Folic acid reduces monocyte chemoattractant protein-1 expession in aorta of rats with hyperhomocysteinemia

AIM: To investigate the effects of folic acid on the expression of monocyte chemoattractant protein-1 (MCP-1) in aorta of rats with hyperhomocysteinemia induced by ingestion of execess methionine (Met). METHODS: Thirty male SD rats ［(200±20） g］ were divided into 3 groups (n=10 for each group): control group (fed with normal diet), high Met group (fed with normal diet enriched by 1.7% Met) and Met plus folate group (fed with normal diet plus 1.7% Met and 0.006% folate). The animals were fed with different regiments for 45 days. Levels of total plasma homocysteine (Hcy) were detected. The expression of MCP-1 protein in aorta was detected by immunohistochemistry and Western blotting. RESULTS: The high-methionine diet resulted in a significant increase in plasma Hcy levels (P<0.01). Serum Hcy levels were significantly lower in rats fed with high-methionine plus folate-rich diet than that in rats fed with high-methionine diet (P<0.01). The expression of MCP-1 were higher in aorta of rats fed with high-methionine diet than those in control rats (46.41±4.23 vs 15.73±2.74, P<0.05). The expression of MCP-1 was significantly reduced in aorta of rats fed with high-methionine plus folate-rich diet compared with rats fed with high-methionine diet (23.12±4.40 vs 46.41±4.23, P<0.05). CONCLUSION: High methionine diet for 45 days is sufficient to induce hyperhomocysteinemia. Folate supplementation to the rats fed with the high-methenine diet prevents elevation of Hcy levels in blood, and reduces the expression of MCP-1 in aorta of rats with hyperhomocysteinemia.     

Correlation between intracellular magnesium and expression of beta 2-adrenergic receptor mRNA in the lung of C57BL/6 asthmatic mice

AIM: To explore the effect of intracellular magnesium on expression of beta 2-adrenergic receptor mRNA in the lung of C57BL/6 asthmatic mice. METHODS: Ninety-six healthy, 4-6 weeks old and female C57BL/6 mice, weighting (12±2) g, were randomly divided into the following A, B, C, D groups with 24 mice in each group. The mice were sensitized and challenged by ovalbumin to establish the asthmatic model. A and B groups were fed with magnesium deficient diet. C and D groups were fed with normal magnesium level diet. B and D groups were injected intraperitoneally with 0.2 mL sulphate salbutamol solution after OVA provocation. A and C groups were injected intraperitoneally with 0.2 mL saline as control. Eight mice in each group were randomly taken out at 1 d, 21 d, 34 d to detect plasma Mg2+, intracellular Mg2+, the beta 2-AR mRNA and protein in lung tissue. RESULTS: No significant difference in plasma Mg2+, intracellular Mg2+, the beta 2-AR mRNA and protein in lung tissue among all groups at 1st d was observed (P>0.05, respectively). Plasma Mg2+, intracellular Mg2+, the beta 2-AR mRNA and protein in lung tissue in group C at 21st d and 34th d were significantly higher than those in group A at 21st d and 34th d ［21st d:(0.84±0.09)mmol/L vs 0.57±0.10)mmol/L, (2.39±0.14)mmol/L vs (2.11±0.08) mmol/L,(0.75±0.09)pmol/g vs (0.59±0.06)pmol/g, (88.50±8.50)pmol/g vs (60.10±7.70)pmol/g, P<0.05, respectively; 34th d:(0.67±0.10)mmol/L vs (0.51±0.09)mmol/L, (2.17±0.08)mmol/L vs (2.05±0.09)mmol/L,(0.61±0.05)pmol/g vs (0.53±0.06)pmol/g, (76.60±7.10)pmol/g vs (58.00±7.60)pmol/g, P<0.05, respectively］. Also, plasma Mg2+, intracellular Mg2+, the beta 2-AR, mRNA and protein of lung tissue in group D at 21st d and 34th d were significantly higher than those in group B at 21st d and 34th d ［21st d:(0.95±0.33)mmol/L vs (0.46±0.09)mmol/L,(2.32±0.18)mmol/L vs (1.87±0.14)mmol/L,(0.73±0.10)pmol/g vs (0.43±0.07)pmol/g, (96.90±8.00)pmol/g vs (47.90±4.90)pmol/g, P<0.05, respectively; 34th d:(0.71±0.10)mmol/L vs (0.31±0.08)mmol/L, (1.66±0.13)mmol/L vs (1.45±0.16)mmol/L,(0.40±0.07)pmol/g vs (0.33±0.05)pmol/g, (61.50±3.20)pmol/g vs (35.30±7.10)pmol/g, P<0.05, respectively］.CONCLUSION: The expression of β2-adrenergic receptor mRNA in the lung of C57BL/6 asthmatic mice with deficient intracellular magnesium is suppressed and C57BL/6 asthmatic mice with deficient intracellular magnesium are even easier to induce downregulation of β2-adrenergic receptor when β2-AR agonist is administered.     

Changes of adiponectin and adiponectin receptor 1 in diabetic rats of different courses during myocardial ischemic preconditioning

AIM: To investigate the different effects of adiponectin (APN) and adiponectin receptor 1 (Ad-R1) on myocardial ischemia-reperfusion (IR) injury and ischemic preconditioning (IPC) in different course of diabetic rats in vitro. METHODS: The rat models of type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) were successfully established using streptozotocin and high-fat diet plus streptozotocin, respectively. These rats were divided into 2 groups:4 weeks and 8 weeks. The model of isolated cardiac perfusion was established by Langendorff method. Each group was further divided into control (Con) group, IR group and IPC group. The activity of lactate dehydrogenase (LDH) and creatine kinase (CK) in coronary effluent was detected. The serum and myocardial levels of APN were determined by ELISA. The expression of Ad-R1 in the myocardial tissues was detected by Western blot. The area of myocardial infarction was detected, and the ultrastructure of ventricular papillary muscle was observed by transmission electron microscopy. RESULTS: Compared with the corresponding IR group, the activity of LDH and CK in the IPC group at 4 weeks was significantly decreased (P<0.01), and the area of myocardial infarction was significantly reduced. However, no significant difference of each index in DM groups at 8 weeks was observed. Serum APN level was decreased in diabetic rats, especially in T2DM rats (P<0.05). The levels of APN and Ad-R1 in myocardium of normal rats had no difference among Con, IR and IPC groups. The level of APN in myocardium of T1DM rats had no difference in all subgroups, while the expression of Ad-R1 in myocardial tissue of IR group was significantly increased as compared with Con group (P<0.01) and IPC group (P<0.01) both at 4 and 8 weeks. In T2DM rats, the levels of APN in myocardium both at 4 and 8 weeks were decreased in IR group compared with Con group (P<0.05). The level of APN in IR group at 4 weeks was significantly decreased compared with IPC group, but had no significant difference at 8 weeks. The expression of Ad-R1 in myocardial tissue of IR group was significantly increased compared with Con group (P<0.05) both at 4 and 8 weeks. The level of Ad-R1 in IR group at 4 weeks was significantly increased compared with IPC group (P<0.05), but had no significant difference at 8 weeks. CONCLUSION: The protective effect of IPC exists in diabetic rats at 4 weeks, whereas it disappears at 8 weeks. APN and Ad-R1 in myocardium were probably involved in the protective effect of IPC on T2DM rats.     

Effect of berberine on oxidative damage and the SIRT1/p53 pathway in liver tissues of NAFLD rats

AIM:To investigate the effect of berberine on oxidative damage and silent mating type information regulation 2 homolog 1 (SIRT1)/p53 pathway in the liver tissues of nonalcoholic fatty liver disease (NAFLD) rats and to explore the mechanism of berberine against NAFLD. METHODS:The male SD rats (n=24) were randomly divided into normal group, model group and berberine group (8 rats in each group). The rats in normal group was fed with normal diet, while the rats in model group and berberine group were fed with high-fat diet. The rats in berberine group was intragastrically administered with daily doses (100 mg/kg) of berberine for 16 weeks. The levels of liver total cholesterol (TC), triglyceride (TG), superoxide dismutase (SOD), malondialdehyde (MDA) and total anti-oxidant capatity (T-AOC) were measured. HE staining, oil red O straining and transmission electron microscopy were used to observe the histological changes of the livers. The protein levels of SIRT1, p53 and acetylated p53 (Ac-p53) were determined by Western blot. RESULTS:Compared with model group, the levels of liver TC, TG and MDA in berberine group were significantly reduced (P<0.05 or P<0.01), and the levels of SOD and T-AOC were significantly increased (P<0.01). The results of pathological observation showed that the lipid accumulation in the liver of berberine group was significantly attenuated. Compared with model group, the expression of SIRT1 was significantly increased and the expression of Ac-p53 was obviously reduced in berberine group (P<0.01). CONCLUSION:Berberine reduces hepatic steatosis and oxidative damage in NAFLD rats induce by high-fat diet, and this effect may be associated with regulation of the SIRT1/p53 signal pathway.     

Effects of Retinervus luffae fructus on serum lipid level in experimental hyperlipidemia rats

AIM: To investigate effects of Retinervus luffae fructus (RLF) on level of serum lipid and body weight in hyperlipidemia rats. METHODS: Thirty-two male SD rats were randomly divided into four groups: control group (A), hyperlipidemia group (B), hyperlipidemia + RLF group (C), RLF group (D). Both group A and C were fed normal diet every day, while group B and group D fed high fat diet. Meanwhile, group C and D were administered with RLF solution at the dose of 10 mL/kg, respectively for 14 days, while group A and B were administered with drinking water. RESULTS: (1) At the end of experiment, a significant reduction was found in the levels of serum total cholesterol (TC) and triglyceride (TG) of group C animals treated with RLF solution; (2) The levels of serum TC of group D was progressively decreased compared to the level of serum TC at the beginning of experiment; (3) The level of high-density lipoprotein cholesterol (HDL-C) of group C remained unaltered 8d after treatment with RLF solution; (4) The body weight in group C was obviously lower than that in group B. CONCLUSION: RLF had an obvious hypolipidemic effect on hyperlipidemia rats. It can inhibit the decrease in the HDL-C and the increase of body weight in rats.     

Effect of hyperlipidemia and influence of simvastatin on endoplasmic reticulum stress in rat kidney

AIM: To investigate the role of endoplasmic reticulum stress in renal injury caused by hyperlipidemia and the influence effect of simvastatin. METHODS: Thirty male Wistar rats were randomly divided into three groups: rats in control group (n=10) were fed with normal diet; rats in high fat group (n=10) were fed with high fat diet; animals in simvastatin+high fat group (n=10) were fed with high fat diet and were received simvastatin 10 mg·kg-1·d-1 by gastric irrigation. After 18 weeks, the quantitative urine protein in 24 h, the serum cholesterol and triglycerides levels were tested. The pathological changes of renal tissue were observed under optic microscope. The expressions of GRP78 and p-JNK in renal tissues were examined by immunohistochemistry. The apoptotic cells in the kidney were detected by TUNEL staining. The mRNA expressions of GRP78 and CHOP were examined by RT-PCR. RESULTS: The quantitative urine protein in 24 h, the serum lipid, the expressions of GRP78 and p-JNK proteins, the mRNA expressions of GRP78 and CHOP as well as the apoptotic cells in renal tissues were increased in high fat group (P<0.01).The quantitative urine protein in 24 h, the serum lipid, the expression of GRP78 and p-JNK proteins, the mRNA expressions of GRP78 and CHOP as well as the apoptotic cells in renal tissues were remarkably reduced in simvastatin+high fat group than those in high fat group (P<0.05). CONCLUSION: The endoplasmic reticulum stress is engaged in the renal injury caused by hyperlipidemia. The simvastatin play a role in renal protection by inhibiting the endoplasmic reticulum stress in the kidney.     

Effects of eplerenone on expression and activity of aortic endothelial nitric oxide synthase in hypertensive rats induced by high-salt intake

AIM: To explore the effects of eplerenone on the expression and activity of aortic endothelial nitric oxide synthase(eNOS) in high salt-induced hypertensive rats.METHODS: Male Wistar rats(4 week old, weighting 50～60 g) were randomly divided into control group, high-salt diet group and eplerenone group. The rats in control group were fed with ordinary rodent animal diet, the rats in high-salt group and eplerenone group were exposed to 5% salt diet for 16 weeks and administrated with the same dosage of saline or eplerenone(40 mg·kg^-1·d^-1) by gavage for 4 weeks, respectively. Systolic blood pressure(SBP) was measured by tail-cuff every 2 weeks. The rats were sacrificed after 16 weeks and the thoracic aorta was collected. The aldosterone content in the aorta was measured by ELISA. The protein levels of mineralocorticoid receptor(MR) and eNOS were determined by Western blot. The activitie of constitutive NOS(cNOS) was measured by chemocolorimetry. The protein localization of eNOS, neuronal nitric oxide synthase(nNOS) and MR was observed by immunohistochemistry.RESULTS: A process of 8-week high-salt diet increased SBP gradually. SBP in the rats exposure to high salt for 16 weeks was significantly higher than that in control group(P<0.05). After 4 weeks of eplerenone treatment, SBP in the rats was significantly lower than that before treatment(P<0.05). Compared with control group, the aldosterone content in the aorta were significantly increased in high-salt diet group and eplerenone group(P<0.05), the expression level of MR also increased significantly(P<0.05). Compared with control group, both eNOS protein expression(P<0.05) and cNOS activity in high-salt diet group were significantly decreased(P<0.05). The protein expression of eNOS as well as cNOS activity in aorta increased significantly in eplerenone group compared with high-salt diet group(P<0.05).CONCLUSION: Aldosterone content in aorta of high-salt-induced hypertensive rats increases significantly. Aldosterone attenuates the protein expression of eNOS and reduces the enzyme activity through the activation of mineralocorticoid receptor. The selective mineralocorticoid receptor antagonist eplerenone enhances the protein expression of eNOS and its activity, thereby improves eNOS function.     

Role of EETs downregulation in obesity-related hypertension induced by a high fat diet

AIM: To study the effect of renal epoxyeicosatrienoic acids (EETs)on juvenile rats with obesity related hypertension induced by high fat diet.METHODS: Sprague-Dawley male rats were fed with high fat diet from 3-week old. The changes of weight and sBP between the rats of high fat diet and normal diet were compared. EETs activity was analyzed with RP HPLC and Western blotting in different parts of kidney.RESULTS: Weight and sBP increased in high fat diet group at the eighth and eleventh weeks ［(328±23)g vs (273.0±21.0)g, (153.0±8.6)mmHg vs (134.0±7.7)mmHg, P<0.05］. No significant change of the EETs activity of renal microvessels between two groups was observed. The EETs activity in cortex and papilla decreased in high fat diet group compared with that in normal diet group ［(75.4±9.2)nmol·g-1·min-1 vs (138.1±10.3)nmol·g-1·min-1, (55.8±6.2)nmol·g-1·min-1 vs (121.6±11.3)nmol·g-1·min-1, P<0.05］, and this was confirmed by Western blotting.CONCLUSION: These results demonstrate that juvenile rats with obesity related hypertension induced by high fat diet might be related to the downregulation of EETs activity in cortex and papilla.     

Effect of simvastatin on expression of integrin-linked kinase and renal tubulointerstitium injury in rats induced by high fat diet

AIM: To explore the effect of simvastatin on expression of integrin-linked kinase (ILK) and the injury of renal tubulointerstitium in the rats induced by high fat diet. METHODS: Fifty-four 6-8 week-old female Wistar rats were randomly assigned to the following three groups: high fat diet group, simvastatin group (rats were fed with high fat diet plus 10 mg·kg-1·d-1 simvastatin) and control group. Six rats in each group were sacrificed at 4th week, 10th week, and the others at 20th week. The injury of renal tubulointerstitium was observed under microscope with HE staining and the expression of renal ILK was determined by Western blotting analysis and immunohistochemistry. Levels of total cholesterol (TC) and triglyceride (TG) in serum were measured by enzymatic colormetric methods. RESULTS: The serum TC and TG levels and the expression of renal ILK significantly increased in both high-fat diet group and simvastatin group, compared to control group at 4th week, reaching a maximum at 20th week (P<0.01). Tubulointerstitium injuries including vacuolar degeneration, syncytial change, clody swelling, necrosis and atrophy of renal tubular epithelial cells, thinning of tubal wall, lumens compensational expansion or even abolition, and inflammatory cell infiltration, interstitial fibrosis were found in both high fat diet group and simvastatin group, compared to control group at 4th week, worsened to a maximum at 20th week. However, all of these ameliorated in simvastatin group, compared to high fat diet group at each time point. CONCLUSION: The results indicate that high-fat diet induces significant lesion of renal tubulointerstitium and increased expression of renal ILK. Simvastatin may play an important role in protecting against tubulointerstitium injury induced by hyperlipoidemia by down-regulating the expression of renal ILK.     

Effect of high-fructose diet on adipose tissue renin-angiotensin system in rats

AIM: To observe the effects of high-fructose diet on adipose tissue inflammation and renin-angiotensin system (RAS), and to reveal the role of Toll-like receptor 2 (TLR2) in this process.METHODS: Male SD rats (n=16) were randomly divided into control group, high fructose group, high fructose+siRNA negative control group, and high fructose+TLR2-siRNA group. The rats in control group were fed with a standard chow diet. The rats in high fructose group were fed with a diet with 60% fructose, and the rats in high fructose+TLR2-siRNA group and high fructose+siRNA negative control group were transfected with TLR2 siRNA and scrambled siRNA, respectively. Serum uric acid was measured and visceral adipose tissue was weighed at the 14th week. The levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), angiotensinogen (AGT), and angiotensin Ⅱ (Ang Ⅱ) were measured by ELISA. Infiltrating macrophages in the adipose tissues were measured with immunohistochemistry. The mRNA expression of IL-6, TNF-α, monocyte chemoattractant protein-1 (MCP-1), AGT, angiotensin-converting enzyme 1 (ACE1), angiotensin Ⅱ type 1 receptor (AT1R), and angiotensin Ⅱ type 2 receptor (AT2R) was detected by RT-qPCR. The protein level of TLR2 was determined by Western blot.RESULTS: High fructose-fed rats showed elevated serum uric acid, raising fat content, higher serum concentrations of IL-6, TNF-α, AGT and AngⅡ, and more infiltrating macrophages in the adipose tissues (P<0.05). Moreover, the mRNA levels of IL-6, TNF-α,MCP-1, AGT, ACE1, AT1R and AT2R in the adipose tissues were increased (P<0.05). When high fructose-fed rats were transfected with TLR2-siRNA, the dramatic decreases in TLR2 protein level and number of infiltrating macrophages in the adipose tissues were found. Both in serum and adipose tissues, the mRNA levels of inflammatory cytokines and RAS components were all significantly decreased (P<0.05).CONCLUSION: High-fructose diet up-regulates RAS in adipose tissues via activation of TLR2 inflammation signaling pathway.     

Effects of glycine on insulin resistance and cognitive impairment induced by high-fructose diet

AIM: To investigate the role of intestinal endotoxemia (IETM) in insulin resistance (IR) and cognitive impairment, and to explore the protective mechanisms of glycine in rats with high-fructose diet. METHODS: The rats in model group were fed with 8% fructose water, and the rats in intervention group were fed with water containing 8% fructose and 1% glycine. The body weight and systolic pressure were measured monthly. After 8 months, plasma glucose, plasma lipids, glucose tolerance and plasma endotoxin (LPS) were detected. Plasma insulin, pro-inflammatory cytokines in plasma and cerebral cortex were determined by ELISA, and HOMA-IR was also calculated. The molecules of insulin signaling pathway in cerebral cortex were determined by Western blotting. The cognitive functions of the rats were tested by Morris water maze. RESULTS: The weight gain in model group was increased from the 3rd month to the 6th month, and systolic pressure was increased after the 3rd month as compared with control group. Glycine significantly reduced the weight gain in the 4th month and the 6th month, and significantly reduced the systolic pressure from the 4th month to the 6th month. Meanwhile, glycine partly attenuated dyslipidemia and glucose intolerance, and lowered the levels of plasma LPS, plasma insulin, HOMA-IR and pro-inflammatory cytokines in plasma and cortex. Furthermore, glycine attenuated the abnormal expression of insulin signaling proteins and cognitive impairment. CONCLUSION: Long-term fructose diet induces the rats to peripheral and neuronal IR, which accompanies IETM and low-grade inflammation. Glycine attenuates IR and cognitive impairment by lowering IETM.     

The alteration of expression of iNOS mRNA and ecNOS mRNA in peripheral leukocytes from insulin resistance rats fed with fructose

AIM: To study the alteration of expression of iNOS mRNA and ecNOS mRNA in peripheral leukocytes of Wistar rats fed with fructose. METHODS: Wistar rats were randomly divided into the control group (n=10) and the fructose feeding group(n=10). The fructose feeding group drank12% fructose water for 6 months. The blood glucose, blood insulin, and the expression of iNOS mRNA and ecNOS mRNA in peripheral leukocytes of rats were determined. RESULTS: The levels of blood insulin (P<0.01) and the expression of ecNOS mRNA were higher in fructose feeding group than that in control group after1month. The level of blood insulin(P<0.01), the level of blood glucose (P<0.05), the expression of ecNOS mRNA and the iNOS mRNA were also higher in fructose feeding group than that in control group after 2 months. The levels of blood insulin and glucose, the expression of ecNOS mRNA and the iNOS mRNA were increased persistently during 3 to 6 months. CONCLUSIONS: These results indicate that fructose can increase the level, but reduce the sensitivity of insulin. It can also induce the expression of ecNOS mRNA firstly and the expression of iNOS mRNA secondly, the former can delay the formation of insulin resistance and the later can accelerate the formation of insulin resistance.     

Mechanism of hepatic insulin resistance induced by high-fat diet

AIM: To observed the relationship between oxidative stress and development of insulin resistance in hepatic tissues of Sprague dawley(SD) rats by analyzing reactive oxygen species(ROS) level and NADPH oxidase 3(NOX3) expression in livers. METHODS: Four-week-old male SD rats were fed with high-fat diet containing 20% fat and 20% sucrose for 12 weeks to induce insulin resistance. Plasma insulin level was detected by radioimmunoassay. The content of liver intracellular glycogen was measured using a glycogen assay kit. ROS generation in the liver tissues was assessed by dihydroethidium(DHE) fluorescence. The expression of NOX3 was determined by Western blotting.RESULTS: After 12 weeks of high-fat diet feeding, the content of blood glucose was increased but still maintained in normal level in the rats. However, the index of insulin sensitivity obviously decreased. Hepatic glycogen content in the rats fed with high-fat diet was significantly decreased, indicating that insulin resistance developed. Enhanced ROS production in hepatic tissues of the rats fed with high-fat diet was observed. Importantly, the expression of NOX3 in the liver was up-regulated in response to high-fat diet in vivo.CONCLUSION: High-fat diet feeding decreases insulin sensitivity, enhances ROS level and NOX3 expression, and reduces glycogen content in the livers.     

Correlation of serum omentin-1 level and insulin resistance in rats

AIM：To establish the insulin resistance rat model for evaluating the correlation of omentin-1 level and insulin resistance. METHODS：SPF male Wistar rats (n=30) were randomly divided into normal control group (NC, n=15) and high-fat diet group (HF, n=15). The rats in NC group were fed with basic diet. The insulin resistant model was established by feeding the rats with high-fat diet in HF group. After 10 weeks, 5 rats in each group were assessed by the technique of hyperinsulinaemic-euglycaemic clamp. After the insulin resistant model was successfully established, the body weight and fasting blood glucose were detected. The concentration of fasting serum omentin-1 was analyzed by ELISA. Fasting serum insulin was measured by radioimmunoassay. RESULTS：No difference of fasting blood glucose between the 2 groups was observed. The level of fasting serum insulin in HF group was significantly higher than that in NC group (P<0.05). The level of serum omentin-1 in HF group were significantly decreased compared with NC group (P<0.01). Pearson’s correlation analysis showed that negative correlations between serum omentin-1 and fasting serum insulin (r=-0.654,P<0.01), serum omentin-1 and free fatty acid (r=-0.446, P<0.05) was found. CONCLUSION：In rats, serum omentin-1 level began to decrease at insulin resistance stage. As serum omentin-1 level decreased, the basal insulin level increased, indicating that decreased serum omentin-1 level may be an early factor of IR, diabetes and cardiovascular diseases.     

Dexmedetomidine reduced isoflurane-induced neuroapoptosis by inhibiting activation of p38 and JNK proteins in hippocampus of neonatal rats

AIM：To investigate the effect of dexmedetomidine (Dex) on neuronal apoptosis induced by isoflurane (Iso) and its relationship with the expression of p38 mitogen-activated protein kinase (p38) and c-Jun N-terminal kinase (JNK) proteins in the hippocampus of neonatal rats. METHODS：Forty-eight neonatal SD rats at postnatal day 7 were randomly divided into control group (Con), Dex group, Iso group and Iso combined with Dex (Iso+Dex) group. Rats in Iso and Iso+Dex groups were exposed to 0.75% Iso for 6 h, while rats in Con and Dex groups were exposed to air for 6 h. Rats were intraperitoneally injected with 25 μg·kg-1 Dex (Dex and Iso+Dex groups) or 150 μL saline (Con and Iso groups) 20 min before exposure and 2 and 4 h after exposure. After the termination of anesthesia, the neuronal apoptosis in hippocampal CA1 region was detected by TUNEL staining, and the protein expression of cleaved caspase-3, phospho-p38 (p-p38), p38, phospho-JNK (p-JNK) and JNK in hippocampal tissues was detected by Western blotting. RESULTS：The number of TUNEL positive cells in hippocampal CA1 region of the rats in Iso group was increased by 447.57% (P<0.01) compared with Con group, while Dex significantly inhibited the increased TUNEL positive cells in Iso group by 75.18% (P<0.01). The expression of cleaved caspase-3 protein in Iso group was increased by 126.29% (P<0.01) compared with Con group, while Dex reversed the increased cleaved caspase-3 protein expression (P<0.01). Iso significantly increased the phosphorylation of p38 and JNK proteins (P<0.01), while Dex reversed the increased p-p38 and p-JNK proteins (P<0.01). CONCLUSION：Dex attenuates Iso-induced neuroapoptosis in the hippocampus of neonatal rats through inhibiting the phosphorylation of p38 and JNK proteins.     

Effect of caveolin-1 expression on high-salt diet-induced endothelial dysfunction in type 1 diabetic rats

AIM: To investigate the underlying mechanisms responsible for endothelial dysfunction of type 1 diabetes mellitus (DM) rats fed with high-salt diet. METHODS: Type 1 DM was induced by intraperitoneal injection of streptozotocin (70 mg/kg). Normal and diabetic rats were fed high-salt food (HS, 8% NaCl) and standard food for 6 weeks, respectively. Isometric tension of the mesenteric arteries were measured. The expression of Akt, endothelial nitric oxide synthase (eNOS) and caveolin-1 (Cav-1) was examined by Western blot. RESULTS: The rats in DM+HS group exhibited more pronounced impairment of vasorelaxation to acetylcholine and insulin compared with either DM group or HS group (P<0.01). Akt and eNOS phosphorylation levels, and nitric oxide (NO) concentration in DM+HS group were significantly lower than those in DM group (P<0.01). The level of Cav-1 in DM+HS group was significantly higher than that in DM group and HS group. CONCLUSION: Impaired endothelial Akt activation, increased Cav-1 expression and resultant decreased eNOS activation contribute to aggravate high-salt diet-induced endothelial dysfunction and hypertension in DM rats.     

Effect of calories restriction on ER stress in the liver of high fat diet rats

AIM: To study the effect of calories restriction on endoplasmic reticulum(ER) chaperone protein 78-kD glucose regulated protein (GRP78) mRNA expression in the liver of high fat diet rats, in order to explore the mechanism of how calories restriction improves insulin resistance. METHODS: Wistar rats (n=24) were randomly divided into 3 groups: normal chow (NC) group, was fed free normal chow (18.94% of calories as fat) for 12 weeks; high fat group (HF) was fed high fat diet (50.55% of calories as fat) for 12 weeks; calories restriction group (CR) was fed high fat diet for 8 weeks at first, then given 50% of diet consumed by the same age NC group. Changes of body weight, height, and food intake were recorded. At the end of experiment, HOMAIR, the rate of visceral fat (including perirenal fat and epididymal fat) vs weight, plasma protein, blood lipid (including total cholesterol and triglyceride), hepatic GRP78 mRNA and hepatic histological changes (including light microscopic studies and electron microscopic studies) were detected. RESULTS: (1) Animals in HF group had an obviously elevation of fasting insulin (27.51±3.51) mU/L vs (15.46±2.25) mU/L, triglyceride (1.35±0.25) mmol/L vs (0.67±0.10) mmol/L, total cholesterol (2.59±0.34) mmol/L vs (1.41±0.28) mmol/L and insulin resistance index HOMAIR (5.85±0.23 vs 2.85±0.60) compared with NC group, and also had obviously lipid accumulations in the liver. (2) After calories restriction, all the abnormal elevated biochemical indicators were decreased to normal levels, the hepatic lipid accumulations were also improved. (3) The changes of liver ultrastructure in HF group showed rough endoplasmic reticulum enlargement, fragmentation, taking off grain, and with glycogen solution. The changes in CR group were nearly the same as those in NC group. (4) High fat diet induced the expression of GRP78 mRNA, calories restriction might reverse it. CONCLUSION: Reasonable food calories restriction is a good method to improve insulin resistance, partly due to improvement of endoplasmic reticulum stress in liver.     

Effect of polygonum cuspidatum and hawthorn on anti-atherosclerosis unstable plaque

AIM: To investigate the effect of detoxifying herbs polygonum cuspidatum, and hawthorn, herb of promoting blood flow, on pathologic morphology and inflammatory factors in apolipoprotein E gene knockout mice, in order to approach the possible regulatory mechanism of polygonum cuspidatum and hawthorn for treating artherosclerosis (AS) unstable plaque. METHODS: The animals were divided into 7 groups (12 mice in every group). The ApoE (-/-) mice fed with high fat diet were divided into polygonum cuspidatum group, hawthorn group, polygonum cuspidatum + hawthorn group, Xuezhikang group and high fat diet model group. Moreover, ApoE (-/-) mice fed with normal diet (normal diet group) and C57BL/6J mice fed with normal diet (normal control group) were set up. After intragastric administration for 17 weeks, serum hs-CRP was detected, aorta structure was observed under light microscope and NF-κB protein expression was determined by immunohistochemistry. RESULTS: The pathological change of AS in aorta in all groups fed with high fat diet and normal diet group were observed with different degree. The changes of aortic lesion in all treatment groups were reduced. The levels of NF-κB and hs-CRP in high fat diet group were significant higher than those in normal control group and normal diet group. Serum NF-κB and hs-CRP levels decreased in every treatment group, which were significant different from those in high fat diet model group (P<0.01). Among them, the changes in polygonum cuspidatum and hawthorn groups were the best. CONCLUSION: Chinese herbs of polygonum cuspidatum and hawthorn reduce inflammatory factors NF-κB and hs-CRP expression and play a role in anti-AS formation.