胰岛素对大鼠结肠平滑肌细胞凋亡及MAPK通路的影响

 目的 探讨胰岛素对大鼠结肠平滑肌细胞( SMCs )凋亡及丝裂原活化蛋白激酶( MAPK )信号转导通路的影响。方法 酶解法分离培养SD大鼠结肠SMCs，α-actin免疫鉴定，将大鼠结肠SMCs分为正常组，胰岛素组，胰岛素 +PD98059( ERK抑制剂)组，MTT法检测SMCs增殖，流式细胞术Annexin V-FITC/PI检测SMCs凋亡，Western blot法检测p-ERK、ERK、p-P38MAPK、P38MAPK和p-JNK、JNK表达。结果 胰岛素组较正常组细胞明显增殖，凋亡率降低，p-ERK表达增强，p-ERK/ERK 比值升高( 110.36 ± 9.5 vs 50.92 ± 6.01 ) ( P < 0.01 )；p-P38MAPK、P38MAPK、p-JNK、JNK表达无差异。PD98059组较正常组细胞增殖明显下降，凋亡率升高，p-ERK表达减弱，p-ERK/ERK比值降低( 15.69 ± 2.11 vs 50.92±6.01 ) ( P < 0.01 )。结论 胰岛素可能通过激活结肠SMCs的MAPK通路中的ERK途径，促进细胞增殖，抑制凋亡，可能与P38MAPK途径和JNK途径无关。

Effects of insulin on the apoptosis and MAPK pathway of rat colonic smooth muscle cells

Objective To study the effects of insulin to the apoptosis and mitogen-activated protein kinase( MAPK ) signal transfer pathway of rat colonic smooth muscle cells ( SMCs ). Methods Enzymatic method for the isolation and culture of SD rat colonic SMCs; α-actin for immunohistochemical identification; division of the rat colonic SMCs into normal group, insulin group, and insulin+PD98059 group; MTT method for the detection of SMCs proliferation; flow cytometric Annexin V-FITC/ PI for the detection of SMCs apoptosis; and western blot for the detection of p-ERK, ERK, p-P38MAPK, P38MAPK and p-JNK, JNK expressions. Results Compared to the normal group, cells proliferation of insulin group is much more significant, apoptosis rate is reduced, p-ERK expression is enhanced, the ratio of p-ERK/ERK is increased( 110.36 ± 9.5 vs 50.92 ± 6.01 ) ( P < 0.01 ); and no differences for p-P38MAPK, P38MAPK, p-JNK and JNK expressions; while for the PD98059 group, cells proliferation is decreased significantly, apoptosis rate is increased, p-ERK expression is weakened, and the ratio of p-ERK/ERK is decreased( 15.69 ± 2.11 vs 50.92 ± 6.01 ) ( P < 0.01). Conclusion Insulin can promote proliferation and inhibit apoptosis in colonic SMCs through activation of the ERK route of MAPK pathway, P38MAPK and JNK routes may not be involved in this process.