胰岛素对大鼠结肠平滑肌细胞凋亡及MAPK通路的影响

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

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)信号传导通路的影响。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-P38 MAPK、P38 MAPK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-P38 MAPK、P38 MAPK、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P38 MAPK途径和JNK途径无关。

Objective To study the effects of insulin on the apoptosis and mitogen-activated protein kinase （MAPK） signal transfer pathway of rat colonic smooth muscle ceils （SMCs）. Methods Enzymatic method was used for the isolation and culture of SD rat colonic SMCs; α-actin for immunohistochemical identification; the rat colonic SMCs were treated as normal group, insulin group, and insulin ＋ PD98059 group ; MTF method was used for the detection of SMCs proliferation ; flow cytometric Annexin V-FITC/PI faster for the detection of SMCs apoptosis ; and Western blot was used for the detection of p-ERK, ERK, p-P38 MAPK, P38 MAPK and p-JNK, JNK expressions. Results Compared to the normal group, cells proliferation of insulin group is much was used, apoptosis rate is reduced, p-ERK expression is enhanced and the ratio of p-ERK/ERK is increased（ 110. 36± 9. 5 vs 50.92 ± 6. 01 ） （P 〈 0.01）; and no difference was found in p-P38 MAPK, P38 MAPK, p-JNK and JNK expressions; while in the PD98059 group, cells proliferation is decreased significantly, apoptosis rate is increased, p-ERK expression is inhibited, and the ratio of p-ERK/ERK is decreased （ 15.69 ±2. 11 vs 50. 92 ±6.01 ） （P 〈0. 01 ）. Conclusions Insulin can promote proliferation and inhibit apoptosis in colonic SMCs through activation of the ERK route of MAPK pathway, P38 MAPK and JNK routes may not be involved in this process.