear factor-κB (NF-κB) and Ang II 1 type receptor (AT1R) were evaluated by Western blot. The mRNA expression of TNF-α, IL-1α and IL-6 was determined by real-time PCR. RESULTS: After 1 d of RDN procedure, the NE level was lower in RDN group than that in sham group (P<0.01). After 8 weeks, the NE level was lower in RDN group than that in sham group and HFD group (P<0.05), and triglyceride (TG) was lower in RDN group than that in HFD group (P<0.05). The protein expression of Ang II was decreased in RDN group compared with sham group and HFD group (P<0.01). The protein expression of NF-κB was lower in RDN group than that in sham group (P<0.05). The plasma levels of TNF-α and IL-1α were reduced in RDN group compared with sham group and HFD group (P<0.05). The mRNA expression of TNF-α, IL-1α and IL-6 was reduced in RDN group compared with sham group (P<0.05). CONCLUSION: RDN inhibits sympathetic activity, decreases the plasma level of TG, and alleviates inflammatory reactions in the rabbits with atherosclerosis.     

Study on relationship between expression of PKCα in glomeruli and development of nephropathy in diabetic rats

AIM:To observe the dynamic changes of expression of PKCα, TGF-β₁ and α-SMA in glomeruli of diabetic rats induced by the alloxon and to invesitigate their roles in the diabetic nephropathy(DN).METHODS:Rats were randomly divided into four groups: normal control group (group A), diabetic group of one week (group B), diabetic group of one month (group C), diabetic group of two months (group D). Immunohistochemistry and Western blotting were used to detect the expression of PKCα, TGF-β₁ and α-SMA in renal tissue of all groups. Blood glucose, triglycerides, cholesterol, creatinine and urine protein were analysed by chemical methods. The morphological changes of renal tissue were checked through microscopy.RESULTS:The expression of PKCα and TGF-β₁ in renal tissue of diabetic groups were increased comparing with those of nomal control group(P<0.05). The mesangial cells expressed α-SMA in two months group. Chronologically the expression of PKCα, TGF-β₁ and α-SMA were positively correlative with each other and the impairment of kidney was also observed.CONCLUSIONS: During the DN process the expression of PKCα increased. PKCα raised GFR and the permeability of glomerular filtration membrane which enhanced urinary albumin excretion. PKCα also increased expression of TGF-β and therefore to induce the expression of α-SMA. The appearance of α-SMA was a marker of the phenotypic transform of renal cells.     

Hypolipemic and hypoglycemic effects of total triterpenoids from Psidium guajava leaves on type 2 diabetic rats

AIM: To investigate the effects of total triterpenoids from Psidium guajava leaves (TTPGL) on blood glucose and lipids in type 2 diabetic rats. METHODS: The diabetic rats were induced by intraperitoneal injection of streptozotocin at dose of 35 mg/kg and feeding with high-fat diet. The animals were divided into 5 groups: diabetic model control group (model), TTPGL treatment groups (with the doses of 60, 120 and 240 mg/kg, respectively) and rosiglitazone treatment group (3 mg/kg). Another 12 normal SD rats were used as the normal controls. The rats received daily treatment for 6 weeks, and then the levels of fasting blood glucose (FBG), fasting insulin (FINS), triglyceride (TG), total cholesterol (TCH), free fatty acid (FFA), glycosylated hemoglobin (GHb) and glycosylated serum proteins (GSP) were measured. The protein expression of peroxisome proliferator-activated receptor γ (PPARγ) in adipose tissues was detected by Western blotting. RESULTS: Compared with normal control group, the levels of FBG, GHb and blood lipids were increased in type 2 diabetic rats. The FINS, insulin sensitivity index, and the protein expression of PPARγ in adipose tissues were decreased. Compared with model group, the levels of FBG and GSP were decreased,and the FINS, insulin sensitivity index, and the protein expression of PPARγ in adipose tissues significantly increased in TTPGL treatment groups (with the doses of 120 and 240 mg/kg). The levels of serum TG,TCH and FFA were significantly lower in TTPGL treatment groups (P<0.01 or P<0.05) as compared with the model controls. CONCLUSION: TTPGL decreases the levels of blood glucose and lipids in diabetic rats. TTPGL also increases serum insulin level and improves insulin sensitivity. The action mechanism of TTPGL may be related to the increase in the protein expression of PPARγ.     

Effects of Aconiti tuber polysaccharides on hypercholesterolemia and hepatic cholesterol 7α-hydroxylase expression in rats

AIM: To investigate the effects of polysaccharides isolated from Aconiti tuber (Fuzi polysaccharides,FPS) on the prevention of hypercholesterolemia induced by high-cholesterol diet and the expression of hepatic cholesterol 7α-hydroxylase (cytochrome P450 7α-1, CYP7α-1) in rats.METHODS: Fifty male Wistar rats were randomly divided into 3 groups. The rats were fed with normal diet (control group), high-cholesterol diet (HC group) or high-cholesterol diet plus FPS (224, 448 or 896 mg·kg^-1·d^-1, FPS group) for 2 weeks. The serum lipid level, body weight, food-intake and fecal amount were measured at week 2. The pathological changes of the liver were observed with HE staining. The mRNA expression of hydroxy methylglutaryl coenzyme A (HMG-CoA) reductase and CYP7α-1, the protein level of CYP7α-1, and fecal bile acid were also detected at week 2.RESULTS: FPS significantly inhibited high-cholesterol diet-induced elevation of serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) (P<0.05). HE staining showed that FPS attenuated fatty degeneration in liver. Real-time PCR analysis showed that FPS significantly up-regulated the mRNA expression of CYP7α-1, but down-regulated the mRNA expression of HMG-CoA reductase (P<0.01). The protein level of CYP7α-1 was higher in FPS group than that in HC group (P<0.01). The level of fecal bile acid in HC-treated rats was higher than that in the control rats, and FPS stimulated the excretion of fecal bile acid (P<0.05).CONCLUSION: FPS significantly reduces serum cholesterol levels, which is associated with the up-regulation of hepatic CYP7α-1 expression and down-regulation of hepatic HMG-CoA reductase expression.     

Hypoxia-inducible factor-1α attenuates myocardial inflammatory injury induced by ischemia and reperfusion in rats

AIM:To investigate the role of hypoxia-inducible factor-1α (HIF-1α) stable expression in myocardial inflammatory injury induced by ischemia and reperfusion (I/R) in rats. METHODS:Male Wistar rats were randomly divided into 4 groups:sham operation (sham) group, I/R group, HIF-1α stabilizer dimethyloxalyl glycine (DMOG)+I/R group and HIF-1α inhibitor YC-1+I/R group. The protein expression of myocardial Toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB) was determined by Western blot. The mRNA levels of interleukin (IL)-1β, tumor necrosis factor-α (TNF-α), IL-6, TLR4 and NF-κB were detected by real-time PCR. The myeloperoxidase (MPO) activity in the myocardial tissues was measured. HE staining was used to observe the infiltration of inflammatory cells. RESULTS:HIF-1α decreased the infiltration of inflammatory cells, the MPO activity, and the mRNA levels of inflammatory factors IL-1β, IL-6 and TNF-α in the myocardial tissues. HIF-1α also reduced the expression of TLR4 and NF-κB at mRNA and protein levels (P<0.05). CONCLUSION:The stable expression of HIF-1α has an anti-inflammatory effect on the myocardial tissues after I/R injury in rats. The mechanism may be related to the inhibition of TLR4/NF-κB signaling pathway.     

Protective effects of sequoyitol on type 2 diabetic rats with liver inflammatory lesions

AIM：To investigate the possible protective effect of sequoyitol on type 2 diabetic rats with liver inflammatory lesions. METHODS：Type 2 diabetic rats were induced by feeding high-fat/high-sugar diet and injecting with a low dose of streptozotocin. Sequoyitol at doses of 12.5, 25 and 50 mg·kg-1·d-1 was orally administered in the model rats. At the end of the experiment, the rats were sacrificed. Serum levels of fasting blood glucose, alanine aminotransferase(ALT), aspartate aminotransferase(AST) and albumin(ALB) were determined. Liver wet was recorded and liver index was calculated. The levels of C-reactive protein(CRP),tumor necrosis factor α(TNF-α) and interleukin 6(IL-6) in the liver tissues were also measured. Real-time PCR was used to determine the mRNA expression of TNF-α. In addition, the pathological changes of the liver were observed with HE staining. RESULTS：Compared with the model rats, treatment with sequoyitol obviously decreased the levels of fasting blood glucose, ALT, AST, ALB, CRP, TNF-α and IL-6, reduced the liver index, down-regulated the mRNA expression of TNF-α in the liver, and ameliorated the pathologic changes of the liver. CONCLUSION：Sequoyitol attenuates liver lesions in type 2 diabetic rats through down-regulation of TNF-α and IL-6 expression.     

Effects of Youguiwan on microstructure and Hsp90 of chondrocytes in rats with knee osteoarthritis

AIM: To observe the effect of Youguiwan (YGW) on the expression of heat shock protein 90α (Hsp90α) in articular cartilage tissues of knee osteoarthritis (KOA) rats, and to further reveal its mechanism. METHODS: SD rats (n=60) were randomly divided into 6 groups:sham control (SC) group, model (M) group, glucosamine sulfate (GS) group, and high-, middle-and low-dose YGW (YGW-H, YGW-M and YGW-L) groups. The modified Hulth method was used to make KOA models for 6 weeks. The rats were gavaged with corresponding drugs for 8 weeks. HE staining was used and Makin score was evaluated. The expression of Hsp90α, fibronectin (Fn) and collagen type Ⅱ (COL-II) was determined by immunohistochemistry. The expression of interleukin-1β (IL-1β), matrix metalloproteinase (MMP)-3 and MMP-13 was analyzed by RT-qPCR. The protein expression of Hsp90α and COL-II was determined by Western blot. RESULTS: As compared with SC group, the Makin score was obviously raised in M group, the expression levels of Hsp90α, IL-1β, MMP-3 and MMP-13 were evidently increased, the expression levels of COL-II and Fn were evidently decreased (P < 0.01), articular cartilage was seriously damaged, and the chondrocytes were disarranged. As compared with M group, the Makin score and the expression of Hsp90α were obviously decreased in YGW-H group, the protein expression of Fn was evidently increased in YGW-H group, the protein expression of COL-II was evidently increased in YGW-H and YGW-M groups, the mRNA expressions of IL-1β, MMP-3 and MMP-13 were evidently decreased in YGW-H, YGW-M and YGW-L groups (P < 0.05 or P < 0.01), cartilage structure tended to be normal, the chondrocytes distribution was uneven, and articular cartilage surface was not smooth. CONCLUSION: Youguiwan is effective for treatment of KOA. Youguiwan protects against articular cartilage degeneration by down-regulating the expression of Hsp90α and up-regulating the expression of Fn, and reducing the secretion of inflammatory factors and the degradation of extracellular matrix.     

Effect of gingko biloba extract on liver from experimental type 2 diabetic rats

AIM:To study the protective effect of the ginkgo biloba (EGB) extract on liver from experimental type 2 diabetic rats and to explore its possible mechanism. METHODS:Thirty-nine male Sprague-Dawley rats were divided randomly into four groups: normal control group, high-fat group, diabetic group and EGB-treated group. After fed with high-fat diet for 4 weeks, the later two groups were injected with streptozotocin intraperitoneally to induce type 2 diabetes mellitus. EGB-treated group was injected intraperitoneally with EGB at a dose of 8 mg·kg^-1·d^-1, and the other three groups were treated with normal saline of the same volume. After 8 weeks, the morphologic change of hepatic tissue was observed under transmission electron microscope (TEM) and light microscope (LM), respectively. In addition, the activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX), total nitric oxide synthase (TNOS), inducable nitric oxide synthase (iNOS) and the content of malondialdehyde (MDA), nitric oxide (NO) in liver homogenate were detected biochemically. RESULTS:Obvious liver fatty degeneration, apparent decrease of glycogen granules in cytoplasm of hepatocytes under light microscope and hepatocytes pyknosis, lots of lipid deposits in cytoplasm of hepatocytes, proliferation of hepatic stellate cells and collagen under TEM were observed in diabetic group. The activity of SOD, CAT, GSH-PX decreased but the activity of tNOS, iNOS and the content of MDA, NO^-₂/NO^-₃ increased in diabetic group compared with normal control group. The pathological change was relieved in EGB-treated group. The activity of SOD, CAT, GSH-PX increased, the activity of tNOS, iNOS and the content of MDA, NO^-₂/NO^-₃ decreased in the liver of rats in EGB-treated group compared with diabetic group. CONCLUSION:EGB exerts a beneficial effect on liver in experimental type 2 diabetic rats. Anti-lipid peroxidation and suppression of NO production may be involved in this process.     

Gene expression of 5α-reductase (type 2) in reproductive gland of pubertal diabetic rats

AIM: To study the molecular mechanism of reproduction dysfunction in pubertal diabetic rat, the level of 5α-reductase (type 2) mRNA in testis, epididymis and prostate in diabetic rat was detected. METHODS: The gene expression of 5α-reductase (type 2) was detected by Northern blot. RESULTS: In the caput of the epididymis, the expression of 5α-reductase (type 2) mRNA of D and ID groups was less than that of C group. CONCLUSION: The decreased expression of 5α-reductase (type 2) results in the decreased production of dihydrotestosterone, which influences the development and function of reproduction system in pubertal rats.     

Expression of perilipin and ADRP in rat liver tissues with abnormal glucose metabolism

AIM: To observe the changes of perilipin and adipose differentiation-related protein (ADRP) du-ring the development of diabetes mellitus and to explore the effect of perilipin and ADRP on abnormal glucose metabolism with non-alcoholic fatty liver disease (NAFLD). METHODS: The rat model of impaired glucose tolerance (IGT) was induced by feeding high-fat diet, and the type 2 diabetes mellitus (T2DM) model was induced by feeding high-fat diet for 4 weeks and intraperitoneally injecting streptozotocin. The morphological change of the liver tissue was observed under optical microscope. The serum contents of perilipin and ADRP were measured by ELISA. The mRNA expression of perilipin and ADRP in the liver tissues was detected by real-time PCR. The protein expression of ADRP in the liver tissues was determined by Western blotting. RESULTS: HE staining showed steatosis in the liver of the rats in IGT group was more serious than that in T2DM group. The biochemical and the pathological processes of rat models were consistent with the clinical feature of related diseases. The serum content of perilipin had no difference among various groups. The mRNA expression of perilipin in IGT group and T2DM group was significantly higher than that in control group. Compared with IGT group, the mRNA expression of perilipin in T2DM group was significantly increased. The serum content of ADRP in T2DM group was significantly lower than that in control group. The mRNA and protein expression of ADRP in model groups was significantly lower than that in control group. Compared with IGT group, the mRNA expression of ADRP in T2DM group was significantly reduced. CONCLUSION: The serum content of ADRP plays a role in the development and progression of T2DM. It is negatively correlated with HOMA-IR. NAFLD occurs during progression of abnormal glucose metabolism induced by feeding high-fat diet. The development of abnormal glucose metabolism with NAFLD is probably related to the increased expression of perilipin and the reduced expression of ADRP.     

Protective effect of curcumin analogue L6H4 on diaphragm of type 2 diabetic rats

AIM: To investigate the protective effect of curcumin analogue L6H4 on diaphragm of type 2 diabetic rats.METHODS: SPF male Sprague-Dawley rats (n=40) were randomly divided into 5 groups: normal control (NC) group, high fat (HF) group, high fat+L6H4 treatment (FT) group, diabetes mellitus (DM) group and DM+L6H4 treatment (DT) group. The rats in the later 4 groups were fed with high-fat diet. After 4 weeks of high-fat diet fee-ding, the rats in DM and DT groups were intraperitoneally injected with streptozotocin to induce type 2 diabetes melliutus. The rats in FT and DT groups were given L6H4 by gavage for 8 weeks. Blood glucose and blood lipid levels were detected biochemically. Fasting serum insulin (FINS) level was measured by radioimmunoassay and insulin resistance index (HOMA-IR) was calculated. Serum adiponectin (APN) level was measured by ELISA. The morphological changes of the diaphragm were observed under light and transmission electron microscopes. Lipid deposition and the activity of succinate dehydrogenase (SDH) and NADH-tetrazolium reductase (NADH-TR) were observed by enzyme histochemical staining. The content of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) in the diaphragm were measured by thiobarbituric acid method and hydroxylamine method, respectively. The protein expression of adiponectin receptor 1 (AdipoR1) in the diaphragm was determined by immunohistochemistry and Western blot. RESULTS: The levels of blood lipids, blood glucose, FINS and HOMA-IR in HF and DM groups were higher than those in NC group, but decreased after L6H4 treatment. The serum APN level in HF and DM groups was lower than that in NC group, but increased after treatment with L6H4. The muscle fibers of the diaphragm were shrunk, fat particles accumulated in the muscle fibers, and the mitochondria were slightly swollen in HF and DM groups. The diaphragmatic fibrosis was obvious in DM group. These lesions were relieved after L6H4 treatment. Compared with NC group, the level of MDA and the activity of SDH and NADH-TR in the diaphragm were increased in HF and DM groups, but decreased after treatment with L6H4. The activity of SOD and the expression of AdipoR1 in the diaphragm were lower than those in NC group, but increased after L6H4 treatment.CONCLUSION: The curcumin analogue L6H4 exerts a protective effect on diaphragm in type 2 diabetic rats. The strengthened protein expression of AdipoR1, the increased serum level of APN, and anti-lipid peroxidation may be involved in the process.