Effects of atorvastatin on release of endothelial microparticles and myocardial apoptosis in rats with acute myocardial infarction

AIM: To investigate the effect of atorvastatin(AT) on the release of endothelial microparticles(EMP) and myocardial apoptosis in the rats with myocardial infarction. METHODS: SD male rats(n=24) were randomly divided into 3 groups:sham operation(sham) group, myocardial infarction(MI) group and MI+AT group. The rat model of acute myocardial infarction was prepared by coronary artery ligation. At 2 h and 24 h after modeling, the peripheral blood was collected to detect creatine kinase-MB(CK-MB) and cardiac troponin T(cTnT). The circulating levels of EMP were measured by flow cytometry. The myocardial apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling(TUNEL) assay. RESULTS: At 2 h after modeling, the level of CK-MB was significantly increased in MI group compared with sham group, and the level of EMP and the myocardial apoptotic rate were significantly increased in MI group and MI+AT group compared with sham group. At 24 h after modeling, the level of EMP was significantly increased in MI group compared with sham group. The levels of CK-MB, cTnT, EMP and the myocardial apoptotic rate were significantly decreased in MI+AT group compared with MI group. Moreover, the level of CK-MB in MI group was significantly increased at 24 h compared with that at 2 h after modeling. The levels of CK-MB, cTnT and EMP were significantly decreased in MI+AT group at 24 h compared with those at 2 h after modeling. CONCLUSION: Ator-vastatin may reduce the level of EMP and the myocardial apoptotic rate in the rats with acute myocardial infarction, indicating that atorvastatin plays a role in protecting endothelium.     

Relationship between NLRP3 inflammasome-IL-1β axis and End-MT after acute myocardial infarction in rats

AIM: To investigate whether activation of NLRP3 inflammasome-IL-1β axis is consistent with endothelial-mesenchymal transition (End-MT) during the process of myocardial fibrosis after acute myocardial infarction (AMI). METHODS: Adult male SD rats (n=30) were randomly divided into sham operation group (n=15) and AMI group (n=15). After 28 d, Masson staining was used to detect the level of myocardial fibrosis. The activation of NLRP3 inflammasome including NLRP3, ASC, pro-caspase-1 and caspase-1, the endothelial cell markers CD31 and VE-cadherin, and the mesenchymal cell markers α-SMA and FSP1 were analyzed by Western blot. The expression of IL-1β was measured by ELISA. RESULTS: The levels of myocardial fibrosis and End-MT, the activation of NLRP3 inflammasome, and the expression of caspase-1 and IL-1β were significantly increased in AMI group compared with sham operation group (P<0.05). CONCLUSION: The activation of NLRP3 inflammasome-IL-1β axis is significantly consistent with End-MT process, suggesting that NLRP3 inflammasome-IL-1β, as a potential target for the activation of End-MT, will provide a novel theoretical target for the treatment of myocardial fibrosis and heart failure after AMI.     

Effect of atorvastatin on cardiac function and HGF/c-Met signaling pathway after acute myocardial infarction in diabetic rats

AIM: To investigate the effect of atorvastatin on myocardial apoptosis, ventricular remodeling and cardiac function after acute myocardial infarction (AMI) in diabetic rats, and to explore whether the effect is mediated by hepatocyte growth factor (HGF)/c-Met signaling pathway. METHODS: Diabetes in 70 male SD rats was induced by intraperitoneal injection of streptozotocin (STZ, 65 mg/kg). After 8 weeks, AMI was induced by the ligation of the left anterior descending coronary artery in the diabetic rats, and 32 surviving rats were divided into AMI group (n=16) and AMI＋atorvastatin group (n=16, 20 mg·kg-1·d-1) at random. The similar surgical procedure was completed in sham group (n=11) without coronary ligation. Atorvastatin was given daily by gavage from the first day after AMI. Two weeks later, the cardiac function, pathological changes of myocardial tissues, myocardial apoptosis, and the expression of HGF and c-Met were compared among groups. RESULTS: AMI significantly reduced cardiac function, increased collagen volume fraction (CVF) and myocardial apoptotic index, and up-regulated the expression of HGF and c-Met at mRNA and protein levels in AMI control group (P<0.05). The cardiac function was improved, and CVF and myocardial apoptotic index were reduced by the treatment with atorvastatin, which also up-regulated the expression of HGF and c-Met (P<0.05). CONCLUSION: Atorvastatin significantly attenuates myocardial apoptosis and cardiac remodeling, and improves cardiac function after AMI in diabetic rats by further enhancing the activation of HGF/c-Met pathway.     

Short-term cardioprotective effects of trimetazidine on acute myocardial infarction in rats

AIM: To observe the myocardial protective effects of trimetazidine on myocardial infarction (MI) in Sprague-Dawley (SD) rats. METHODS: Ninety SD rats were randomly assigned to 3 groups (n=30 each): myocardial infarction group (MI group), MI+trimetazidine group (MT group) and sham group (S group). By permanently ligating the left anterior descending artery, the MI model was set up in the rats in MI group and MT group. Before and after setting up the MI model, normal saline was given to the rats in MI and S group by gavage. On the other hand, trimetazidine (3 mg/kg,twice per day) was given to the rats in MT group by gavage. At 8 h, 24 h and 48 h after applying trimetazidine, the serum level of cardiac troponin I (cTnI) was measured. At the 1st week, 2nd week and 4th week after treated with trimetazidine, the size of myocardial infarction, the maximum rising rate of the left ventricular systolic pressure (+dp/dt_max) and the maximum descending rate of the left ventricular diastolic pressure (-dp/dt_max) were measured. Also at the 1st week after applying trimetazidine, the cardiomyocyte apoptotic index was detected. RESULTS: Compared with MI group 2 weeks after applying trimetazidine, +dp/dt_max significantly increased in MT group , and -dp/dt_max also significantly increased in MT group . Four weeks after applying trimetazidine, +dp/dt_max significantly increased in MT group , and -dp/dt_max also significantly increased in MT group . At 8 h and 48 h after applying trimetazidine, no statistically significant difference (P＞0.05) of serum cTnI between MI group and MT group was observed. However, at 24 h after applying trimetazidine, the serum level of cTnI decreased in MT group as compared with MI group . Aditionally, trimetazidine significantly decreased the infarction size of myocardium in MT group (0.248±0.052) as compared with MI group (0.362±0.082, P<0.01). CONCLUSION: Trimetazidine has short-term cardioprotective effects on the rats with acute MI by improving myocardial systolic and diastolic functions, reducing infarct size and inhibiting apoptosis.     

Combinational effects of trimetazidin and parecoxib on acute myocardial infarction in rats

AIM: To investigate the protective effects and mechanisms of combinational use of trimetazidine(TMZ) and parecoxib sodium on acute myocardial infarction (AMI) in rats. METHODS: Sixty-six Sprague-Dawley rats were randomly divided into 5 groups: sham group; AMI group; AMI+TMZ group; AMI+parecoxib group; AMI+TMZ+parecoxib group. All rats were sacrificed and cardiac functions (HR, LVSP, LVEDP, +dp/dt_max,-dp/dt_max) were measured with a Pclab-3804 biological signal processing system on the 8th day. The infarct size in each group was checked up by TTC staining method. RT-PCR was employed to detect the bax mRNA and bcl-2 mRNA. The protein levels of COX-2, Bax, Bcl-2 and cleaved caspase-3 in myocardium were determined by Western blotting. The activity of caspase-3 in each group was measured by colorimetric assay kit, and the apoptotic rates were detected with DNA ladder kit.RESULTS: Compared with sham group, increased expression of COX-2 protein (P<0.01) was observed in AMI group. The expression of COX-2 protein in parecoxib group was lower than that in AMI group (P<0.01). Compared with AMI group, the combinational use of trimetazidin and parecoxib improved contractile functions (LVSP and +dp/dt_max), reduced the infarct size and lowered the apoptotic rates remarkably. Specifically, the combinational use of trimetazidin and parecoxib showed better effects than use of trimetazidin or parecoxib alone. Reduced expression of Bax/Bcl-2 mRNA and protein, the reduced caspase-3 activity and cleaved caspase-3 expression were also found in combinational group as compared with other groups (P<0.05).CONCLUSION: The combinational use of trimetazidin and parecoxib effectively improves cardiac functions and reduces infarct size. The mechanism of the protective effect is probably associated with inhibiting apoptosis of cardiac myocytes.     

Cardiac protective effect of granulocyte colony-stimulating factor combined with ischemic postconditioning on acute myocardial infarction in rabbits

AIM: To investigate the protective effect of granulocyte colony-stimulating factor (G-CSF) combined with ischemic postconditioning (IP) on acute myocardial infarction (AMI). METHODS: Male New Zealand rabbits were randomly divided into 4 groups (n=15) after 30 min of left ventricular artery (LVA) occlusion: the rabbits in ischemia-reperfusion (IR) group were directly given reperfusion|the rabbits in G-CSF group were subsequently treated with G-CSF (10 μg·kg^-1·d^-1) by subcutaneous injection after direct reperfusion|the rabbits in IP group received 4 episodes of 30 s reperfusion and 30 s occlusion before total reperfusion|the rabbits in IP combined with G-CSF (IP+G-CSF) group were treated with both IP and G-CSF. Electrocardiogram (ECG) monitoring was performed during the operation. Blood was drawn to evaluate white blood cell count (WBC) and cardiac troponin I (cTnI) before operation and 7 d later. Ultrasound cardiography was performed to evaluate left ventricular remodeling and functions 4 weeks after operation. The sizes of infarcted myocardium were determined by triphenyltetrazolium chloride (TTC) staining. Apoptosis of cardiomyocytes was measured by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL) staining. RESULTS: ST-segment resolutions were significantly decreased in IP group and IP+G-CSF group compared with direct reperfusion groups (P<0.05). WBC significantly increased in the groups treated with G-CSF for 1 week. The values of cTnI after operation were significantly lowered in G-CSF group, IP group and IP+G-CSF group as compared with IR group (P<0.05). Left ventricular ejection fraction, the size of infarcted myocardium and apoptosis of cardiomyocytes were better in IP group, G-CSF group and IP+G-CSF group than those in IR group. CONCLUSION: G-CSF combined with IP is a promising strategy against cardiac reperfusion injury and accelerates cardiac repair in AMI.     

Effects of stachydrine hydrochloride on experimental acute cerebral infarction in rats

AIM: To observe the therapeutic effect of stachydrine hydrochloride on experimental acute cerebral infarction in rats and to explore the underlying mechanisms. METHODS: SD rats (n=75) were randomly divided into 5 groups: sham group, cerebral infarction model group, and stachydrine hydrochloride (10 mg/kg, 20 mg/kg and 40 mg/kg) treatment groups. After the establishment of cerebral infarction model, the rats were given stachydrine hydrochloride at dose of 10 mg/kg, 20 mg/kg or 40 mg/kg by gavage daily for 14 d. The impairment of neurological function in each group was scored. The cerebral infarction volume and brain water content were measured. Moreover, the protein levels of β-catenin, cyclin D1, glycogen synthase kinase 3β (GSK-3β) and p-GSK-3β in the brain tissues were detected by Western blot. RESULTS: Compared with cerebral infarction group, the score of neurological function impairment, cerebral infarction volume and brain water content were significantly decreased in stachydrine hydrochloride treatment groups. In addition, the protein levels of β-catenin, cyclin D1 and p-GSK-3β were markedly increased after stachydrine hydrochloride treatment. CONCLUSION: Stachydrine hydrochloride protects against experimental acute cerebral infarction through activation of Wnt/β-catenin signaling pathway.     

Effects of pioglitazone on myocardial energy metabolism and hemodynamics in rats with myocardial infarction

AIM: To observe the effects of pioglitazone on myocardial energy metabolism and hemodynamics in rats with heart failure after myocardial infarction (MI). METHODS: The model of MI was established by ligation of left anterior descending artery. The 20 surviving rats were randomly divided into MI group (n=10) and pioglitazone intervention group (P group,n=10, pioglitazone 3 mg·kg^-1·d^-1 orally). The sham-operated rats (SH, n=10) served as controls. Hemodynamic parameters were measured. The ratio of left ventricular weight to body weight (LVW/BW) and the ratio of right ventricular weight to body weight (RVW/BW) were calculated after 8-week treatment. The expression of PPARγ was examined by Western blotting. Mitochondrial respiratory function was determined by Clark oxygen electrodes. The size of adenine acid pool (ATP, ADP and AMP) in mitochondria was measured by HPLC. The adenine nucleotide translocator(ANT) activity was detected by the atractyloside-inhibitor stop technique. RESULTS: Compared with SH group, the protein expression of PPARγ was significantly decreased in MI group (P<0.01). The mitochondrial respiratory activity, the transport activity of ANT and the high-energy phosphate content were decreased in MI group (P<0.01), and the hemodynamic parameters were in disorder (P<0.01). Compared with MI group, the protein expression of PPARγ in P group was significantly increased. The mitochondrial respiratory activity, the high-energy phosphate content, the transport activity of ANT were improved (P<0.01). However, the hemodynamic parameters were not significantly changed.CONCLUSION: Pioglitazone increases the protein expression of PPARγ and improves myocardial energy metabolism in the development of heart failure in the rat model of myocardial infarction, but dose not change the hemodynamic parameters significantly.     

Salvia extract promotes angiogenesis of myocardium in rats with myocardial infarction

AIM: To determine the effect of salvia extract on angiogenesis of the myocardium in the rats with myocardial infarction (MI) and to analyze its possible mechanism. METHODS: Left coronary artery of Sprague-Dawley rats was ligated to establish a MI model. The rats were randomly divided into MI model group, 3 different dose groups of salvia (10, 20 and 40 mg·kg^-1·d^-1), and sham operation group. Each group consisted of 8 rats. The rats in all treatment groups were orally administered with the salvia extract, and the rats in MI group and sham operation group were fed with the same volume of saline. The rats were sacrificed 4 weeks later. The hemodynamic changes of the rats were determined, and the segmental heart samples were used for morphological observation by hematoxylin and eosin staining, Masson staining, or electron microscopic analysis. The expression of vascular endothelial growth factor (VEGF) and cluster of differentiation 34 (CD34) was analyzed according to immunohistochemistry. RESULTS: Compared with sham operation group, the morphological changes of the myocardium in MI group were disordered, part of myocardial cell outline disappeared, and obvious fibrosis in the necrosis myocardial tissue and fuzzy or disappearing microvascular ultrastructure were also observed. Compared with MI group, the number of new microvessels in all the treatment groups increased obviously, and the morphological changes of the endothelial cells were relatively complete according to electron microscopy. Compared with sham operation group, the protein expression of VEGF and CD34 in the cytoplasm of the myocardial tissues in MI group increased only a little. Compared with MI group, the protein expression of VEGF and CD34 in the cytoplasm of the myocardial tissues in all treatment groups increased significantly (P<0.01). CONCLUSION: Salvia extract obviously promotes angiogenesis of the myocardial tissues in the rats after myocardial infarction.     

Effect of Shenshuguanxin granula on coronary circulation in rats with myocardial infarction

AIM：To explore the effect of traditional Chinese medicine Shenshuguanxin granula on coronary circulation in a rat model of myocardial infarction (MI). METHODS：SD rats (n=50, SPF grade) were randomly divided into 5 groups (n=10):sham group, MI group, and high-dose, middle-dose and low-dose Shenshuguanxin granula treatment groups. The rat MI model was established by ligation of the coronary artery. The cardiac markers, small and medium-sized blood vessels ［microvessel count (MVC) value］ in the infarct zone, and platelet endothelial cell adhesion mo-lecule 1 (PECAM-1) and vascular endothelial growth factor (VEGF) expression in the infarct border zone were measured. RESULTS：After 4 weeks of coronary artery ligation, the significant increases in MVC in the infarct zone, and the expression of PECAM-1 and VEGF in the infarct border zone were detected compared with sham group (P<0.05). The differences of cardiac markers between MI group and other groups were insignificant (P>0.05). CONCLUSION:Shenshuguanxin granula improves coronary circulation in the rats with myocardial infarction by increasing the expression of PECAM-1 and VEGF, and promoting small and medium-sized angiogenesis.     

Correlation between myocardial interstitial collagen remodeling and changes in hemodynamics in rats with myocardial infarction

AIM: To study the relationship between cardiac extracellular matrix remodeling and cardiac function after myocardial infarction. METHODS: We observed sequential changes in collagen contents and collagen Ⅰ/Ⅲ ratios in infarct zone (IZ) and non-infarct zone (NIZ) and their relationship to the parameters of left ventricular systolic and diastolic function in the rat model of myocardial infarction induced by ligation of left main coronary artery. RESULTS: Collagen conteants in IZ and NIZ after 3d of myocardial infarction were significantly higher than those in sham group at corresponding time (P<0.05, P<0.01). Collagen Ⅰ/Ⅲ ratio in IZ decreased on day 3, significantly increased after 7 d (P<0.01). Collagen Ⅰ/Ⅲ ratio in NIZ increased significantly afte14 d. Correlated analysis between collagen contents in IZ or NIZ and collagen type Ⅰ/Ⅲ ratio and maximal ascending velocity (+p'_max) or maximal descending velocity of the left ventricular pressure (-p'_max) was performed and the negative correlation between collagen contents in NIZ and +P'_max (r=-0.589, P>0.05) and -P'_max (r=-0.788, P<0.01) was found. Collagen content in IZ positively correlated to the +P'_max (r=0.70, P<0.50), but not to -P'_max (r=-0.29, P>0.05). Collagen type Ⅰ/Ⅲ ratios in NIZ correlated negatively to the +P'_max (r=-0.504, P>0.05) and -P'_max (r=-0.545, P>0.05), but there were no relationship between collagen type Ⅰ/Ⅲ ratios in IZ and +P'_max or -P'_max in IZ. CONCLUSION: Collagen deposition in IZ after myocardial infarction was of benefit to improvement of systolic function. Collagen deposition in NIZ was harmful to systolic and diastolic function.     

Effects of carvedilol,cilazapril and their combination on left ventricular remodeling after acute myocardial infarction in rats

AIM:To compare the effects of carvedilol, cilazapril and their combination on left ventricular remodeling(LVRM) after acute myocardial infarction(AMI) in rats. METHODS: Twenty-four hours after AMI operation, 100 surviving rats were randomly assigned to: ①AMI control(n= 25), ②AMI+carvedilol(1 mg·kg^-1 ·d^-1, n= 25)(C1), ③AMI+cilazapril(1 mg·kg^-1 ·d^-1, n= 25)(Z1), and ④ AMI+combination(n= 25) groups. Sham-operated group(n= 17) were selected randomly. After 4 weeks of therapy with the drugs gastric gavage, hemodynamic and pathological studies were performed. RESULTS: There were no significant differences in MI size among the four AMI groups(all P> 0.05) Left ventricular(LV) end diastolic pressure(LVEDP), volume(LVV), weight(LVW) and septal thickness(STh) were all higher and left ventricular pressure maximal rate of rise and fall(±d p /d t) were lower(all P< 0.01) in AMI group than sham-operated group. The LVEDP, LVV, LVW and STh were all lower and ±dp /dt were higher in Z1, C1, and combination groups than those in AMI group(P< 0.05, P< 0.01), with LVEDP and STh were more lower in the combination group than in the two monotherapy group(P< 0.05, P< 0.01), but there were no significant differences in other variables among the three therapy groups. CONCLUSION: Carvedilol, cilazapril and their combination all can prevent from LVRM after AMI in rats, improve hemodynamics and LV function, with the combination superior.     

Functional analysis of differential microRNA expression profile in mouse fibrotic liver tissues induced by CCl4

AIM:To discover the expression profile of microRNAs (miRNAs) in mouse fibrotic liver tissues induced by carbon tetrachloride (CCl4), and to investigate the functions of these differential miRNAs based on the gene ontology (GO) analysis and KEGG Pathway analysis. METHODS:The mice were randomly divided into normal group and model group. Liver fibrosis was induced by subcutaneous injection of CCl4. miRNA expression profile of the liver tissues was assayed by a mouse miRNA microarray (Agilent 12.0). The differential expression of miRNAs between the normal and model mice was screened, and GO analysis and KEGG Pathway analysis were performed to determine the functions of these differential miRNAs. RESULTS:Thirty-nine miRNAs with differential expression were discovered in the model mice compared with the normal mice, among which 23 were up-regulated and 16 were down-regulated. GO analysis and KEGG Pathway analysis indicated that most pathological processes of liver fibrosis regulated by miRNAs included cell proliferation and activation, cell apoptosis, cell cycle, cell adhesion, inflammatory reaction, cell migration, transforming growth factor β (TGF-β) signaling pathway, Wnt signaling pathway and proteometabolism process. GO analysis revealed that the key up-regulated miRNAs were mmu-miR-322, mmu-miR-15b, mmu-miR-195, mmu-miR-200b and mmu-miR-214, and the key down-regulated miRNAs were mmu-miR-16, mmu-miR-130a, mmu-miR-101b, mmu-miR-30a and mmu-miR-30e. Analyzing the target genes screened out by GO analysis and Pathway analysis simultaneously, we found that the key up-regulated miRNAs included mmu-miR-200b, mmu-miR-322, mmu-miR-106b, mmu-miR-23a and mmu-miR-15b, and the key down-regulated miRNAs included mmu-miR-16, mmu-miR-30e, mmu-miR-30c, mmu-miR-30a and mmu-miR-130a. CONCLUSION: Differential expression of miRNAs is discovered in mouse fibrotic liver tissues induced by CCl4 compared with the normal liver tissues. Most of the pathological processes involved in liver fibrosis may be regulated by miRNA, such as cell proliferation and activation, cell adhesion and apoptosis, cell migration and differentiation, metabolism, TGF-β receptor signaling pathway and so on.     

Anti-cardiac myosin heavy chain antibodies isolated from patients with acute myocardial infarction induce rat cardiomyocyte apoptosis

AIM: To study the effect of human anti-cardiac myosin heavy chain antibodies (AMHCA) on rat cardiomyocyte apoptosis. METHODS: Rat cardiomyocytes were isolated by the method of enzymolysis. Apoptosis of the cardiomyocytes was observed and measured by DNA end labelling and Annexin-V/PI double-staining assay. The proteins levels of apoptosis related P53 and Bcl-2 and the second messenger calcium were measured by Western blotting, patch clamp and confocal calcium imaging, respectively. RESULTS: AMHCA was able to induce cardiomyocyte apoptosis in a dose dependent manner. In the presence of AMHCA, apoptosis-accelerating nucleoprotein P53 promoted myocardial apoptosis, while apoptosis-inhibiting cytoplasmic protein Bcl-2 inhibited myocardial apoptosis. Meanwhile, the concentration of cytoplasmic calcium was elevated. No effect of AMHCA on L-type calcium currents was observed. CONCLUSION: As a novel triggering factor, AMHCA isolated from the patients with AMI induces cardiomyocyte apoptosis.     

Effects of noninvasive delayed limb ischemic preconditioning on prognosis of myocardial infarction

AIM: To study the effects of noninvasive delayed limb ischemia preconditioning (NDLIP) on animal cardiac function, myocardial morphology and myocardial apoptosis after myocardial infarction (MI). METHODS: Healthy SD male rats[n=45, weighing (250±10) g] were randomly divided into 3 groups:MI group:the animal model of MI was established by surgical ligation of left anterior descending artery (LAD) after 2 weeks; NDLIP group:after the success of the MI animal model, NDLIP was carried out every other day until the 4th, 6th and 8th weeks; sham group:as the negative control group, the animals were taken heart LAD threading but no ligation. All rats were fed conventionally. At the end of the 4th, 6th and 8th weeks, all rats were made ventricular intubation, and then the hemodynamic parameters were recorded. The blood samples were withdrawn from the abdominal aorta and the serum was separated via centrifugation. The serum contents of Bcl-2 and Bax were measured by ELISA. Left ventricular anterior wall was homogenized. The mitochondrial respiratory chain complexes Ⅰ, Ⅱ, Ⅲ and Ⅳ in the myocardial tissues were detected by ELISA. RESULTS: At the end of the 4th, 6th and 8th weeks, compared with MI group, left ventricular systolic pressure in NDLIP group was significantly increased, while left ventricular end-diastolic pressure in NDLIP group was significantly decreased (both P<0.05). Mitochondrial respiratory chain complexesⅠ, Ⅱ, Ⅲ and Ⅳ in NDLIP group were significantly increased (P<0.05). The serum level of Bcl-2 in NDLIP group was significantly increased and Bax level was reduced remarkably (both P<0.01). CONCLUSION: NDLIP improves the hemodynamic indexes, promotes the mitochondrial respiratory function and inhibits cell apoptosis, thus improving the prognosis of MI.     

Expression of urotensin II and its receptor in nephridial tissues of rats with acute renal damage

AIM: To observe the mRNA expression of urotensin II (UII) and its receptor (G protein-coupled receptor 14,GPR14) in nephridial tissues of rats with acute renal damage. METHODS: Male Wistar rats were divided into 2 groups: the rats in control group (n=10) were administered with normal saline by gavage; the rats in model group (n=30) were administered with Caulis Aristolochiae manshuriensis (CAM) by gavage for 25 d to induce acute renal damage. Every 5 rats in model group were sacrificed on the 3rd, 7th, 15th and 25th days during CAM treatment and all rats in the 2 groups were killed 10 d after withdraw of CAM. The kidneys were collected for pathological observation and the UII and GPR14 mRNA examination.RESULTS: The degeneration, necrosis and disintegration in tubules were observed as major pathological changes in the rat kidneys after 3 d of CAM administration. The pathological changes were aggravated following the duration of in CAM administration, and were remained and even worsen when CAM was withdrawn for 10 d. Compared with control group, the mRNA expression of UII was significantly elevated (P<0.05) at the time point of CAM administration for 15 d,even obviously increased (P<0.01) at the time point of CAM administration for 25 d, and remained at the highest levels to the end of the observation. The mRNA expression of GPR14 was significantly increased (P<0.05) at the time point of CAM administration for 7 d, became higher (P<0.01) on the 15th day, and gradually increased as the experimental time went on. CONCLUSION: The mRNA levels of UII and its receptor are significantly elevated in CAM-induced renal lesion in rats, suggesting that UII plays a pathological role in the development of acute renal damage.     

Relationship of microRNA-133a and TGF-β1 protein in myocardial tissues of spontaneously hypertensive rats

AIM：To observe the changes of microRNA-133a and transforming growth factor β1 (TGF-β1) protein in the myocardium of spontaneously hypertensive rats (SHR). METHODS：Male SHR (18 weeks old, n=12) and male Wistar-Kyoto rats (WKY, 18 weeks old, n=12) served as SHR group and control group, respectively. Caudal arterial blood pressure was detected by a noninvasive blood pressure measurement and analysis system. Myocardial collagen volume fraction (CVF) and perivascular collagen area ratio (PVCA) were determined by Masson staining. The level of miR-133a in the heart was detected by real-time quantitative PCR. The protein level of TGF-β1 in the heart was also analyzed by the methods of immunohistochemisty and Western blotting. RESULTS：Compared with control group, systolic and diastolic blood pressure, CVF and PVCA significantly increased, the expression of TGF-β1 protein was significantly up-regulated, and the level of miR-133a was significantly reduced in SHR group. In SHR group, the expression of miR-133a was decreased to (23.9±4.6)% in control group. A negative correlation between the levels of miR-133a and TGF-β1 protein in SHR group was observed (r=-0.791, P<0.01). CONCLUSION：The level of miR-133a is down-regulated along with the up-regulation of TGF-β1 protein expression and collagen synthesis in the myocardial tissues of SHR. miR-133a and TGF-β1 may be involved in myocardial fibrosis in SHR.     

Effect of fluvastatin on left ventricular remodeling after myocardial infarction in rats

AIM: To clarify the protective effect of long-term administration of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor fluvastatin on ventricular remodeling after myocardial infarction (MI) in rats and its mechanisms. METHODS: Myocardial infarction were established by ligated left coronary anterior artery in SD rats, 24 hours after the operation, the survival rats were treated by gavage fluvastatin (20 mg·kg^-1·d^-1) or distilled water for 8 weeks. Doppler echocardiography, homodynamic and cardiac histomorphometry were used to assess the ventricular remodeling and cardiac function. The plasma levels of total cholesterol (Tch), creatinine (Cr), glutamic-oxal (o) acetic transaminase (AST), lipid peroxidation (LPO), glutathione perioxidase (GSH-PX), nitrogen monoxide (NO₂^-/NO₃^-) were detected. RESULTS: The Tch, Cr and AST were not significant difference in groups. Left ventricular end-diastole pressure, right relative weight, left ventricular posterior wall thickness, collagen volume fraction and the lung weight were decreased in AMI+fluvastatin group compared to AMI group (P＜0.05, P<0.01); The levels of LPO, NO₂^-+NO₃^- in plasma and LPO in myocardium decreased, but plasma GSH-PX level increased in AMI+fluvastatin group (P＜0.05). CONCLUSION: Fluvastatin ameliorates the ventricular structural remodeling in a rat model of infarction, and delays the development of heart failure. The anti-oxidation mechanism of fluvastatin may take part in this process.     

Panax quinquefolium saponin attenuates ventricular remodeling after acute myocardial infarction in rats by inhibiting endoplasmic reticulum stress-related apoptosis

AIM: To investigate the effect of Panax quinquefolium saponin (PQS) on ventricular remodeling after acute myocardial infarction (AMI) in rats and its mechanism. METHODS: Ninety healthy male SD rats were randomly divided into sham group, AMI group, taurine 300 mg·kg-1·d-1 group, PQS 50 mg·kg-1·d-1 group, PQS 100 mg·kg-1·d-1 group and PQS 200 mg·kg-1·d-1 group. AMI models were produced by ligating the left coronary arteries in SD rats. The rats in each treatment group were gavaged with drugs dissolved in water (10 mL·kg-1·d-1), and the rats in sham group and AMI group received equal volume of water. Four weeks after MI, the left ventricle fractional shortening, ejection fraction and structure were evaluated by echocardiography. Myocardial infarct size was measured by 2,3,5-triphenyltetrazolium chloride staining. The hydroxyproline level was measured by colorimetric method. Apoptosis of the cardiomyocytes was detected by TUNEL. In addition, the expression of endoplasmic reticulum stress-related molecules in the noninfarcted myocardium was determined by Western blotting. RESULTS: Compared with AMI group, the left ventricular end-systolic dimension in PQS 50 mg·kg-1·d-1 group, PQS 100 mg·kg-1·d-1 group and PQS 200 mg·kg-1·d-1 group decreased by 17.2%, 20.3% and 38.8% respectively,and the left ventricular end-diastolic dimension decreased by 8.91%, 8.95% and 17.20%, respectively.The left ventricular end-systolic volume decreased by 31.4%, 38.5% and 67.0%, respectively, and the left ventricular end-diastolic volume decreased by 18.2%, 18.8% and 34.2%, respectively.The left ventricular ejection fraction increased by 44.9%, 60.1% and 118.0%, respectively,and the fractional shortening increased by 55.4%, 71.0% and 148.0%, respectively.The infarction size decreased by 4.6%, 39.5% and 55.8%, respectively,and the hydroxyproline level in noninfarcted myocardium decreased by 34.5%, 35.9% and 48.7%, respectively. Compared with AMI group, the myocardial apoptotic index in PQS 200 mg·kg-1·d-1 group decreased by 27.3%, the protein expression of Bcl-2 increased by 114.0%, and that of Bax, GRP78, CRT and CHOP decreased by 53.1%, 79.9%, 80.8% and 42.5%, respectively. The above mentioned protective effects in PQS 200 mg·kg-1·d-1 group and taurine group were similar. The Spearman correlation analysis revealed that CHOP expression had significant positive correlation with apoptotic index (r=0.797, P<0.01). CONCLUSION: PQS attenuates ventricular remodeling in rats. The underlying mechanism may be associated with the inhibition of CHOP-mediated endoplasmic reticulum stress-related cardiomyocyte apoptosis.