Effect of amiodarone and metoprolol on platelet activation,fibrinolytic activity and vasoactive mediators in acute myocardial infarction in rabbits

AIM:To explore the significance of platelet activation, fibrinolytic activity and the changes of vasoactive mediators in acute myocardial infarction in rabbits and the intervention of amiodarone and metoprolol.METHODS:Fifty New Zealand white rabbits were randomly assigned to five groups, ten for each. Group Ⅰ: sham group, group Ⅱ: acute myocardial infarction(AMI) group, group Ⅲ: AMI and lidocaine group, group Ⅳ: AMI and amiodarone group, group Ⅴ: AMI and metoprolol group.The middle point of left ventricular coronary artery was ligated (groupⅡ,Ⅲ, Ⅳ and Ⅴ ) or a sham ligation(group Ⅰ). Four hours later, blood was collected for measuring plasma concentration of TXB₂, 6-Keto-PGF_1α, ET, NO, plasma activity of t-Pa and PAI.After that, the heart was taken out to evaluate the infarction size(IS).RESULTS:Plasma concentration of TXB₂, ET, NO and plasma activity of PAI were significantly higher in groupⅡ,Ⅲ, Ⅳ and Ⅴ than those in group Ⅰ(P＜0.01), but the plasma concentration of 6-Keto-PGF_1α and plasma activity of t-Pa were remarkably lower in groupⅡ,Ⅲ, Ⅳ and Ⅴ than those in group Ⅰ(P＜0.01). There were no difference in plasma concentration of TXB₂, 6-Keto-PGF_1α, t-Pa activity and infarction size in group Ⅱ,Ⅲ and Ⅳ(P＞0.05).Compared to group Ⅱ, plasma concentration of ET, NO and PAI activity were significantly decresed (P＜0.01)in group Ⅳ. Plasma concentration of TXB₂, ET, NO and plasma activity of PAI were significantly lower in groupⅤ than those in group Ⅱ(P＜0.01). Conversely, plasma concentration of 6-Keto-PGF1 and plasma activity of t-Pa were remarkably higher in group Ⅴ than those in group Ⅱ(P＜0.01). The infarction size was remarkly decrease(P＜0.01)in group Ⅴ.CONCLUSIONS:Amiodarone inhibited PAI avtivity, decreased release of ET and NO in AMI in rabbits. Metoprolol inhibited platelet activation, improved fibrinolytic, decreased release of ET and NO, and reduced myocardial infarction size in AMI in rabbits; Lidocaine had no effect above.     

Effects of irbesartan and perindopril on the myocardial expression of connexin 43, desmin and cardiac troponin T in rat cardiac hypertrophy induced by pressure overload

AIM: To investigate the effects of angiotensinⅡ receptor type Ⅰ antagonist irbesartan and angiotensin-converting enzyme inhibitor perindopril on the myocardial expression of connexin 43 (CX43), desmin and cardiac troponin T (cTnT) in the pressure overload-induced rat cardiac hypertrophy. METHODS: 40 male adult Sprague-Dawley rats were divided into 5 groups (8 animals for each): sham operation group and other four groups with ventricular hypertrophy caused by banding aortic artery. Drugs were given one week after operation as follows: sham operation group, normal saline (2 mL·kg-1·d-1 ig) was given; Operative groups: animals with ventricular hypertrophy were treated with normal saline 2 mL·kg-1·d-1 ig; Treatment groups: animals with ventricular hypertrophy were treated with perindopril 2 mg·kg-1·d-1 ig, irbesartan 20 mg·kg-1·d-1 ig or irbesartan 20 mg·kg-1·d-1 ig plus perindopril 2 mg·kg-1·d-1 ig, respectively. Left ventricular mass index (LVMI), transverse diameter of myocardial cell (TDM), and myocardial expression of CX43, desmin and cTnT by immunohistochemistry were performed at the end of 8 weeks of drug intervention. RESULTS: LVMI, TDM were remarkably decreased after drug intervention, compared to animals of operative group (P<0.05). Left ventricular hypertrophy induced by aortic banding in rats were associated with marked disorganization of gap junction distribution. In hypertrophied myocytes, CX43 immunolabeling was dispersed over the entire cell surface rather than confined to the intercalated disks. The CX43 were mainly distributed in the intercalated disks in irbesartan group, perindopril group and their combined group. The myocardial expression of CX43, desmin and cTnT in the operative group was lower than that in irbesartan group, perindopril group and their combined group (P<0.05). CONCLUSION: These data indicate that irbesartan and perindopril play beneficial roles in the myocardial CX43, desmin and cTnT expression and their distribution, and the restoration of myocardial cell structure and gap junction in pressure-overload myocardium hypertrophy.     

Downregulation of aortic angiotensin II type 1 receptor mRNA expression by simvastatin in hyperlipidemic rats

AIM:To study the impact of hyperlipidemia on aortic AT₁ mRNA expression and vasoactive substances, and investigate the potential mechanism on reversion of endothelial dysfunction during the statin therapy.METHODS:The investigation included control, hyperlipidemic and simvastatin-treated groups. Hyperlipidemic model was set up on the 4-week atherogenic diet, followed by a 16-week treatment in the simvastatin treated group (simvastatin 10 mg·kg^-1·d^-1) and without treatment in the hyperlipidemic group. Serum lipid level, the expression of AT₁mRNA of aorta and level of serum AngⅡ and nitric oxide (NO) were measured. RESULTS: Compared with the control group, hyperlipidemic rats showed a stronger expression of AT₁ mRNA and lower level of NO. No significant difference in systolic blood pressure and AngⅡ was showed in this group. In contrast, in simvastatin treated group, expression of AT₁ mRNA as well as lipid(TC, TG, LDL-C) levels were significantly decreased and NO level increased which associated with improvement of endothelial dysfunction. CONCLUSION:By regulated the lipid level, downregulated AT₁ mRNA expresstion and increased the NO activity, simvastatin restored endothelial function and inhibited atherogenesis.     

Angiotensin Ⅱ stimulates the expression of NADPH oxidase subunit p47phox mRNA in kidney in a rat model of hyperoxaluria

AIM: To investigate the roles of angiotensin Ⅱ and NADPH oxidase in the development of renal oxidative stress (OS) in a rat model of hyperoxaluria. METHODS: Animal model of hyperoxaluria was established in adult male Sprague-Dawley rats by administration of 0.8% ethylene glycol (EG) in drinking water for 4 weeks. Simultaneous treatment with apocynin (0.2 g·kg-1·d-1) or losartan (30 mg·kg-1·d-1) by intragastric administration were performed in rats, respectively. At the end of the study, markers for the state of oxidative stress (OS), urinary 8-IP and the enzymatic activity of superoxide dismutase (SOD) in kidney homogenates were assessed. The concentration of angiotensin Ⅱ in kidney homogenates was determined using radioimmunoassay method. Expression of NADPH oxidase subunit p47phox in kidney was localized and evaluated by immunohistochemistry and real time-PCR, respectively.RESULTS: p47phox expressed widely in the kidneys of this rat model, including renal cortex, inner medulla and outer medulla. Compared with the control, OS developed significantly in rats received EG, with increased expression of p47phox mRNA in kidneys. Renal angiotensin II also increased significantly. Treatment with apocynin or losartan significantly reduced the excretion of urinary 8-IP, restored the SOD activity, with decrease in the expression of p47phox mRNA in kidney, but the levels of those OS markers in apocynin or losartan treated rats were still higher than those in normal controls. CONCLUSION: Results suggest that renal Ang II and its stimulation of NADPH oxidase may partially account for the development of OS in kidney in this rat model of hyperoxaluria.     

Prevention and treatment of restenosis after PTA operation in rabbit artery by 3,3-diindolylmethane

AIM: To evaluate the safety and efficacy of 3,3-diindolylmethane (DIM) on neointimal proliferation of rabbit artery after balloon angioplasty. METHODS: Restenosis models of carotid artery after balloon injury was established in rabbits. 30 rabbits were randomly divided into 4 groups: sham-operated group, model group, low-dose DIM group and high-dose DIM group. DIM was given to the rabbits in low-dose treatment group (2 mg·kg-1·d-1) and high-dose treatment group (8 mg·kg-1·d-1) once a day from 3 d before operation to 4 weeks after operation. The two treatment groups were administered with intraperitoneal injection of emulsified DIM, while the other two groups with saline at the same volume. All rabbits were killed after 28 d and carotid arteries were removed. With HE staining, automatic image analysis and immunohistochemistry, artery morphology was observed and the thickness of arterial intima and media was measured. Platelet derived growth factor (PDGF) and transfer growth factor β1 (TGF-β1) were examined. The expression of 〖STBX〗bcl-2〖STBZ〗 gene was detected by in situ hybridization (ISH) with computer-assisted picture analysis system. RESULTS: No significant difference was found between low-dose DIM group and model group in intimal thickness, media thickness, luminal area and the expression of PDGF and TGF-β1 in low-dose DIM group (P>0.05). The intimal thickness was decreased in high-dose DIM group compared with model group and low-dose DIM group (P<0.01). The luminal area was significantly larger in high-dose DIM group than that in model group and low-dose DIM group (P<0.01). The expression of PDGF and TGF-β1 in low-dose DIM group was significantly reduced compared with model group and low-dose DIM group (P<0.01). CONCLUSION: The inhibition and treatment of DIM on arterial restenosis are safe and effective. The effect might be achieved by preventing neointimal proliferation and the expression of PDGF and TGF, enhancing apoptosis in the vascular smooth muscle cells.     

Effects of TNF-α-mediated insulin resistance on INSIG2 and SCAP expressions in vivo

AIM: To investigate the effects of TNF-α induced insulin resistance (IR) on INSIG1, INSIG2, SCAP and SREBP expressions in mice. METHODS: Male C57BL/6J mice were randomly divided into 4 groups. The mice were given an intraperitoneal injection of TNF-α (6 μg·kg-1·d-1; 3 μg·kg-1·d-1 and 1 μg·kg-1·d-1) and saline (NC group) twice daily for 7 d. The insulin sensitivity and glucose metabolism in awaken mice were evaluated by intravenous glucose tolerance test (IVGTT). The mRNA expression and protein levels of gene were measured by RT-PCR and Western blotting. RESULTS: After TNF-α treatment, fasting blood glucose (FBG), plasma insulin and free fatty acids (FFA) were significantly elevated in TNF-α (6 μg·kg-1·d-1) group compared to NC, TNF-α (1 μg·kg-1·d-1) and TNF-α (3 μg·kg-1·d-1) groups (P<0.01 and P<0.05, respectively). There was a lower glucose tolerance in TNF-α (6 μg·kg-1·d-1) group than that in other three groups during IVGTT. In TNF-α (6 μg·kg-1·d-1) group, the insulin release of glucose-stimulation was higher than that in NC and TNF-α (1 μg·kg-1·d-1) groups (P<0.01 and P<0.05). The INSIG2 mRNA expression of adipose tissues in TNF-α (6 μg·kg-1·d-1) group was significantly increased compared with NC group (P<0.01), and INSIG2 protein levels were also increased (P<0.05). In TNF-α treatment mice, SCAP mRNA level in adipose tissues was significantly up-regulated than that in the controls (P<0.05). The mRNA expressions of INSIG1 and SREBP1 in two groups were not significantly changed (P>0.05). CONCLUSION: In TNF-α induced insulin resistance, INSIG2 and SCAP may be involved in the pathways of lipid metabolism.     

The renoprotective role of all-trans retinoic acid in retarding rat glomerulosclerosis with 5/6 nephrectomy

AIM: To explore if all trans retinoic acid (atRA) retards glomerulosclerosis of rats with 5/6 nephrectomy. METHODS: Wistar male rats were operated by subtotal nephrectomy and were randomly divided into A1 (5 mg·kg-1·d-1 atRA), A2 (10 mg·kg-1·d-1 atRA), A3 (20 mg·kg-1·d-1 atRA) and NX (vehicle) groups. Each group included 8 rats. 8 health rats were assigned as sham-operation group (sham group). Animals were sacrificed 10 weeks after treatment. The concentrations of plasma atRA were measured by reversed phase high performance liquid chromatography (RP-HPLC). Glomerulosclerosis was evaluated by glomerulosclerosis index system. The expression of transforming growth factor-beta 1 (TGFβ1) was measured by renal immunohistochemical staining and Western blotting. RESULTS: The concentrations of atRA in atRA groups were much higher than that in NX and sham groups. Compared to NX, the remnant kidney sclerosis was ameliorated significantly in A1, A2 and A3 groups. The expressions of TGFβ1 decreased parallelized to the levels of glomerulosclerosis. CONCLUSION: atRA has a beneficial effect on retarding the progression of renal fibrosis in the 5/6 nephrectomic rats, possibly through downregulating the glomerular TGFβ1 expression.     

Effect of micronised fenofibrate on lipotoxicity and insulin sensitivity in spontaneously hypertensive rats treated with high-fat diet

AIM: To observe the effect of micronised fenofibrate (lipanthyl) on lipotoxicity and insulin sensitivity (IS) in spontaneously hypertensive rats (SHR) with high-fat diet.METHODS: Twenty-seven SHR were randomly divided into three groups: normal chow group (n=9), high-fat diet group (n=9) and micronised fenofibrate treatment group (n=9). Micronised fenofibrate 100 mg·kg-1·d-1 was given orally to SHR, which diet on high-fat diet for three months. Intramuscular lipids were observed and lipids accumulation index (LAI) was calculated. Nonesterified fatty acid, glucose and insulin were determined in all rats.RESULTS: (1) Compared to SHR in normal chow diet group, body weight and the level of serum TG and TC increased significantly and the level of HDL-C decreased significantly in SHR fed with high-fat diet (P<0.05). Micronised fenofibrate significantly decreased systolic blood pressure, body weight, the level of serum TG and TC, increased the level HDL-C (P<0.05). (2) Fasted blood glucose, free fatty acid (FFA), GLU-AUC obviously increased in high-fat diet group compared with normal chow diet group. Insulin sensitivity index (ISI) in high-fat diet group was much lower than that in normal chow diet group (0.0038±0.0007 vs 0.0053±0.0013, P<0.05). No difference was found between fenofibrate-treated group and normal chow diet group. (3) There were more lipid drops in intramuscular cells of SHR treated with high-fat diet than those in fenofibrate-treated group and normal chow diet group (LAI: 6.42±0.59 vs 3.32±0.77 and 1.98±0.97, P<0.05). After covariance analysis, the results above-mentioned also made sense (F=10.46, P<0.05). (4) Inverse association was found between LAI and ISI (r=-0.58, P<0.05). Positive correlations were found between LAI and TG, FFA, body weight.CONCLUSION: In addition to regulating lipid, micronised fenofibrate may reduce BP, body weight, FFA, lipid accumulation in intramuscular cells and improve insulin sensitivity of SHR treated with high-fat diet.     

Preventive function of citalopram on neuro-cell apoptosis caused by long-term stress in CA1 and CA3 region of hippocampus

AIM: To explore the preventing effect of citalopram on neuro-cell apoptosis caused by long-term stress in CA1 and CA3 region of hippocampus. METHODS: Forty male Sprague Dawley (SD) rats were randomly divided into five groups including blank group, control group (the control group was filled the stomade by 0.9% saline) and three experimental groups (intragastric administration of citalopram hydrobromide at doses of 8 mg·kg-1·d-1, 4 mg·kg-1·d-1, 1 mg·kg-1·d-1, respectively). Rat stress model was made by compulsory swimming everyday for 4 weeks. Cell apoptosis in CA1 and CA3 region of hippocampus was observed by HE staining method. Apoptotic cell numbers and integral optical density in CA1 and CA3 region were tested and analyzed by terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) method and Norton Internet Security BR (NIS BR) software. t-test was applied to compare apoptosis cell numbers and integral optical density. RESULTS: Control rats showed more static time and less struggling times. Conversely, static time was shorter and rats spent more time after exhaustive exercise, and more struggling times in the experimental group. Rats in control group showed more positive cells in CA1 and CA3 regions and higher integral optical density in CA3 region than those in blank group. Rats in experimental groups showed fewer positive cells in CA1 and CA3 regions. Rats in experimental group 1 and group 3 showed higher integral optical density in CA1 and CA3 regions than that in control group. CONCLUSION: Long-term stress might cause neuro-cell apoptosis in CA1 and CA3 region of hippocampus. Citalopram might have prophylactic effect on apoptosis caused by long-term stress in CA1 and CA3 region, and the prophylactic effect might not be influenced by citalopram. Our study suggests that the treatment mechanism of citalopram in neural and mental illness by long-term stress may involve in a major role by antagonizing neuronal apoptosis in both the CA1 and CA3.     

Effects of testosterone on endothelial function and intimal proliferation after balloon injury in male rabbit abdominal aorta

AIM: To investigate the effects of testosterone on endothelial function and intimal proliferation after balloon injury in male rabbit abdominal aorta. METHODS: 24 male New Zealand white rabbits were divided randomly into three groups: control group (n=8, sham castration), hypotestosteronemia group (n=8,castration) and testosterone replacement group (n=8,castration +testosterone undecanoate intramuscular injection,14mg/kg). Abdominal aorta was injured with 3 mm PTCA balloon after testosterone undecanoate had been injected for three days. Two weeks later, blood samples were obtained for detection of plasma testosterone, lipids, metabolic product of nitric oxide (NO₂^-／NO₃^-), superoxide dismutase(SOD) and malondialdehyde (MDA),and all the abdominal aorta were excised to be analyzed by computer. RESULTS: The intimal area of hypotestosteronemia group were significantly larger than that of other two groups(P＜0.01). plasma NO₂^-／NO₃^- and SOD levels were significantly decreased, while the total cholesterol(TC),triglycerides(TG), low density lipoprotein(LDL) and plasma MDA were significantly increased. No difference was observed between control group and testosterone replacement group in all parameters. CONCLUSION: Testosterone, at physiological level,had the effects of inhibiting the intimal proliferation and of protecting the endothelial function after balloon injury in male rabbit abdominal aorta.     

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.     

High-cholesterol diet with or without corn oil for establishing atherosclerotic model in rabbits

AIM：To compare the reliability and plaque area between using high-cholesterol diet and high-cholesterol diet with corn oil to establish a rabbit atherosclerotic model. METHODS：Eighteen New Zealand rabbits were randomly divided into 3 groups (6 rabbits each): normal diet group (group C), high-cholesterol diet group (group H1) and high-cholesterol diet containing 6% corn oil group (group H2). All rabbits were fed for 12 weeks, and their body mea-sured was weighed at the end of every weeks. The serum levels of high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC) and triglyceride (TG) were measured by automatic chemistry analyzer at 0 week and 12 weeks. At the end of 12 weeks, the thoracic aorta of 8-cm length since aortic root was isolated from the rabbit after anesthesia, and stained with Sudan IV or oil red O to verify the existence of plaque. The percentage of plaque area (PA/IA) in the intima area was further calculated by ImageJ2x software. RESULTS：At the end of 12-week feeding, the serum levels of HDL-C, LDL-C and TC in both group H1 and group H2 were significantly higher than those in group C, and serum TG in group H2 was significantly higher than that in group C. Serum HDL-C in group H2 was significantly higher than that in group H1, but no significant difference of serum LDL-C, TC and TG between group H1 and group H2 was found. There was no plaque in the intima in group C, and plaques were observed in the intima of all rabbits in group H1 and group H2. Rabbit atherosclerotic models in both group H1 and group H2 were established with a success rate of 100%. The values of PA/IA in group H1 ［(49.74±18.78)%］ and group H2 ［(56.95±26.74)%］ were both significantly higher than that in group C (0%), and no significant difference of PA/IA between group H1 and group H2 was observed. CONCLUSION：High-cholesterol diet with or without corn oil can establish a rabbit atherosclerotic model with a success rate of 100% after 12-week feeding, and the percentage of plaque area in the total aortic intimal area is not different in the 2 feeding methods.     

Effect of tanshinone ⅡA on liver lipid deposition and ferroptosis-related protein expression in ApoE-/- mice

AIM To observe the effect of tanshinone ⅡA on liver lipid deposition and ferroptosis-related protein expression in ApoE^-/- mice. METHODS Thirty-two ApoE^-/- mice were randomly divided into model group, high-dose (60 mg/kg) tanshinone ⅡA group, low-dose (30 mg/kg) tanshinone ⅡA group and simvastatin group, and C57BL/6J mice (n=8) were used as normal control group. The mice in normal control group were given the basic feeding, while the others were given high-fat diet. The mice in tanshinone ⅡA groups and simvastatin group were given corresponding drugs. The mice in normal control group and model group were intraperitoneally injected with equal volume of saline. Eight weeks later, the serum levels of triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were tested by automatic biochemistry analyzer. The liver tissues were stained with HE and oil red O. The contents of reactive oxygen species (ROS) and glutathione (GSH) in liver tissues of the mice were measured by commercially available kits. The liver glutathione peroxidase 4 (GPX4) and p53 were detected by immunohistochemical method. The protein and mRNA expression levels of ferroptosis-related factors GPX4, xCT/SLC7A11, p53 and ferritin heavy chain 1 (FTH1) were determined by Wes automatic Western blot quantitative analysis system and RT-qPCR. RESULTS Compared with normal control group, the serum levels of TC, TG and LDL-C in model group were increased significantly (P<0.05 or P<0.01), and HDL-C did not change significantly. The fat vacuoles were clearly visible in liver tissue. The content of ROS in liver tissue was increased significantly,and GSH was decreased significantly (P<0.01). The mRNA and protein expression levels of p53 were increased significantly, and GPX4, xCT/SLC7A11 and FTH1 were decreased significantly (P<0.05 or P<0.01). Compared with model group, tanshinone ⅡA significantly decreased the serum levels of TC, TG and LDL-C (P<0.05 or P<0.01), and HDL-C did not change significantly. High-dose and low-dose tanshinoneⅡA also significantly decreased the degree of steatosis, and the size of lipid droplets. The content of ROS in liver tissues was decreased significantly, and GSH was increased significantly (P<0.01). The mRNA and protein expression levels of GPX4, xCT/SLC7A11 and FTH1 were increased significantly, and p53 were decreased significantly (P<0.05 or P<0.01). CONCLUSION Tanshinone ⅡA reduces liver lipid deposition and lipid peroxidation damage in ApoE^-/- mice, which may be related to the intervention of ferroptosis-related proteins in the liver cells.     

Angiotensin 1-7 attenuates angiotensin Ⅱ-induced human glomerular endothelial cell injury via Mas receptor

AIM:To investigate the effect of angiotensin 1-7 (Ang1-7) on the human glomerular endothelial cells (HGECs) injury induced by angiotensin Ⅱ (Ang Ⅱ) and its possible mechanism. METHODS:Cultured HGECs were divided into 6 groups randomly:control group, Ang Ⅱ group, Ang1-7 group, Ang Ⅱ +Ang1-7 group, Ang Ⅱ +Ang1-7+A779 (an inhibitor of Mas receptor) group and A779 group. The apoptotic rate and reactive oxygen species (ROS) of HGECs were analyzed by flow cytometry and photographed by fluorescence microscopy. The levels of lactate dehydrogenase (LDH), nitric oxide (NO), endothelin-1 (ET-1), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), transforming growth factor-β (TGF-β), monocyte chemoattractant protein-1 (MCP-1) and intercellular adhesion molecule-1 (ICAM-1) in the supernatant of cell cultures were measured. RESULTS:Compared with the control group, the apoptotic rate and the average fluorescence intensity of ROS were increased in the Ang Ⅱ group, IL-6, TNF-α, TGF-β, ICAM-1 and MCP-1 in cell supernatants were also increased in the Ang Ⅱ group (P<0.05). Compared with the Ang Ⅱ group, the apoptotic rate, ROS level, and the above inflammatory factors were decreased in Ang Ⅱ +Ang1-7 group (P<0.05). Compared with the Ang Ⅱ +Ang1-7 group, adding A779 increased the cell apoptotic rate, ROS production and the releases of the above inflammatory factors in cell supernatants (P<0.05). Compared with the Ang Ⅱ group, adding Ang1-7 inhibited the LDH leakage, ET-1 secretion and promoted the release of NO in a dose-dependent manner (P<0.05). CONCLUSION:Ang1-7 attenuates the HGECs injury induced by Ang Ⅱ by inhibiting the Mas receptor.     

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

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

Clinical studies of L-Arg effect on essential hypertension

AIM and METHODS:To investigate the effect of L-arginine -nitric oxide pathway on patients with essential hypertension via hemodynamics and neuroendocrinology. 24 essential hypertension patients were randomly divided into two groups, group I was given L-Arg, and groups Ⅱ was given normal saline as control. Blood pressure, heart rate, heart funtion, nitric oxide, angiotensinⅡ, endothelin, thromboxane A₂ and prostacyline were measure in all patients. RESULTS: In group Ⅰ arterial pressure decreased, heart rate increased, cardial output, systolic volume and eject fraction increased, total peripheral resistance decreased. NO and PGI₂ levels were inceased. But at 80 min , with NO concentration decreased, SBP,DBP were increased, TPR, FT and AngⅡ were also increased. While HR, CO, SV and EF were decreased. However TXA₂ and PGI₂ showed not much change. CONCLUSION: Exogenous L-arginine produced a vasodilatory effect by increasing NO production ,caused the change of other hemodynamic function . It also indirectly changed plasma ET, AngⅡlevels by negative feed-back and suppressed the accumulation of platelet.     

Angiotensin Ⅱ stimulates TNF-α and NO production in peripheral blood mononuclear cells in heart failure patients

AIM: To examine the change of serum tumor necrosis factor-α (TNF-α), nitric oxide (NO) in patient with congestive heart failure (CHF) and the effect of angiotensin Ⅱ (AngⅡ), valsartan on TNF-α and NO production in culture peripheral blood mononuclear cells (PBMC), to assess the relationship between the renin-angiotensin system and cytokines. METHODS: Venous blood of both healthy volunteers (n=12) and patients with CHF (n=16) were collected. Serum TNF-α and NO were examined. Peripheral blood mononuclear cells (PBMC) were obtained from both the control and the patients groups and cultured with AngⅡ at concentrations of 0, 0.01, 0.1, 1 μmol/L, respectively. AngⅡ at concentration of 0.1 μmol/L combined with 0.1 μmol/L of valsartan was also used. After 24 h incubation, the contents of TNF-α and NO in the culture supernatants were measured. RESULTS: Serum TNF-α and NO production in CHF group were significantly higher than that in control group (P<0.01). The higher the heart failure degree, the higher the levels of TNF-α and NO (P<0.01), and no significant among different etiologies of CHF (P＞0.05) were observed. AngⅡ stimulated TNF-α and NO release from PBMC of patients with CHF and normal person, which was inhibited by valsartan. CONCLUSIONS: AngⅡ obviously increases TNF-α and NO production from PBMC, which indicates there is relationship between the renin-angiotensin system and TNF-α, NO. The fact that valsartan inhibits TNF-α production may be one of the mechanisms in treating CHF.     

Role of MMP2/TIMP1 in the vascular remodeling after angioplasty in rabbits

AIM: To discuss the effects of matric metalloproteinasez and tissue inhibitor 1 (MMP2/TIMP1) on the vascular remodeling after angioplasty and the regulatory effect of tongxinluo on it in rabbits. METHODS: 65 male white rabbits (2.5-3.5 kg; 6-8 months) were divided into 4 groups: control group (n=5, normal diet ), injury group (n=20, normal diet plus intimal injury), high-lipid group (n=20, high cholesterol diet plus intimal injury) and tongxinluo group (n=20, tongxinluo 0.5 mg·kg-1·d-1, 4 weeks, also high cholesterol diet plus intimal injury). Under X-ray the narrow parts of the vessel underwent angioplasty. All rabbits were killed and vessel samples were excised, respectively, for the detection of histomorphometry immunohistochemically and RT-PCR. The data were expressed as ±s. RESULTS: (1) The change of vascular morphological results showed that the intimal area in tongxinluo group was less than that in high-lipid group (P<0.05), inversely the lumen area in tongxinluo group was higher than that in high-lipid group (P<0.05). The difference between the increase in lumen area and the decrease in intimal area suggested that the vascular remodeling exist. (2) RT-PCR showed that the relative level of mRNA of MMP2 and TIMP1 in tongxinluo group was less than those in high-lipid group (P<0.05). (3) The immunohistochemical staining showed that the light absorption of MMP2 and TIMP1 in Tongxinluo group was less than that in high-lipid group (P<0.05). CONCLUSION: Tongxinluo inhibits the accumulation and secretion of extracellular matrix, also inhibits vascular remodeling in rabbits, which is related with MMP2 and TIMP1.     

Effects of Ang Ⅱ on the production of ET-1, NO from adult rat myocardial fibroblasts

AIM: To investigate the effects of Ang Ⅱon the production of ET-1, NO from myocardial fibroblasts (MFs) of adult rat. METHODS: MFs were extracted by enzymatic digestion and anchorage velocity-dependent separation method. In this study, the changes of ET-1 and NO production from MFs in the second passage were examined by radioimmunoassay and by nitrate reductase-dependent assay, separatively. RESULTS: In a specific concentration range, AngⅡ increased ET-1 synthesis in MFs in a concentration-dependent manner. Losartan, the antagonist of angiotensin Ⅱ 1 type recepters (AT₁R), blocked the above effects. Ang Ⅱ may inhibit NO synthesis in MFs. When MFs were treated with losartan+Ang Ⅱ, the production of NO increased significantly, and was higher than that treated with the others (P<0.01). CONCLUSION: Ang Ⅱ may increase the production of ET-1 in MFs via AT₁R and affect NO production in MFs mainly via AT₁R to change the ratio of ET-1 and NO. Ang Ⅱ maybe exert inductive effects on myocardial hypertrophy and heart failure by affecting these complicated balances between bioactive factors produced from MFs.