摘要
目的:观察不同剂量阿霉素心脏毒性心肌细胞凋亡情况及相关基因bcl-2,bax蛋白表达变化。方法:实验于2005-06/2006-08在大连医科大学附属第二医院实验中心完成。选用健康新西兰纯种白兔42只,按随机数字表法分成4组:①对照组(n=10),给予2mL/kg的生理盐水静脉注射,1次/周,共8周。②阿霉素4mg/kg组(n=10),给予阿霉素2mg/kg,以生理盐水稀释耳缘静脉注射,1次/周,共2周。③阿霉素8mg/kg组(n=10),同样方法给予阿霉素,共4周。④阿霉素16mg/kg组(n=12),同样方法给予阿霉素,共8周。12周后麻醉处死兔,取心肌组织,应用原位末端标记法标记凋亡的心肌细胞;应用免疫组织化学法检测bcl-2,bax蛋白的表达,以平均吸光度表达。结果:阿霉素16mg/kg组兔死亡3只,最后39只兔进入结果分析。①透射电镜观察结果:对照组、阿霉素4mg/kg组未见心肌细胞凋亡;阿霉素8mg/kg组和阿霉素16mg/kg组均观察到细胞核变小、核染色质浓缩、边聚的凋亡心肌细胞。②心肌细胞凋亡指数:对照组、阿霉素4mg/kg组未见心肌细胞凋亡;阿霉素8mg/kg组和阿霉素16mg/kg组心肌细胞凋亡指数显著高于对照组(P<0.01)。③心肌bcl-2与bax蛋白表达:阿霉素8,16mg/kg组bcl-2蛋白表达显著低于对照组(P<0.01),bax蛋白表达显著高于对照组(P<0.01),bcl-2/bax显著低于对照组(P<0.01)。阿霉素16mg/kg组bcl-2蛋白表达显著低于阿霉素8mg/kg组(P<0.01),bax蛋白表达显著高于阿霉素8mg/kg组(P<0.01)。与对照组相比,阿霉素4mg/kg组bcl-2,bax蛋白表达及bcl-2/bax无明显变化(P>0.05)。结论:阿霉素4mg/kg组可能因阿霉素剂量小未出现心肌细胞凋亡,阿霉素8,16mg/kg组可见典型凋亡心肌细胞,并且呈一定的量效关系,进一步说明细胞凋亡机制参与了阿霉素心脏毒性的病理过程,其作用与下调bcl-2基因的蛋白表达、上调bax基因的蛋白表达有关。
AIM： To study cardiomyocyte apoptosis and the expressions of bcl-2 and bax protein in adriamycin （ADM）-induced myocardial damage in rabbits treated with different doses of ADM. METHODS： The experiment was conducted in the Experimental Center of the Second Affiliated Hospital of Dalian Medical University from June 2005 to August 2006. Forty-two New Zealand purebred white rabbits were stochastically divided into four groups： ①Control group （n =10）： Rabbits received 2 mL/kg normal saline by intravenous injection, once a week for 8 weeks.②ADM at 4 mg/kg group, 8 mg/kg group and 16 mg/kg group （n =10, 10, 12）： Rabbits were given 2 mg/kg ADM, which was diluted with normal saline intravenously, once a week for 2, 4 and 8 weeks, respectively. Twelve weeks later, rabbits were executed under anesthesia, apoptotic cardiomyocytes were detected using the terminal deoxynucleotidyl transferase mediated dUTP nick end labeling （TUNEL） method. The expressions of bcl-2 and bax protein were determined by immunohistochemical method through mean absorbance. RESULTS： Except 3 deaths in ADM at 16 mg/kg group, other 39 rabbits were all involved in the result analysis.①Observation by transmission electron microscope： There were no apoptotic cardiomyocytes in control group and 4 mg/kg group, however apoptotic cardiomyocytes were found in 8 mg/kg group and 16 mg/kg group, appearing cellular nucleus shrank and nuclear chromatin condensed. ②The index of apoptotic cardiomyocytes increased significantly in 8 mg/kg group and 16 mg/kg group compared with control group （P〈 0.01）. ③Compared with control group, the expression of bcl-2 protein was significantly lower in 8 mg/kg group and 16 mg/kg group （P〈 0.01）, the expression of bax protein was significantly higher （P 〈 0.01）, and bcl-2/bax was significantly lower. The expression of bcl-2 protein was significantly lower in 16 mg/kg group than in 8 mg/kg group （P 〈 0.01 ）, however the expression of bax protein was significantly higher （P 〈 0.01）. The expressions of bcl-2 and bax protein together with bcl-2/bax in 4 mg/kg group were closed to those in control group （P〉0.05）. CONCLUSION： There is no apoptotic cardiomyocytes in ADM 4 mg/kg group due to low dose, and typical cardiomyocyte apoptosis is found in 8 and 16 mg/kg groups, presenting in a dose-effect manner. It is indicated that cardiomyocyte apoptosis is an important pathological mechanism of ADM-induced myocardial damage, and the effect may be related to the down-regulation of bcl-2 protein expression and up-regulation of bax protein expression.
出处
《中国组织工程研究与临床康复》
CAS
CSCD
北大核心
2007年第29期5717-5720,共4页
Journal of Clinical Rehabilitative Tissue Engineering Research
基金
辽宁省教育厅科学研究计划(05L109)~~
