Effect of BQ123 on the voltage-gated K+ current of pulmonary artery smooth muscle cells of rats exposed to chronic hypoxia

AIM:To study the effect of BQ123 on voltage-gated K+ current in pulmonary artery smooth muscle cells (PASMCs) from chronic hypoxic rats. METHODS:Twelve age and body weight matched Wistar rats were randomly divided into control and chronic hypoxic group. Single PASMCs were obtained with acute enzyme (collagnaseⅠ plus papain) dispersing method. Using the whole cell patch-clamp technique in freshly isolated PASMCs from normorxic and hypoxic rats, the effects of ET-1 and BQ123, a selective ETA receptor antagonist, on voltage-gated K+ current were recorded. RESULTS:(1) ET-1 (10-8 mol·L-1) caused inhibition of K+ current in PASMCs from normoxic and hypoxic rats. The effect of ET-1 on K+ current in PASMCs from hypoxic rats was greater than that from normoxic rats ［+50 mV, percent inhibition were (71.04±6.58)% and (60.21±5.32)%, respectively, P<0.01, n=6］. (2) In normoxic PASMCs, neither BQ123 alone produced influence on the IKV (P>0.05, n=5), nor ETA receptor blockade had change of ET-1 mediated IKV inhibition. (3) In chronic hypoxic PASMCs, BQ123 significantly reduced the effect of ET-1 mediated IKV inhibition, from (28.49±6.69) pA/pF to (74.19±9.74) pA/pF at +50 mV (P<0.01, n=6). CONCLUSION:In normoxic condition, the effect of ET-1 on IKV of PASMCs is not mediated by BQ123, a selective ETA receptor antagonist. During exposure to chronic hypoxia, the inhibition of ET-1 on IKV of PASMCs is partly mediated by BQ123, namely, ETA receptor mediates the effect of ET-1 on IKV of chronic hypoxic PASMCs.     

The protective effects of angiotensin Ⅱ receptor blocker irbesartan on kidney function in diabetic rats

AIM: To investigate the effects and mechanisms of irbesartan, one of the angiotensin Ⅱreceptor blockers, on kidney function in diabetic rats. METHODS: Forty adult male Wistar rats were randomly divided into four groups: control group, diabetes group, irbesartan group and captopril group. At the end of 12 weeks, the rats were sacrificed. Urine volume, body weight, kidney weight/body weight, plasma, glucose, glycosylated hemoglobin (HbA₁c), urinary β₂-microglobulin (β₂-MG) excretion, urinary albumin excretion rate (UAR), creatinine clearance (Ccr) were measured. Nitric oxide (NO) and endothelin-1 (ET-1) levels in plasma, urinary and renal tissues were determined. RESULTS: Urine volume, kidney weight/body weight, plasma glucose, HbA1C, UAR, Ccr, urinary β₂-MG excretion, NO and ET-1 levels of urinary, blood and renal tissue in diabetic rats were significantly higher than those of normal controls ( P<0.01). UAR, Ccr, urinary β₂-MG excretion, ET-1 and NO levels of urinary and renal tissue in rats of irbesartan and captopril groups were significantly lower than those of DM rats ( P<0.01). There were positive relationships among the levels of plasma, urinary, renal tissue ET-1, NO and UAR, Ccr and urinary β₂-MG excretion. CONCLUSION: Irbesartan could prevent from the injury of renal function in STZ-induced diabetic rats. And it maybe one of the most importan mechanisms that irbesartan could reduce the NO and ET-1 levels in STZ-induced diabetic rats.     

Effect of N-acetyl-L-cystein on blood pressure and endothelial function in aorta of rats exposed to chronic intermittent hypoxia

AIM: To investigate the effect of N-acetyl-L-cystein (NAC) on blood pressure and endothelial function in the aorta of the rats exposed to chronic intermittent hypoxia (CIH). METHODS: Thirty healthy male SD rats were randomly divided into 3 groups: control group, CIH group and CIH+NAC group. The systolic blood pressure (SBP) was measured with tail-cuff me-thod. Real-time fluorescence quantitative polymerase chain reaction (qRT-PCR) was used to detect the mRNA expression of endothelial nitric oxide synthase (eNOS） and endothelin-1 (ET-1) in the thoracic aorta. The protein expression of eNOS in the thoracic aorta was examined by Western blotting. The levels of ET-1 in the thoracic aorta and serum were detected by radioimmunoassay. The serum nitric oxide was determined by nitric acid reduction method.The superoxide dismutase (SOD) activity in peripheral blood plasma was detected by xanthine oxidase method.The serum malondialdehyde content was detected by thiobarbituric acid method, and superoxide anion (O-·2) in thoracic aorta was determined by chemical colorimetric method. RESULTS: Compared with the control animals, CIH exposure was associated with decreased SOD level, and NAC-treated CIH animals showed recovery in SOD level. NAC treatment prevented CIH-induced hypertension as well as CIH-induced increase in MDA. The aorta eNOS mRNA and protein, and serum NO levels in CIH group were lower than those in control group, and those in NAC treatment group were higher than those in CIH group. The increases in ET-1 mRNA,ET-1 protein and O-·2 levels in the aorta, and the elevated circulating ET-1 level were also observed in CIH-exposed animals. Treatment with NAC significantly decreased the mRNA and protein levels of ET-1, the O-·2 content, and the circulating ET-1 level in CIH-exposed animals. CONCLUSION: NAC protects endothelial function and alleviates hypertension by suppressing the oxidant stress in the aorta tissues, indicating that oxidant stress may be involved in the mechanism of endothelial disorder of CIH-induced hypertension.     

Effect of mesenteric lymph duct ligation on actue lung injury in rats

AIM：To explore the effect of mesenteric lymph duct ligation against actue lung injury (ALI) in rats.METHODS：45 Wistar rats were divided into three groups：the ligation group,the non-ligation group and sham operated group,and the two-hit model was established by hemorrhage and LPS injection.Mesenteric lymph was diverted by ligating mesenteric lymph duct in ligation group.All rats facilitated blood withdrawal for blood sample to arterial gas analysis after 24 hours.Then the WBC,NO,NOS,MDA,SOD and lung permeability index (LPI) were determined in bronchoalveolar lavage fluid (BALF),the MPO and ATPase activity were determined in lung homogenate.The ultrastructure was also observed.RESULTS：After two-hit,the PaCO2,the total cells and PMN,the NO2-/NO3-,NOS and MDA content in BALF and MPO activity in lung homogenate and LPI in non-ligation group were significantly increased than those in sham operated group.PaO2 and pH in arterial blood,SOD in BALF and the ATPase in lung homogenate were significantly lower (P<0.01 or P<0.05).The total cells and PMN,MDA,NO2-/NO3- in BALF,LPI in ligation group were significantly increased than those in sham operated group,and SOD in BALF was significantly lower (P<0.01 or P<0.05).The pH and PaO2 in arterial blood,the ATPase in lung homogenate in ligation group were significantly increased than those in non-ligation group,and the PaCO2,the total cells,PMN,NO2-/NO3-,NOS,MDA in BALF,LPI,and MPO in lung homogenate in ligation group were significantly lower than those in non-ligation group (P<0.01 or P<0.05).The injury of pulmonary vascular endothelium in ligation group was lighter than that in non-ligation group.CONCLUSION：The ligation of mesenteric lymph duct attenuates the ALI of rats.Mesenteric lymph might play an important role in the pathogenesis of ALI.     

Impact of hydrogen sulfide donor on endothelin-1 and connective tissue growth factor expression in rats with pulmonary hypertension induced by high pulmonary blood flow

AIM: To explore the possible impact of hydrogen sulfide (H2S) donor-sodium hydrosulfide (NaHS) on endothelin-1 (ET-1) and connective tissue growth factor (CTGF) expressions in rats with pulmonary hypertension induced by high pulmonary blood flow. METHODS: Thirty-two male SD rats were randomly divided into 4 groups: shunt group, shunt+NaHS group, sham group and sham+NaHS group. Rats in shunt group and shunt+NaHS group were subjected to an abdominal aorta-inferior vena cava shunt to create an animal model of high pulmonary flow. After 11 weeks of experiment, rat systolic pulmonary artery pressure (SPAP), lung tissue H2S, plasma ET-1 concentration and lung tissue ET-1mRNA expression, as well as pulmonary artery CTGF protein expression were detected.RESULTS: After 11 weeks of experiment, SPAP, lung tissue ET-1mRNA, plasma ET-1 as well as pulmonary artery CTGF expressions were increased markedly, respectively, whereas H2S in lung tissue decreased significantly in rats of shunt group as compared with that in sham group (all P<0.05). After administration of NaHS for 11 weeks, H2S in lung tissue increased significantly, whereas SPAP, plasma ET-1 and lung tissue ET-1 mRNA expression as well as pulmonary artery CTGF protein expression decreased significantly, respectively, in rats of shunt+NaHS group as compared with that in shunt group (all P<0.05).CONCLUSION: NaHS might be involved in the development of pulmonary hypertension induced by high pulmonary blood flow by down-regulating vasoactive peptides ET-1 and CTGF expressions in lung tissues of rats.     

Levels of CGRP and ET-1 in plasma of pulmonary artery and thoracic aorta and in the extractives of lung and ventricular tissues of the chronic hypoxic rats

AIM AND METHODS: To explore the effects calcitonin gene-related peptide (CGRP) and endothelin-1(ET-1) on the mechanisms of hypoxic pulmonary hypertension (HPH), the contents of CGRP and ET-1 in plasma of pulmonary artery and thoracic aorta and in extractives of lung and ventricular tissues of the chronic hypoxic rats were determined by radioimmunoassay. The changes of their hemodynamic indices and right heart hypertrophy index were monitored simultaneously. RESULTS: The level of pulmonary artery plasma CGRP was significantly higher than that of thoracic aorta plasma, but just the reverse was ET-1 or the ratio of ET-1 and CGRP in control rats( P<0.01). Compared with controls, the level of pulmonary artery plasma CGRP was gradually reduced in all hypoxic rats, but ET-1 was enhanced after 7 and 14 days of hypoxia and was decreased after 21 days of hypoxia. With prolonging time exposed to hypoxia, the level of thoracic aorta plasma CGRP was markedly increased in hypoxic animals compared with controls ( P<0.05), the positive correlation significantly with increased pulmonary arterial pressure( r = -0.896, P =0.05), but the lower level of thoracic aorta plasma ET-1 showed or negative correlation with pulmonary arterial pressure. CONCLUSIONS: These data suggest that the unbalance of effects of CGRP and ET may plays an important role in regulating the resistance of pulmonary circulation and has close relation with the formation of HPH.     

Effects of rAAV9-mediated siRNA for p65 knockdown on myocardial fibrosis and apoptosis in rats with pressure overload

AIM To investigate the effect of p65 gene knock-down mediated by recombinant adeno-associated virus serotype 9 （rAAV9） on the cardiac function of pressure overload rat and its possible mechanism. METHODS The rat model of left ventricular hypertrophy was established by abdominal aortic coarctation（AAC）. SD rats were randomly divided into sham operation group, AAC group, AAC+rAAV9-eGFP group and AAC+rAAV9-eGFP-P65-siRNA group. The abdominal cavity was closed directly after laparotomy in the rats of sham operation group, the abdominal cavity was closed after ligation of the abdominal aorta in the rats of AAC group, and normal saline, rAAV9-eGFP and rAAV9-eGFP-P65-siRNA were injected into the tail vein 3 d after operation. After 4 weeks, the hemodynamic indexes were measured, the heart mass parameters were calculated, the degree of myocardial fibrosis was detected by Masson staining, the expression level of myocardial P65 was detected by Western blot, the degree of apoptosis was detected by TUNEL staining, and the serum contents of tumor necrosis factor-α （TNF-α） and interleukin-6 （IL-6） of the rats in each group were measured by ELISA. RESULTS The expression of P65 in AAC group and AAC+rAAV9-eGFP group was higher than that in sham operation group, while the expression of P65 in AAC+rAAV9-eGFP-P65-siRNA group was significantly lower than that in AAC group. The levels of systolic blood prossure （SBP）, diastolic blood pressure （DBP）, left ventricular weight/body weight （LVW/BW）, cardiomyocyte apoptotic rate and TNF- α and IL-6 in AAC group and AAC+rAAV9-eGFP group were higher than those in sham operation group, while SBP, DBP, LVW/BW, cardiomyocyte apoptosis rate and TNF-α in AAC+rAAV9-eGFP-P65-siRNA group were significantly lower than those in AAC group. The results of Masson staining showed that the deposition of collagen in cardiac tissue in AAC group and AAC+rAAV9-eGFP group was higher than that in sham operation group, and treatment with rAAV9-eGFP-P65-siRNA alleviated hypertension-induced fibrosis. CONCLUSION Knockdown of p65 gene reduces the degree of left ventricular fibrosis and apoptosis in rats with stress overload, and its mechanism is related to the regulation of NF-κB pathway and the reduction of inflammatory response.     

Effects and mechanism of fenofibrate and pioglitazone on ventricular remodelingin in pressure overload rats

AIM: To study the effects and mechanism of peroxisome proliferator-activated receptors (PPARs) ligands,fenofibrate and pioglitazone,on ventricular remodeling in pressure overload rats.METHODS: A pressure overload model was established by the constriction of abdominal aorta in Wistar rats.The hemodynamics and ventricular remodeling parameters,plasma and myocardial renin activity,angiotensin Ⅱ and aldosteron,the mRNA expression of angiotensin Ⅱ type 1 receptor (AT1) were investigated in the constriction of abdominal aorta group (CAA group,n=7) at 12-week after operation and treated experimental groups in which rats were treated with fenofibrate (F group,n=8),pioglitazone (P group,n=7),concomitant fenofibrate and pioglitazone (F+P group,n=6) for 12 weeks since 2 days after operation.The sham-operated rats served as controls (n=8).RESULTS: The ratio of left ventricular weight to body weight,mean arterial pressure,left ventricular systolic pressure,left ventricular end diastolic pressure,left ventricular systolic pressure and heart rate were significantly lower,the maximum left ventricular pressure rising and declining rates(±dp/dtmax) were significantly higher in all treated experimental groups than those in CAA group.Fenofibrate or pioglitazone had no effect on plasma and myocardial levels of renin,angiotensin Ⅱand aldosteron.The mRNA expression of AT1 was downregulated in treated groups except F group.CONCLUSION: PPAR ligands have no effect on plasma and myocardial levels of renin,angiotensin Ⅱand aldosteron,but fenofibrate and pioglitazone inhibit ventricular remodeling,decrease preload and afterload,increase ±dp/dtmax in pressure overload rats.The expression of mRNA of AT1 is downregulated in myocardium of pressure overload rats by the PPARγ signaling pathway.     

Therapeutic effects of losartan and astragalus membranaceus on diabetic nephropathy

AIM: To observe the protective effects of losartan and astragalus membranace on the kidney of diabetic rats, and to study their possible mechanisms. METHODS: The diabetic rats were induced by a single intraperitoneal injection of streptozotocin. At the end of 12th week,changes in urinary albumin excretion, urinary β₂-MG excretion, Ccr,NO,ET-1 levels in blood, urinary and renal tissue were observed. Serum and urinary TGF-β₁ concentration,average volume of glomeruler,average thickness of glomerular basement membrane were also measured. RESULTS: In the treated diabetic rats, urinary albumin excretion, urinary β₂-MG excretion, Ccr, urinary and renal tissue NO, urinary TGF-β₁, average volume of glomeruler, average thickness of glomerular basement membrane decreased obviously as compared with diabetic untreated rats. These effects were enhanced when losartan was combined with astragalus membranace. CONCLUSION: Losartan or astragalus membranace reversed the injury of renal structure and function in STZ-induced diabetic rats. The protective effects were enhanced when losartan was combined with astragalus membranace. The decrease in NO,ET,TGF-β₁ concentration in renal tissue may be one of mechanisms for this action.     

Effects of atorvastatin on nitric oxide,endothelin-1 and myocardial function in a rabbit model of acute myocardial infarction and reperfusion

AIM: To evaluate the effects of atorvastatin on nitric oxide(NO), endothelin-1(ET-1)and myocardial no-reflow in a rabbit model of acute myocardial infarction and reperfusion(AMI/R). METHODS: Twenty-four rabbits were randomized into 3 groups: 8 in AMI/R group, 8 in atorvastatin-treated group(5 mg·kg-1·d-1)and 8 in sham-operated group. Animals in the former two groups were subjected to 60 min of coronary occlusion followed by 120 min of reperfusion. Data on haemodynamics were collected. NO in blood sample, and in normal, and in infarcted reflow and no-reflow myocardium were evaluated respectively by nitrate reductase method. The levels of ET-1 in blood sample, and in normal, infarcted reflow and no-reflow myocardium were determined by radioimmunoassay. RESULTS: (1)Compared to the baselines, the heart rate(HR), systolic blood pressure(SBP), diastolic blood pressure(DBP), left ventricular systolic pressure(LVSP), maximal rate of increase and decline in left ventricular pressure(±dp/dtmax)and cardiac output(CO)in AMI/R and atorvastatin-treated groups were significantly declined, whereas left ventricular end-diastolic pressure(LVEDP)was increased after 60 min of coronary occlusion and 120 min of reperfusion(P<0.05 or P<0.01). However, in atorvastatin-treated group, LVSP, LVEDP, ±dp/dtmax and CO at the time point of 120 min of reperfusion recovered more significantly than those at the time point of 60 min of coronary occlusion(P<0.01), which was more significant than those in AMI/R group(P<0.05 or P<0.01). Compared to AMI/R group, the SBP and DBP were significantly heigher in atorvastatin-treated group(P<0.01).(2)In atorvastatin-treated group, the levels of ET-1 in blood sample were significantly lower than those in AMI/R group(P<0.01), and the levels of NO were significantly higher(P<0.01). Moreover, the levels of NO or ET-1 in infarcted reflow myocardium were significantly lower than that in AMI/R group(P<0.05 or P<0.01).(3)Atorvastatin could ameliorate myocardial function. CONCLUSION: Atorvastatin is effective in increasing NO and reducing ET-1 in blood plasma and local myocardium, and in protection of endothelial cells. Atorvastatin also has a beneficial effect on improving left ventricular function during acute myocardial infarction and reperfusion in rabbits.     

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.     

Alleviation of aortic vascular dysfunction in STZ/HFD-induced type 2 diabetic rats by nFGF1

AIM: To investigate the protective effect of non-mitogenic fibroblast growth factor 1 (nFGF1) on the aortic vascular function in streptozotocin (STZ)/high-fat diet (HFD)-induced type 2 diabetic rats and its underlying mechanisms. METHODS: Five-week-old male SD rats (n=30) were randomly divided into 3 groups (n=10 in each group), including normal control group, type 2 diabetic group and nFGF1 treatment group (type 2 diabetic rats were intraperitoneally injected with 0.5 mg/kg nFGF1 every other day for 4 weeks). After the rats were sacrificed, blood glucose, cholesterol and triglyceride levels, aorta diastolic function and superoxide dismutase (SOD) level in the aorta of each group were measured. Besides, the protein levels of cyclooxygenase-2 (COX-2), phosphorylated extracellular signal-regulated kinase (p-ERK) and endothelial nitric oxide synthase (eNOS) in the aorta were determined by Western blot. RESULTS: nFGF1 markedly lowered blood glucose, cholesterol and triglyceride levels, enhanced aorta SOD activity and upregulated protein level of eNOS in the type 2 diabetic rats. Furthermore, the increased protein levels of COX-2 and p-ERK in the type 2 diabetic rats were largely abrogated by nFGF1. CONCLUSION: nFGF1 effectively attenuates aortic vascular dysfunction in the type 2 diabetic rats, which may be associated with decreasing blood glucose, cholesterol and triglyceride levels, reducing inflammation and oxidative stress response, and activating eNOS signaling pathway.     

Effect of heat shock protein 70 expression induced by glutamine on vascular hyporeactivity in rats caused by LPS

AIM: To observe the effect of heat shock protein 70(HSP70) expression induced by glutamine on Escherichia coli lipopolysaccharides(LPS)-induced vascular hyporeactivity in rats.METHODS: Twenty four healthy male Sprague-Dawley rats were randomly divided into: the control group (n=8);LPS shock group (n=8);glutamine(Gln) treated group (Gln 0.75 g·kg-1 iv,n=8).6 h after LPS shock,phenylephrine (PE,0.5-2.5 μg·kg-1 ) was applied intravenously to all groups and the percentage increase in mean arterial pressure(MAP) was detected,respectively.The concentration-response curves of aorta rings were obtained by cumulative addition of phenylephrine (PE),and PE Emax,EC50 were calculated.The blood concentration of malondialdehyde (MDA),TNF-α and IL-6 were assayed in all groups 30 min and 360 min after LPS shock,respectively.The expressions of HSP70 from heart and aorta were also assayed after 6 h LPS shock.RESULTS: The MAP level induced by PE significantly decreased by 51.4% in LPS shock group compared with the control (P<0.05).However,PE induced MAP level increased by 17.5% in Gln group compared with LPS shock group (P<0.05).Emax and EC50 to PE were significant reduced in LPS shock group compared with control group (P<0.05),but significantly improved in Gln group (P<0.05).The expressions of HSP70 from heart and aorta were much higher in Gln group than those in LPS shock group (P<0.05).The blood concentrations of TNF-α,IL-6 and MDA were much lower in Gln group than those in LPS shock group.CONCLUSION: Glutamine effectively improves α-adrenergic receptor-mediated vascular reactivity through inducing the expression of HSP 70,reducing inflammatory cytokine release and peroxide biosynthesis in LPS shock.These results suggest that glutamine have potential beneficial therapeutic effect for septic shock patients.     

Renoprotective effects of sesamin on renal hypertensive and hyperlipidemic rats

AIM: To investigate the effects of sesamin on progression of renal injury in renal hypertensive and hyperlipidemic rats (RHHR). METHODS: RHHR was induced by 2K1C and high lipid baitvessel. After 7 weeks of intragastric administration with sesamin, the contents of serum creatinine (Scr), blood urea nitrogen (BUN), 24 h urinary protein excretion (UPE) were measured. In addition, the activity of total antioxidative capacity (T-AOC), superoxide dismutase (SOD), the concentrations of malondialdehyde (MDA), hydrogen peroxide (H2O2), and the nitric oxide synthase (NOS) and nitric oxide (NO) levels in renal homogenate were measured. RESULTS: Compared with the model group, seasamin (in 100 mg·kg-1 and 33 mg·kg-1 groups) evidently decreased the contents of Scr, BUN, UP and the concentration of MDA, iNOS, H2O2 in renal tissure. It also improved the levels of NO, cNOS and activity of SOD, T-AOC in renal tissure. CONCLUSION: Sesamin ameliorates hypertensive and hyperlipidemic-induced renal injury, probably by enhancing antioxidative activity, scavenging hydroxyl radical and restraining iNOS level.     

Changes of hydrogen sulfide content in plasma and tissues of rats with LPS-induced shock

AIM: To investigate the changes and significance of hydrogen sulfide (H2S) in both plasma and various tissues, including liver, kidney, heart, lung and arteriae aorta, in rats with LPS-induced shock. METHODS: A rat model of shock induced by injection of lipopolysaccharide (LPS) was developed. Male Wistar rats were divided into four groups: control group, LPS group, LPS+NaHS (H2S donor) group and LPS+ propargylglycine (PPG, metabolic enzyme inhibitor of H2S) group. The mean arterial pressure (MAP) of rats within 240 min was observed，and H2S contents were determined. The structures of various tissues were observed. RESULTS: Administration of LPS to male Wistar rats caused a sustained fall in MAP, various tissue injuries and a significant increase in H2S contents in plasma as well as liver, kidney, heart, lung and arteriae aorta within 240 min（all P<0.05）. Treatment with metabolic enzyme inhibitor of H2S, propargylglycine, was shown to reduce H2S content elevation in plasma as well as liver, kidney, heart, lung, and arteriae aorta, and ameliorate the hypotension and tissue injuries caused by LPS（all P<0.05）. However, treatment with H2S donor-NaHS was shown to increase H2S content elevation in plasma as well as liver, kidney, heart, lung and arteriae aorta, and aggravate the hypotension and tissue injuries caused by LPS（all P<0.05）. Endogenous H2S contents in both plasma and various tissues were negatively correlated with MAP（all P<0.05）.CONCLUSION: H2S may be a new endogenous mediator and play a role in the pathogenesis of endotoxic shock.     

Relationship between levels of plasma endothelin-1/serum nitric oxide and hearing impairment in type 2 diabetes

AIM: To evaluate the relationship between endothelin-1 (ET-1)/nitric oxide (NO) and hearing impairment in type 2 diabetes mellitus (DM).METHODS: Eighty-eight type 2 diabetic patients with no signs of microangiopathy (retinopathy and nephropathy) or peripheral neuropathy, and 53 healthy subjects in the same period were enrolled in this study. Auditory function was evaluated using pure tone audiometry. Totally,type 2 DM group (n=88) and normal control group (NC, n=53) were divided into subgroups based on the presence and absence of hearing impairment. The concentration of plasma ET-1 was detected by radioimmunoassay. The concentration of serum NO was measured by the method of nitric acid reductase.RESULTS: Significantly increased plasma ET-1 and decreased serum NO were observed in diabetic patients with hearing impairment compared with those in diabetic patients without hearing impairment. The results of multivariate logistic regression analysis showed that hearing impairment in type 2 DM group was significantly associated with elevated level of HbA1c (OR＝4.525, P<0.05), LDL-C (OR=2.381,P<0.05) and plasma ET-1 (OR＝6.207,P<0.01). Besides, elevated serum level of NO (OR＝0.862, P<0.05) was associated with lower risk of hearing impairment in diabetics.CONCLUSION: Hearing impairment may happen earlier than other complications in diabetic patients. In addition to hyperglycemia and hyperlipemia, high level of ET-1 and low levels of NO might contribute to hearing impairment in diabetic patients.     

Relationship between endothelial dysfunction and renin-angiotensin-aldosterone system under the condition of fatigue stress and effect of herbs to dredge collaterals

AIM: To investigate the mechanisms and relationship among endothelial dysfunction, renin-angiotensin-aldosterone system (RAAS) and family of interleukins under the condition of excessive fatigue, by using the rats with fatigue stress. METHODS: Healthy male Wistar rats were randomly divided into control group, homocysteine (HCY) group, fatigue stress group, renshen group, shuangshen group and tongxinluo group. Radioimmunoassay was carried out to detect plasma renin activity (PRA), angiotensin II (AngⅡ), aldosterone (ALD), endothelin (ET), thromboxane-2 (TXA2), prostaglandin I2 (PGI2) in plasma and interleukin-1β, 2, 6, 10 (IL -1β, IL -2, IL -6) in sera. ELISA was used to detect NE and IL -10. The content of nitric oxide (NO) in sera was also detected. The bioinformatical analysis was used to determine the relationship between RAAS and endothelial dysfunction. RESULTS: Compared with control group, the levels of ET-1 and TXA2 in fatigue stress group were significantly increased (P<0.01, P<0.05), but the content of PGI2 and NO was significantly decreased (P<0.01, P<0.01). Compared with control group, the renin activity in plasma of animals in fatigue stress group was significantly decreased (P<0.01), the AngⅡ, IL -1β, IL -6 level was significantly increased compared with the control group (P<0.01, P<0.01), and was significantly increased compared with the HCY group (P<0.05, P<0.01, P<0.01). The NE level showed the tendency of decrease in different degree. After the intervention of three kinds of herbs to dredge collaterals, the ET-1, AngⅡ, IL -1β, IL-6 level in plasma was decreased in different degree (P<0.05, P<0.01, P<0.01), and at the same time, the contents of NO and NE level were significantly increased (P<0.05). The ALD level in tongxinluo groups was apparently higher than that in control group and the fatigue stress group (P<0.05). The bioinformatics analysis showed that Ang II and ET, IL-1; PGI2 and ALD; NO and ALD composed of three subsystems and interrelated according to the principle of optimality of complex system, and gradual change regulation was also observed in fatigue stress group. However, in control group, HCY group and tongxinluo group, the same interrelation among subsystems was not existed. CONCLUSION: In a state of long-term excessive fatigue, vascular endothelial dysfunction may be induced, and is related with renin-angiotensin-aldosterone system imbalance and serious turbulence of the autonomic dysfunction. Herbs to dredge collaterals could improve it significantly. The results suggest that bearing excessive fatigue and pressure in long-term may be the potential risk factors to induce vascular endothelial dysfunction and further result in cardio-cerebro vascular diseases, Tongluo therapy may be one of the useful ways to prevent such diseases.     

Protective effect of catalpol on diabetic rat aorta and its antioxidant mechanisms

AIM：To investigate the protective effect of catalpol on Goto-kakizaki (GK) rat aorta and to explore its antioxidant mechanisms. METHODS：Six-month-old GK rats (n=45) were randomly divided into diabetic model group, metformin (100 mg·kg-1·d-1) group, and high-dose (100 mg·kg-1·d-1), medium-dose (50 mg·kg-1·d-1) and low-dose (10 mg·kg-1·d-1) catalpol groups. The healthy male Wistar rats (n=10) were used as control group. The rats in control and model groups were given a same volume of saline. All reagents were administered by oral gavage for 12 weeks. Blood glucose and lipids were detected by an automatic biochemical analyzer. Serum reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD) and total antioxidant capacity (T-AOC) levels were detected by commercial kits. The expression of nuclear factor E2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) in the thoracic aorta was determined by Western blotting. The pathological changes of the thoracic aorta were observed by HE staining. The ultrastructural changes of the thoracic aorta were observed under electron microscope. RESULTS：After catalpol treatment, the levels of blood glucose and blood lipids were decreased significantly, and serum levels of ROS and MDA were significantly decreased, but the activity of SOD and T-AOC were significantly enhanced. The protein expression of Nrf2 and HO-1 in the thoracic aorta were significantly increased, the thoracic aortic lesions indicated by HE staining significantly reduced, and the thoracic aortic damage under ultrastructural observation was attenuated slightly. CONCLUSION：Catalpol effectively protects GK rat thoracic aorta, which may be associated with decreasing blood lipids, reducing oxidative stress and activating Nrf2/ARE/HO-1 signaling pathways