Influence of chronic stress on vasoactive substances and inflammatory factor in rat model with acute myocardial infarction by factorial analysis

AIM: To investigate the effect of chronic unpredictable mild stress(CUMS) on plasma endothelin, nitric oxide and interleukin-6, high-sensitivity C-reactive protein(hs-CRP) in rats after acute myocardial infarction(AMI).METHODS: After the rats of myocardial infarction(MI) were established, the animals were treated under the condition of CUMS for 4 weeks, then the contents of plasma(or serum) endothelin, nitric oxide, interleukin-6 and hs-CRP were measured and data were analyzed by two factor factorial analysis. RESULTS: The results of factorial analysis showed: MI alone had no significantly effect on the level of nitric oxide(P>0.05), but CUMS had significantly effect on increasing the level of nitric oxide(P<0.01). The CUMS had significantly interaction with MI on increasing the level of nitric oxide(P<0.01). Both MI and CUMS increased the level of hs-CRP(all P<0.01). However, no interaction was discovered between MI and CUMS(P>0.05). Both MI and CUMS had no effect on the level of ET-1 and IL-6(P>0.05).CONCLUSION: CUMS increases nitric oxide content and has cooperative effect with MI on increasing NO, both MI and CUMS significantly increase the level of CRP, but have no effect on the level of ET-1 or IL-6, suggesting that the abnormal increase in nitric oxide and hs-CRP contents may be the important pathophysiological changes of post-MI depression.     

Effect of salvianolic acid B on vasodilatory function,NF-κB activation and inflammatory cytokine expression in diabetic rats

AIM: To investigate the ameliorative effect of salvianolic acid B on vasodilatory function in diabetic rats and the possible mechanisms. METHODS: SD rats (n=40) were fed on high-sugar and high-fat diet for 4 weeks, followed by a single intraperitoneal injection of streptozotocin (40 mg/kg). The rats with random blood glucose level over 16.7 mmol/L were considered diabetic and randomly allocated to 3 groups, namely model group, low dose (80 mg·kg^-1·d^-1) of salvianolic acid B group and high dose (160 mg·kg^-1·d^-1) of salvianolic acid B group. The rats in salvianolic acid B groups were intragastrically administered with corresponding doses of salvianolic acid B for 6 weeks. Vasodilatory function was measured as endothelium-dependent and-independent vasodilation of the aortic rings. The primary histopathological changes of aorta were observed by HE staining. Serum levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and C-reactive protein (CRP) were measured by ELISA. The levels of total antioxidant capacity, malondialdehyde (MDA) and nitric oxide (NO) in aortic tissues were evaluated by colorimetric assays. The protein levels of intercellular adhesion molecule-1 (ICAM-1) and monocyte chemotactic protein-1 (MCP-1), and the activation of nuclear factor-κB (NF-κB) were determined by Western blot. RESULTS: Treatment with salvianolic acid B evidently ameliorated endothelium-dependent diastolic function and pathological changes of aorta in diabetic rats (P<0.05 or P<0.01). Supplementation with salvianolic acid B resulted in significant increases in NO content and total antioxidant capacity in aortic tissues, accompanied by marked decreases in the level of MDA in aorta tissues and the serum levels of IL-6, TNF-α and CRP (P<0.05 or P<0.01). Salvianolic acid B markedly down-regulated NF-κB p65 nuclear translocation and protein expression of ICAM-1 and MCP-1 in aorta tissues (P<0.05 or P<0.01). CONCLUSION: Salvianolic acid B effectively ameliorates endothelium-dependent diastolic function of aorta in diabetic rats, which might be attributed to suppression of NF-κB activation and subsequent expression of inflammatory cytokines. The beneficial effect of salvianolic acid B on vascular endothelium might be derived from its antioxidant capacity.     

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.     

Qishen-Yiqi dripping pills attenuate atherosclerosis by regulating Ca2+ homeostasis via TRPC1/STIM1 pathway

AIM:To explore the therapeutic effect of Qishen-Yiqi dripping pills (QS) on atherosclerosis (AS) and the mechanism. METHODS:AS rat model was established by high-fat diet, and SD rats were randomly divided into normal control group, AS model group, low-dose, middle-dose and high-dose QS groups, and positive group (n=6 each). After administration for 12 weeks, serum samples were collected to detect the serum lipid and Ca²⁺ levels. HE staining was used evaluated the histopathological changes of arterial tissue. The serum levels of interleukin-1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α) were measured by ELISA. The nitric oxide (NO) level was detected by nitrate reductase method. The protein levels of transient receptor potential channel protein 1 (TRPC1), stromal interaction molecule 1 (STIM1) and endothelial NO synthase (eNOS) were determined by Western blot. RESULTS:QS significantly reduced the arterial damage via inhibiting the formation of atherosclerotic plaque and attenuated intimal thickening and vascular stenosis. Compared with AS group, the serum levels of total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) were decreased significantly and the levels of high-density lipoprotein cholesterol (HDL-C) were increased significantly in high-dose QS group (P<0.05). The serum levels of IL-1β, IL-6 and TNF-α in high-dose QS group were lower than those in AS group (P<0.05). Compared with AS group, the serum Ca²⁺ level was lowered and the arterial tissue NO level was elevated in QS groups (P<0.05). Compared with AS rats, the protein levels of TRPC1 and STIM1 were decreased significantly and the protein level of eNOS was increased significantly in the rats treated with QS (P<0.05). CONCLUSION:QS regulate calcium homeostasis via TRPC1/STIM1 pathway, increase the production of NO and inhibit the inflammatory responses, thus exerting anti-AS effect.     

Protective effect of DIZE on heart function of rats with diabetic cardiomyopathy

AIM: To observed the protective effect of diminazene aceturate (DIZE), an angiotensin-converting enzyme 2 (ACE2) activator, on rats with diabetic cardiomyopathy (DCM). METHODS: Male Wistar rats (n=30) were randomly divided into normal control group, DCM group and DIZE treatment group (DIZE group). The rats in DCM group and DIZE group were intraperitoneally injected with streptozotocin (65 mg/kg) to establish diabetic model. After 12 weeks, the diabetic rats were infused with DIZE at 15 mg·kg^-1·d^-1 or the same volume of saline for 4 weeks using osmotic minipump. The cardiac function was measured at the end of the 16th week. The methods of Mason staining and HE staining were used to observe the morphological changes of the myocardial tissue. Western blot, ELISA and immunohistochemistry were used to observe the changes of ACE2, angiotensin (Ang)Ⅱ, Ang-(1-7), interleukin (IL)-1, IL-6 and connective tissue growth factor (CTGF). RESULTS: DIZE significantly improved the expression of ACE2 in diabetic rats (P<0.05). Compared with DCM group, the levels of IL-1 and IL-6 in DIZE group were significantly decreased, and the cardiac function in DIZE group was significantly improved (P<0.05). CONCLUSION: ACE2 endogenous agonist DIZE significantly increases the ACE2 level and reduces the level of inflammation, thus protecting the heart function of DCM rats.     

Role of endogenous nitric oxide synthase inhibitor in erectile dysfunction of diabetic rats

AIM: To investigate the role of nitric oxide synthase (NOS) inhibitor asymmetric dimethylarginine (ADMA) in erectile dysfunction of diabetic rats.METHODS: Type 2 diabetic rat model was established by 4 weeks of high-fat diet plus a single intraperitoneal injection of streptozotocin and continued high-fat diet feeding for 8 weeks. Corpus cavernosum was isolated from the rats under anesthetization, and the endothelium-dependent relaxation response to acetylcholine (ACh) was tested in an organ chamber to reflect erectile function. The level of ADMA in serum was detected. The NOS activity, nitric oxide (NO) content and cyclic guanosine monophosphate (cGMP) content in corpus cavernosum were measured. The protein expression of ADMA-NOS-NO pathway-related molecules and phosphodiesteras 5 (PDE5) in the corpus cavernosum was detected by Western blot. Superoxide dismutase activity and malondialdehyde content were analyzed to evaluate oxidative stress.RESULTS: Elevated blood glucose and lowered insulin sensitivity were observed in the diabe-tic rats, indicating that type 2 diabetic rat model was successfully established. Compared with control group, the relaxation response to ACh of corpus cavernosum from diabetic rats was significantly decreased, which was accompanied with the elevation of serum ADMA level and reduction of NOS activity, NO content and cGMP content in the corpus cavernosum. The protein expression of ADMA-generating enzyme protein arginine methyltransferase 1 was up-regulated, while ADMA-metabolic enzymes dimethylarginine dimethylaminohydrolases 1 and 2, and ADMA-targeting enzymes endothelial NOS and neuronal NOS were down-regulated. The protein expression of PDE5 was up-regulated, accompanied with an increase in oxidative stress in the corpus cavernosum of diabetic rats. Incubation of isolated corpus cavernosum from normal rats with NOS inhibitor ADMA induced the similar relaxation dysfunction of corpus cavernosum response to ACh and decreased NO and cGMP contents in diabetic rats.CONCLUSION: Elevated endogenous NOS inhibitor ADMA plays an important role in erectile dysfunction of diabetic rats. The underlying mechanism may be related to the reduction of NO production and the increase in oxidative stress.     

Effect of rosiglitazone on serum resistin and glomerular sclerosis in type 2 diabetic rats

AIM: To observe the effect of rosiglitazone on serum resistin level and to investigate the possible mechanism of glomerular sclerosis in type 2 diabetic rats. METHODS: Ten-week-old Wistar rats were divided into diabetic nephropathy (DN) group (10 cases) and DN+rosiglitazone group (10 cases). The other 10 Wistar rats were used as normal control group. Type 2 diabetic rats were induced by cutting the right kidney and injecting small dose (35 mg/kg) of streptozocin (STZ). Rosiglitazone group received rosiglitazone 10 mg·kg-1·d-1 while normal control group and DN group were fed with normal chow diet. After 20 weeks, vessel blood was collected for plasma IL-1, TNF-α and resistin assayed by ELISA. The serum levels of glucose, creatinine, urea nitrogen and microalbum of 24 h urine were also detected. The expression of TGF-β1 in glomerulus was examined by immunohistochemistry. Smad2 phosphatase activity was detected by Western blotting. RESULTS: The plasma IL-1, TNF-α, hs-CRP and resistin, and microalbum of 24 h urine in rosiglitazone group, were significantly lower than those in DN group while the serum level of glucose was not different from that in DN group. The expression of TGF-β1 and phosphorylated level of Smad2 were lower in rosiglitazone group than those in DN group. The degree of glomerular sclerosis in rosiglitazone group was obviously lighter than that in DN group. CONCLUSION: Rosiglitazone delays and ameliorates the development of diabetic glomerular sclerosis. The mechanism is possibly related to the modulation of resistin and other inflammatory factors. Anti-inflammation is a potential way for controlling diabetic nephropathy.     

Bacterial cell wall components of Staphylococcus aureus induce endophthalmitis

AIM: To compare the responses of intraocular inflammation induced by heat-inactivated Staphylococcus aureus or its bacterial cell wall components in SD rats. METHODS: The rats were randomly divided into heat-inactivated bacteria (HIB) group (96 rats were injected with 10 μg of HIB), heat-inactivated bacteria fragments (HIBF) group (96 rats were injected with 10 μg of HIBF), peptidoglycan (PGN) group (96 rats were injected with 10 μg of PGN) and control group (96 rats were injected with sterile saline equivalent). At time points of 6 h, 12 h, 24 h, 48 h, 72 h and 5 d after vitreous injection of the pathogens, the ocular inflammation scores were determined under slit lamp microscope. The infiltration of white blood cells were counted in histological sections. The levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and cytokine induced neutrophil chemoattractant-1 (CINC-1) in serum and vitreous body were detected by ELISA, and protein concentration in aqueous humor were also measured. RESULTS: Severe ocular inflammation was observed in the animals of HIB, HIBF and PGN groups 6-72 h after injection. Five days after injection, the endophthalmitis subsided. The peak of intraocular white blood cell infiltration was observed 24 h after exposure to the bacteria and the components in each group and the cell infiltration rapidly declined after 3 days. The concentrations of TNF-α and IL-1β peaked at 24 h in each group, maintained to 48 h, then decreased rapidly, and returned to baseline level after 5 days. The concentration of CINC-1 peaked at 12 h in each group, and maintained to 24 h, then decreased rapidly, and returned to the normal level after 3 days. Significantly higher protein levels in aqueous humor were detected in the experimental groups at all time points as compared to that in control group (P<0.01). CONCLUSION: Staphylococcus aureus cells and its components induce typical experimental endophthalmitis in SD rats. Massive leukocyte infiltration and high levels of TNF-α, IL-1β and CINC-1 are the main pathological features in the experimental model. PGN and the bacterial cell wall fragments induce stronger intraocular inflammations than the whole heat-inactivated S. aureus.     

Sphingosine-1-phosphate receptor-2 attenuates lipopolysaccharide-induced acute lung injury

AIM: To investigate the effects and mechanisms of sphingosine-1-phosphate receptor-2 (S1P2R)on lipopolysaccharide (LPS)-induced acute lung injury (ALI). METHODS: ALI model was induced by intratracheal administration of LPS in both wild-type mice and S1P2R -deficient mice. The pathological changes in the lung tissues were observed, and the protein concentration, total cell number, neutrophil ratio, TNF-α level and IL-6 level were determined in the bronchoalveolar lavage fluid (BALF) 24 h after LPS injection. In order to investigate the mechanisms of S1P2R in LPS-induced ALI, 10 min before LPS injection, both wild-type mice and S1P2R -deficient mice were injected with nitric oxide synthase inhibitor by tail vein injection, the pathological changes of the lung tissues were observed, and the protein concentration and total cell number in BALF were determined 12 h after LPS injection. RESULTS: Compared with wild-type mice, S1P2R -deficient mice showed more severe LPS-induced ALI, and the protein concentration, neutrophils and inflammatory cytokines in BALF were significantly increased in S1P2R -deficient mice. Administration of nitric oxide synthase inhibitor N^ω-L-nitro-arginine methyl ester protected S1P2R -deficient mice from aggravation of ALI. CONCLUSION: S1P2R mediates the protection from LPS-induced ALI possibly through inhibiting nitric oxide synthase.     

Effects of baicalin on serum levels of IL-6 and IL-4 in mouse periodontitis

AIM: To investigate the effect of baicalin on experimental periodontitis in mouse model by comparing the histological changes in periodontal tissues and serum levels of inter leukin(IL)-6/IL-4 in mice, and to analyze the role of baicalin in immune regulation and anti-inflammatory mechanisms. METHODS: Twenty-seven male Kunming mice (SPF grade, 12-week-old) were randomly divided into 3 groups. The naive mice were used in normal control group. In experimental periodontitis group, the periodontitis model was produced by ligature of braided silk around the first maxillary molar and inoculation with putative periodontopathic bacteria. Five weeks after the ligature, the mice were fed with 10% glucose, and gavaged with distilled water. In baicalin treatment+periodontitis group, the periodontitis model was induced as above, then gavaged with baicalin at the beginning of the fifth week after the ligature. The mice were sacrificed at week 4, 6 and 8. The histological changes of the periodontal tissues were observed under microscope with hematoxylin and eosin (HE) staining. The serum level of IL-6 and IL-4 in the mice were determined by ELISA. RESULTS: The periodontal tissues showed moderate inflammatory damages in experimental periodontitis group. The periodontal destruction was significantly reduced in baicalin treatment+periodontitis group. The serum level of IL-6 in experimental periodontitis group was significantly higher than that in control group and baicalin treatment+periodontitis group (P<0.01), and the serum level of IL-6 in baicalin treatment+periodontitis group was significantly lower than that in periodontitis group at week 6 and 8 (P<0.01). The serum level of IL-4 in periodontitis group was significantly lower than that in control and baicalin treatment+periodontitis group (P<0.01). The serum level of IL-4 in baicalin treatment+periodontitis group was significantly higher than that in periodontitis group at weeks 6 and 8 (P<0.01).CONCLUSION: The pathogenesis of periodontitis is closely related to the imbalance of Th1/Th2 cytokines, characterized by increased serum level of IL-6 and the decreased serum level of IL-4. Baicalin plays a significant role in treating mouse periodontitis by decreasing the serum level of IL-6 and increasing the serum level of IL-4.     

Expression and probable role of extracellular signal-regulated protein kinases in renal fibrosis associated with diabetic in mice

AIM: To investigate the expression and probable role of extracellular signal-regulated protein kinase (ERK1/2) in renal fibrosis associated with diabetic in mice.METHODS: Male homozygous C57BL/6 mice were divided at random into control group (intraperitoneally injected with citrate buffer) and diabetes group (received 5 consecutive daily intraperitoneal injections of streptozotocin at dose of 50 mg·kg^-1·d^-1).All mice were followed up for 16 weeks.Diabetes was confirmed by serum glucose levels exceeding 16.7 mmol/L.Mice were killed at 0,4,8,12 and 16 weeks respectively after streptozotocin injection.The kidney tissues were obtained from diabetic and control mice.Serum glucose,kidney weight/body weight (KW/BW),24 h albumin excretion rate (UAE) and the serum creatinine (Scr) were measured.The kidney tissue was used for histological and morphometric studies of glomerular size,glomerular matrix expansion (PAS),and the expression of TGF-β₁,phosphorylated ERK1/2 and collagen Ⅲ by immunohistochemical staining.RESULTS: The serum level of glucose in streptozotocin -induced diabetic mice increased significantly.The kidney weight/body weight ratio,glomerular volume and glomerular matrix expansion in diabetic mice were obviously higher than those in control mice.Serum creatinine and 24 h albumin excretion rate in diabetic mice increased significantly compared with control mice.TGF-β₁,phosphorylated ERK1/2 and collagen Ⅲ levels were obviously increased in the kidney of diabetic mice compared with those in control mice (P<0.01).TGF-β₁ expression was positively related to the expression of phosphorylated ERK1/2.CONCLUSION: The overexpression of phosphorylated ERK1/2 in diabetic kidney may play an important role in the development of renal fibrosis associated with diabetic nephropathy in mice.     

Protective effect of C1q/tumor necrosis factor-related protein 3 on vascular endothelium in rats with hyperuricemia

AIM To study whether C1q/tumor necrosis factor （TNF）-related protein 3 （CTRP3）protect vascular endothelium in rats with hyperuricemia and its potential mechanisms. METHODS An animal model of hyperuricemia was established by using male SD rats drinking 10% fructose water （n=10）. The rats drinking normal water served as normal controls （n=10）. After 12 weeks, the rats were given a single injection with Ad-CTRP3 or Ad-GFP. The experiment was ended at 14th day after transfection.The serum levels of uric acid and nitric oxide （NO） were evaluated. The serum contents of TNF-α and interleukin-6 （IL-6） were measured by ELISA. HE staining and TUNEL assay were used to assess the morphological changes of intima and apoptosis of endothelial cells in thoracic aorta, respectively. The mRNA levels of endothelial nitric oxide synthase （eNOS）, TNF-α and IL-6 were detected by RT-qPCR. The protein levels of CTRP3 and Toll-like receptor 4 （TLR4） were determined by Western blot. RESULTS Compared with normal control group, the rats with hyperuricemia showed lower CTRP3 and higher TLR4 protein levels in the thoracic aorta （P<0.05）. Hyperuricemic rats had higher serum contents of uric acid, TNF-α and IL-6 （P<0.05）. Also, the intima structure disturbance of thoracic aorta, increased apoptotic rate, higher mRNA levels of TNF-α and IL-6 as well as lower mRNA levels of eNOS were observed （P<0.05）. By contrast, CTRP3 over-expression decreased TLR4 protein levels, reduced inflammatory cytokines, and obviously improved the morphology and function of thoracic aorta in the rats with hyperuricemia. CONCLUSION CTRP3 protect vascular endothelium in rats with hyperuricemia maybe via down-regulation of TLR4- mediated inflammatory signaling pathway.     

PPARs signaling pathway is involved in diabetic hepatopathy in mice

AIM: To investigate the role of peroxisome proliferator-activated receptors (PPARs)-inflammation signaling pathways in diabetic hepatopathy. METHODS: Diabetic mouse model was established by feeding the mice with a high-energy diet for 4 weeks combined with intraperitoneal injection of streptozotocin (STZ; 40 mg·kg^-1·d^-1 for 5 d). The hepatopathy model was confirmed by histopathological observation and the indexes of liver function, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP), after another 4 weeks. Moreover, fasting blood glucose (FBG), and serum levels of total cholesterol (TC), triglyceride (TG) and insulin were measured, and the HOMA insulin resistance index (HOMA-IR) was calculated. The mRNA and protein expression levels of PPARs and inflammation-related factors were measured by qPCR and Western blot, respectively. RESULTS: After treatment with STZ for 7 d, the FBG of mice exceeded 11.1 mmol/L, suggesting that the diabetic model was established. After 4 weeks, the structural deformation of the hepatocytes (including hepatocytes containing abundant fat vacuoles, and inflammatory cell infiltration), and the increases in the serum levels of insulin, HOMA-IR, TC, TG, ALT, AST and ALP were observed (P<0.01), indicating the occurrence and progression of hepatopathy in diabetic mice. Meanwhile, compared with the control group, the mRNA and protein expression of PPARα, PPARβ and PPARγ decreased, but the expression of nuclear factor-κB (NF-κB), cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS) significantly increased in the diabetic hepatopathy mice (P<0.01). CONCLUSION: Down-regulation of PPARα, PPARβ and PPARγ and activation of NF-κB-COX-2/iNOS signaling pathways may be involved in the diabetic hepatopathy in mice induced by long-term high-energy diet feeding combined with intraperitoneal injection of STZ.     

Influence of losartan potassium on renal expression of TGF-β1, CD68 and MCP-1 in type 2 diabetic nephropathy rats

AIM: To observe the effects of losartan potassium on renal expression of transforming growth factor beta 1(TGF-β₁), CD68 and monocyte chemoattractant protein-1 (MCP-1) in type 2 diabetic nephropathy rats for exploring the protective mechanism of losartan potassium on type 2 diabetic rat kidney. METHODS: Thirty Sprague-Dawley rats were randomized into 3 groups: normal control group, model group and treatment group. The morphology of kidney tissues, the renal function, and the change of 24 h urinary protein quantitative index were measured after 15 weeks of treatment, while TGF-β₁, CD68 and MCP-1 expression in kidney cortex was observed by immunohistochemistry. RESULTS: Compared with the normal control rats, the body weight of the rats was lower in other groups, but the levels of blood glucose, triglyceride and cholesterol were higher.The expression of CD68, MCP-1 and TGF-β₁, 24 h urinary protein quantitative index and serum creatinine were higher in model group than those in normal control rats. However, compared with model group, serum creatinine, 24 h urinary protein quantitative index and the expression of CD68, MCP-1 and TGF-β₁ were decreased in treatment group. CONCLUSION: Losartan potassium protects the kidney of diabetic nephropathy rats through inhibiting the expression of TGF-β₁ and MCP-1 in the kidney and restraining macrophage infiltration.     

Protective effects of extract of Ginkgo biloba on diaphragm of diabetic rats

AIM: To investigate the effects of extract of Ginkgo biloba (EGb) on diaphragm from diabetic rats. METHODS: Sprague-Dauley rats were divided into three groups: normal control, diabetic group and EGb treatment group. The morphologic changes of diaphragm tissues were studied by light and electron microscopy, the activities of succinate dehydrogenase (SDH), superoxide dismutase (SOD), nitric oxide synthase (NOS) and contents of malondialdehyde (MDA), nitric oxide (NO₂^-/NO₃-) in the diaphragm mitochondria were assayed by spectophotometer, respectively. RESULTS: The activities of SOD, SDH decreased in diabetic diaphragm mitochondria, but the activitiy of NOS, the contents of NO₂^-/NO₃^-, MDA increased compared with control group. The activities of SOD, SDH were increased as well as NOS were decreased and the contents of NO₂^-/NO₃^-, MDA decreased in EGb treatment group compared with the diabetic group. CONCLUSION: EGb may protects the diaphragm mitochondria of diabetic rats by enhancing the function of respiratory chain, anti-oxidation and decreasing NO level.     

Trichinella spiralis infection alters mouse colonic epithelial permeability

AIM: To study the effect of Trichinella spiralis ( T. spiralis ) infection on colonic epithelial permeability in mice.METHODS: T. spiralis was applied to infect BALB/c mice. Seven days after infection, horseradish peroxidase (HRP) was infused into the rectum of the mice infected with T. spiralis . Serum HRP was detected in the subsequent 0 min, 60 min and 120 min. The expression of interleukin-4 (IL-4) in mesenteric lymph nodes was detected by ELISA. Additionally, T. spiralis was also applied to infect STAT6 knockout mice, and the above indexes were also determined. RESULTS: In BALB/c mice, T. spiralis infection significantly increased colonic permeability. IL-4 and IgG₁ was significantly higher, IgG_2a was significantly lower (all P<0.05) after infection. However, in STAT6 knockout mice, T. spiralis infection did not change colonic permeability (P>0.05). Compared with BALB/c infection group, IL-4 level in STAT6 knockout infection group was significantly lower (P<0.05). CONCLUSION: T. spiralis infection induces an increase in mouse colonic epithelial permeability by promoting the secretion of IL-4.     

Interleukin-1β inhibits AKT to down-regulate eNOS Ser1177 phosphorylation in human umbilical vein endothelial cells

AIM To investigate whether interleukin-1β （IL-1β） regulates endothelial nitric oxide synthase （eNOS） phosphorylation at Ser1177 site in human umbilical vein endothelial cells （HUVECs）, and to explore its possible mechanism. METHODS The HUVECs were randomly divided into normal control group, tumor necrosis factor-α （TNF-α） group, IL-1β group, IL-6 group, SC79 ［protein kinase B （PKB/AKT） specific agonist］ group and SC79+IL-1β group. Western blot was used to determine the protein levels of eNOS, p-eNOS-Ser1177, AKT and p-AKT-Ser473 in the HUVECs. Chemical colorimetry was used to detect the nitric oxide （NO） content in the culture medium of HUVECs. RESULTS No statistically significant difference of p-eNOS-Ser1177 level in HUVECs treated with TNF-α and IL-6 was observed as compared with normal control group （P>0.05）, while the protein level of p-eNOS-Ser1177 in the HUVECs and the content of NO in the culture medium of HUVECs decreased significantly in IL-1β group （P<0.05）, and the protein level of p-AKT-Ser473 in the HUVECs was decreased as compared with normal control group （P<0.05）. The AKT agonist SC79 blocked the down-regulation effect of IL-1β on p-eNOS-Ser1177 level in the HUVECs and NO content in the culture medium of HUVECs （P<0.05）. CONCLUSION IL-1β down-regulates the protein level of p-eNOS-Ser1177 in HUVECs and affects the activity of eNOS, which may be involved in AKT/eNOS signaling pathway.     

Expression and role of SnoN in kidney tissue of diabetic rats

AIM: To observe the changes of SnoN expression in renal tissues of diabetic rats, and to elucidate the role of co-repressor SnoN protein in the diabetic nephropathy. METHODS: Diabetic nephropathy was induced by intravenous injection of streptozotocin in male Sprague-Dawley rats. The model animals were divided into 2 weeks, 4 weeks and 8 weeks groups randomly. Meanwhile other 3 age-matched normal control groups were set up. The expressions of SnoN, TGF-β₁, Smad2/3, APC were detected by immunohistochemistry staining. The SnoN proteins in renal cortex were detected by Western blotting. Blood glucose, serum creatinine and 24 h urine protein were examined by biochemistry methods. The renal morphology was checked on PAS staining sections under light microscopy. RESULTS: The results of immunohistochemistry and Western blotting showed that the expression of SnoN in diabetic renal tissues at 2 weeks was the same as the normal kidney. There was a significant decrease in DM 4 weeks (P<0.01). A time dependent increases in TGF-β₁, Smad2/3 and APC were detected in the kidney of diabetic mellitus rats. The degree of SnoN down-regulation had close relation with the increases in TGF-β₁, Smad2/3 and APC. CONCLUSION: These results suggest that in the DM, renal increase in TGF-β₁ expression may down-regulate the SnoN expression through APC dependent degradation, indicating a key role in the mechanism of diabetic nephropathy.