线粒体途径在慢性低氧高二氧化碳小鼠骨骼肌凋亡中的作用

Effect of Mitochondrial Pathway in The Apoptosis of Skeletal Muscle of The Mice Exposed to Chronic Hypoxia-hypercapnia

目的探讨线粒体途径在慢性低氧高二氧化碳小鼠骨骼肌凋亡中的作用。方法成年storage protect feature(SPF)级雄性C57BL/6小鼠16只随机分成两组:正常对照组(n=8)和实验组(n=8),将实验组小鼠置于常压低氧高二氧化碳舱内,通过氮气调节舱内氧浓度,使其维持在9%～11%,通入二氧化碳使其浓度维持在5%～6%,每天8h,共4周。用酶联免疫吸附测定法(ELISA)检测骨骼肌细胞胞质内半胱氨酸天冬氨酸特异性蛋白酶3(caspase-3)的含量,荧光实时定量PCR法检测胞浆内细胞色素C(Cyt-C)及细胞凋亡因子Bax、Bcl-2基因的表达情况。结果与正常对照组相比,实验组骨骼肌细胞内的caspase-3含量增加(P<0.05),Cyt-C mRNA表达增多,Bax mRNA表达增多,而Bcl-2 mRNA表达减少,Bcl-2/Bax比值下降。结论线粒体途径可能参与了慢性低氧高二氧化碳小鼠骨骼肌细胞的凋亡,Bcl-2/Bax比值下降可能是促进骨骼肌线粒体途径凋亡的重要因素。

Objective To observe the effect of mitochondrial pathway in the apoptosis of skeletal muscle of the mice which was ex- posed to chronic hypoxia - hypercapnia. Methods Sixteen adult male C57BL/6 mice of storage protect feature （SPF） level were divided randomly into two groups ： the control group （ n = 8 ） and the experiment group （ n = 8 ）. The latter group was placed in the special closed cabin where concentration of oxygen was maintained within 9% - 11% by inputting N2 and concentration of carbon dioxide was regulated within 5% -6% for 8 hours a day, for 4 weeks. Caspase -3 protein was assayed by ELISA, and the expression of Cyt - C mRNA,Bax mRNA and Bcl -2mRNA was analyzed by real -time PCR. Results Compared with the control group, caspase -3 protein was more in- creased in the experiment group and the expression of Cyt - C mRNA and Bax mRNA in the skeletal muscle of the experiment group was more increased,and the expression of Bcl - 2 mRNA was less increased, and the ratio of Bcl - 2/Bax was declined. Conclusion The mi- tochondrial pathway may play an important role in the apoptosis of the skeletal muscle of the mice which exposed to chronic hypoxia - hy- percapnia. The ratio of Bcl - 2/Bax declining may accelerate the occurrence of the apoptosis of mitochondrial pathway.