胰岛素对糖尿病小鼠小肠功能的影响

目的 探讨胰岛素(regular insulin,RI)对糖尿病(DM)小鼠小肠功能的影响.方法 一次性给予雄性BALB/c小鼠链脲佐菌素(STZ,150 mg/kg)腹腔注射造模.将造模成功小鼠分为DM组6只,DM+RI组6只,另选血糖正常小鼠6只为对照组.DM+RI组给予RI 40U·kg-1·d-1皮下注射,对照组和DM组每天给予等量的磷酸盐缓冲液(pH=7.4)腹腔注射.所有小鼠干预6周结束后,给予印度墨水灌胃测定胃肠传输速率.免疫组织化学法检测各组小鼠十二指肠组织的c-kit阳性细胞数目.最后处死所有小鼠,用细胞内记录技术记录各组小鼠十二指肠平滑肌细胞内慢波的变化.采用SPSS 17.0软件分析,多组资料间比较采用LSD检验.结果 干预6周后,DM+RI组的多饮、多食、多尿症状比DM组减轻,体重较DM组明显增加(23.33±3.13)g比(15.42±1.40)g,P＜0.01],但比对照组降低(26.78±2.09)g,P＜0.05].第6周DM组血糖值显著高于对照组(P＜0.01),但比DM+RI组显著升高(P＜0.01).DM组小肠推进率比DM+RI组和对照组明显降低(P值均＜0.01);DM+RI组也较对照组降低(P＜0.01).光镜下观察到DM组c-kit阳性细胞数明显低于DM+RI组和对照组(P值均＜0.05),DM+RI组比正常组减少(P＜0.05).DM组慢波频率比DM+RI组和对照组显著降低(P值均＜0.01),而DM+RI组慢波频率比对照组降低(P＜0.01).DM组慢波波幅比DM+RI组和对照组明显降低(P值均＜0.01),而DM+RI组慢波波幅比对照组降低(P＜0.01).结论 DM小鼠存在胃肠动力障碍,外源性RI可能对DM小鼠小肠动力障碍有一定的改善作用.

Abstract：

Objective To investigate the effects of regular insulin (RI)on duodenal smooth muscle in diabetic mice. Methods Diabetes mellitus (DM) model was established by intraperitoneal injection of 150 mg/kg streptozotocin (STZ) in male BALB/c mice. The model mice were divided into DM group and DM treated with RI group with 6 each. Meanwhile, 6 normal mice were served as controls. The mice in treatment group were intraperitoneally injected with 40 U/kg of RI daily.Whereas the mice in DM and control groups were intraperitoneally injected with phosphate buffer solution (pH = 7. 40). After 6 weeks, the small intestinal transit rate of mice was determined by lavage of Indian ink. Interstitial cells of cajal (ICC) in duodenal myenteric plexus were counted using immunohistochemical staining. Slow waves of duodenal smooth muscle cells were recorded with intracellular recordings. Data were analysed by SPSS 17.0 software, and comparisons among three groups were done using LSD test. Results After intervention for 6 months, the clinical presentations,such as more water and food intake and polyuria, were improved in treatment group. The body weight was increased in treatment group (23.33±3.13) g] compared with DM group (15.42±1.40) g,P＜0.01] ,but dereased compared with control group (26.78 ± 2.09) g, P＜0.05]. The level of blood glucose in DM group was significantly higher than that in control and treatment groups(P＜0.01). Small intestine transmission rate was significantly reduced in DM group than that in control and treatment groups (P＜0.01), but it was slower in treatment group than that in control group (P＜ 0. 01 ). Immunohistochemical study showed that the number of c-kit positive cells reduced obviously in DM group than that in control group and treatment group (P＜0.05), whereas it was lower in treatment group than that in control group (P ＜ 0.05). The slow wave frequency and amplitude of duodenal smooth muscle cells in DM group were reduced when compared with control and treatment groups (P＜0.01) and both were lower in treatment group than that in control group (P＜0. 01 ). Conclusion The findings indicate that DM mice have gastrointestinal dysmotility and exogenous insulin may improve small intestinal dysmotility in DM mice.

Effect of insulin on small intestinal smooth muscle in diabetic mice

Objective To investigate the effects of regular insulin (RI)on duodenal smooth muscle in diabetic mice. Methods Diabetes mellitus (DM) model was established by intraperitoneal injection of 150 mg/kg streptozotocin (STZ) in male BALB/c mice. The model mice were divided into DM group and DM treated with RI group with 6 each. Meanwhile, 6 normal mice were served as controls. The mice in treatment group were intraperitoneally injected with 40 U/kg of RI daily.Whereas the mice in DM and control groups were intraperitoneally injected with phosphate buffer solution (pH = 7. 40). After 6 weeks, the small intestinal transit rate of mice was determined by lavage of Indian ink. Interstitial cells of cajal (ICC) in duodenal myenteric plexus were counted using immunohistochemical staining. Slow waves of duodenal smooth muscle cells were recorded with intracellular recordings. Data were analysed by SPSS 17.0 software, and comparisons among three groups were done using LSD test. Results After intervention for 6 months, the clinical presentations,such as more water and food intake and polyuria, were improved in treatment group. The body weight was increased in treatment group (23.33±3.13) g] compared with DM group (15.42±1.40) g,P＜0.01] ,but dereased compared with control group (26.78 ± 2.09) g, P＜0.05]. The level of blood glucose in DM group was significantly higher than that in control and treatment groups(P＜0.01). Small intestine transmission rate was significantly reduced in DM group than that in control and treatment groups (P＜0.01), but it was slower in treatment group than that in control group (P＜ 0. 01 ). Immunohistochemical study showed that the number of c-kit positive cells reduced obviously in DM group than that in control group and treatment group (P＜0.05), whereas it was lower in treatment group than that in control group (P ＜ 0.05). The slow wave frequency and amplitude of duodenal smooth muscle cells in DM group were reduced when compared with control and treatment groups (P＜0.01) and both were lower in treatment group than that in control group (P＜0. 01 ). Conclusion The findings indicate that DM mice have gastrointestinal dysmotility and exogenous insulin may improve small intestinal dysmotility in DM mice.