辛伐他汀对慢性心力衰竭兔心肌细胞凋亡的影响

Effects of simvastatin on cardiomyocyte apoptosis in rabbits with chronic heart failure

目的探讨辛伐他汀对慢性心力衰竭(CHF)兔心肌细胞凋亡的影响及其机制。方法将36只新西兰雄性大耳兔随机分为正常对照组、CHF组和辛伐他汀组,每组12只。CHF组和辛伐他汀组兔经耳缘静脉注射注射用盐酸多柔比星1.5 mg·kg^-1,每周1次,连续10周,注射完成后再观察2周;正常对照组兔经耳缘静脉注射生理盐水;辛伐他汀组兔在首次注射多柔比星时开始给予辛伐他汀1.5 mg·kg^-1灌胃,每日1次,连续12周。12周后,3组兔行超声心动图检查,分别测量左心室收缩末期内径(LVESD)、左心室舒张末期内径(LVEDD)、左心室短轴缩短率(LVFS)及左心室射血分数(LVEF)。心脏超声心动图检查后,兔颈动脉取血5 mL,采用酶联免疫吸附试验检测血清可溶性Fas(sFas)水平。采用空气栓塞法处死兔,游离左心室心肌,采用末端脱氧核苷酰基转移酶介导性dUTP切口末端标记法检测心肌细胞凋亡情况,并计算细胞凋亡指数;采用免疫组织化学法检测心肌细胞中p53蛋白表达,并计算p53蛋白阳性表达率。结果辛伐他汀组和CHF组兔LVESD、LVEDD大于正常对照组(P<0.05),LVEF、LVFS显著低于正常对照组(P<0.05);辛伐他汀组兔LVESD、LVEDD小于CHF组(P<0.05),LVEF、LVFS高于CHF组(P<0.05)。正常对照组、CHF组和辛伐他汀组兔血清sFas水平分别为(8.42±0.14)、(11.7±0.55)、(9.43±0.35)mg·L^-1,CHF组和辛伐他汀组兔血清sFas水平高于正常对照组(P<0.05),辛伐他汀组兔血清sFas水平低于CHF组(P<0.05)。正常对照组、CHF组和辛伐他汀组兔心肌细胞凋亡指数分别为1.08±0.12、16.13±1.17、4.86±0.11,CHF组和辛伐他汀组兔心肌细胞凋亡指数高于正常对照组(P<0.05),辛伐他汀组兔心肌细胞凋亡指数低于CHF组(P<0.05)。正常对照组、CHF组和辛伐他汀组兔心肌细胞p53蛋白阳性表达率分别为18.62±0.41、45.39±0.68、33.17±0.52,CHF组和辛伐他汀组兔心肌细胞p53蛋白阳性表达率高于正常对照组(P<0.05),辛伐他汀组兔心肌细胞p53蛋白阳性表达率低于CHF组(P<0.05)。结论辛伐他汀可以显著改善CHF大鼠的心功能,抑制心室重构,其机制可能与其抑制Fas/FasL信号系统及心肌细胞凋亡有关。

Objective To investigate the effect and mechanism of simvastatin on cardiomyocyte apoptosis in rabbits with chronic heart failure(CHF).Methods Thirty-six male immature new Zealand rabbits were randomly divided into normal control group,CHF group and simvastatin group,with twelve rabbits in each group.The rabbits in the CHF group and simvastatin group were injected with doxorubicin hydrochloride 1.5 mg·kg^-1 via ear vein,once a week for 10 weeks,then they were observed for 2 weeks.The rabbits in the normal control group were injected with saline through ear vein.The rabbits in the simvastatin group were injected with simvastatin 1.5 mg·kg^-1 from the first injection of doxorubicin,once a day for 12 weeks.After 12 weeks,the left ventricular end-systolic dimension(LVESD),left ventricular end-diastolic dimension(LVEDD),left ventricular fractional shortening(LVFS)and left ventricular ejection fraction(LVEF)of rabbits in the three groups were measured by echocardiography.After echocardiography,5 mL of carotid artery blood was taken from rabbits and the serum soluble Fas(sFas)level was detected by enzyme linked immunosorbent assay.The rabbits were sacrificed by air embolization to obtain the left ventricular myocardium.Cardiomyocyte apoptosis was detected by terminal deoxynucleotidyl transferase mediated dUTP incision end labeling method,and the apoptotic index was calculated.The expression of p53 protein in cardiomyocytes was detected by immunohistochemistry,and the positive expression rate of p53 protein was calculated.Results The LVESD and LVEDD of rabbits in the simvastatin group and CHF group were higher than those in the normal control group(P<0.05),while the LVEF and LVFS of rabbits in the simvastatin group and CHF group were significantly lower than those in the normal control group(P<0.05).The LVESD and LVEDD of rabbits in the simvastatin group were lower than those in the CHF group(P<0.05),and the LVEF and LVFS of rabbits in the simvastatin group were higher than those in the CHF group(P<0.05).The serum sFas level in the normal control group,CHF group and simvastatin group was(8.42±0.14),(11.7±0.55)and(9.43±0.35)mg·L^-1,respectively.The level of serum sFas in the CHF group and simvastatin group was higher than that in the normal control group(P<0.05),and the level of serum sFas in the simvastatin group was lower than that in the CHF group(P<0.05).The apoptotic index of myocardial cells in the normal control group,CHF group and simvastatin group was 1.08±0.12,16.13±1.17 and 4.86±0.11,respectively.The apoptotic index of cardiomyocytes in the CHF group and simvastatin group was higher than that in the normal control group(P<0.05),and the apoptotic index of cardiomyocytes in the simvastatin group was lower than that in the CHF group(P<0.05).The positive expression rate of p53 protein in myocardial cells of rabbits in the normal control group,CHF group and simvastatin group was 18.62±0.41,45.39±0.68 and 33.17±0.52,respectively.The positive expression rate of p53 protein in cardiomyocytes of rabbits in the CHF group and simvastatin group was higher than that in the normal control group(P<0.05),and the positive expression rate of p53 protein in myocardial cells of rabbits in the simvastatin group was lower than that in the CHF group(P<0.05).Conclusion Simvastatin can significantly improve cardiac function and inhibit cardiac remodeling in rats with CHF,the mechanism may be related to inhibiting Fas/FasL signaling system and cardiomyocyte apoptosis.