糖尿病结肠动力障碍近端结肠平滑肌细胞相关凋亡基因表达的研究

摘要

目的:探讨糖尿病(DM)结肠动力障碍近端结肠平滑肌细胞的凋亡变化.方法:雄性SD大鼠36只随机分为正常对照6周组、正常对照10周组、DM 6周组和DM 10周组,每组9只.检测空腹血糖(FBG)、胃肠推进率、血清胰岛素(FINS),HE染色观察近端结肠平滑肌的变化,应用荧光实时定量PCR(Real time-qPCR)检测大鼠近端结肠平滑肌细胞的bax、bcl-2及caspase-3的mRNA表达情况.结果:(1)DM组大鼠较同时间点正常对照组大鼠空腹血糖增高,胃肠推进率及血清胰岛素降低,近端结肠平滑肌变薄,bax及caspase-3的mRNA表达增强,bcl-2的mRNA表达降低,差异有统计学意义(P<0.01).(2)DM 10周组大鼠较DM 6周组大鼠的空腹血糖增高,胃肠推进率及血清胰岛素降低,近端结肠平滑肌变薄,bax及caspase-3的mRNA表达增强,bcl-2的mRNA表达降低,差异有统计学意义(P<0.05).结论:DM结肠动力障碍与近端结肠平滑肌细胞的凋亡密切相关,且细胞凋亡随病程发展而加重.%Objective: To explore the alteration of apoptosis of proximal colon smooth muscle cells in diabetic colon dysmotility. Methods: Thirty-six male SD rats were randomly divided into 4 groups including normal control 6-week group,normal control 1O-week group, diabetes mellitus (DM) 6-week group and DM 1O-week group (n=9 for each). The levels of fasting blood glucose (FBG), gastrointestinal transit rate and the serum level of fasting insulin (FINS) were detected. The changes in the smooth muscle of proximal colon were examined by HE staining. The mRNA expression of bax, bcl-2 and caspase-3 in the proximal colon smooth muscle cells were determined by real-time quantitative PCR (RT-qPCR). Results: (1)There were higher FBG and gastrointestinal transit rate, but lower FINS in DM group than those of control group. The smooth muscle of proximal colon became thinner in DM group than that of control. The mRNA expression levels of bax and caspase-3were significantly higher, but mRNA expression of bcl-2 was lower, in DM group than those of control group (P ＜ 0.01). (2)Compared with DM 6-week group, in DM 1O-week group, there was a higher level of FBG and lower levels of gastrointestinal transit rate and FINS. The smooth muscle of proximal colon became thinner in DM 1O-week group than that in DM 6-week group. The mRNA expression levels of bax and caspase-3 were significantly higher, and of bcl-2 was significantly lower in DM 1O-week group than those in DM 6-week group (P ＜ 0.05). Conclusion: Diabetic colon dysmotility is closely associated with the apoptosis of proximal colon smooth muscle cells, and the apoptosis becomes more significant with the disease development.