糖尿病胃轻瘫大鼠胃平滑肌细胞膜G蛋白基因表达的变化

目的 探讨胃平滑肌细胞内信号传导异常在糖尿病胃轻瘫发病机制中的作用.方法 健康雄性SD大鼠20只随机分为两组,每组10只,分别为健康对照组、糖尿病模型组,四氧嘧啶50 mg/kg静脉注射1次,建立大鼠糖尿病模型,健康对照组仅注射等量0.9%氯化钠注射液.营养性半固体米糊法测定胃排空率.放射免疫方法测定胃平滑肌细胞cAMP含量.核酸原位杂交方法和计算机图像分析系统对平滑肌细胞的Gsα、Giα mRNA的表达进行定量分析.结果 (1)胃排空率:模型组较对照组明显减低(P<0.05);(2)胃平滑肌cAMP含量:模型组较对照组明显增高(P<0.05);(3)Gsα、Giα的基因表达量:Gsα mRNA阳性物质星棕黄色颗粒,位于平滑肌细胞胞浆内,模型组的表达量明显高于健康对照组(P<0.05);Giα mRNA阳性物质呈亮红色颗粒,位于胞浆内,两组之间的表达量差异无统计学意义(P>0.05).结论 糖尿病大鼠胃平滑肌Gsα mRNA的表达量变化可能在糖尿病胃轻瘫的发病机制中起一定作用.

Expression of G-protein gene in rats with diabetic gastroparesis

Objective To investigate the possible role of abnormal signal transduction in smooth muscle cell in the pathogenesis of diabetic gastroparesis. Methods Healthy male SD rats were randomly divided into 2 groups: normal,model group,diabetes was induced by Ⅳ of alloxan,50mg/kg. Gastric emptying was measured by method of nutritious semisolid paste. The level of cAMP in gastric smooth muscle cell was measured by radioimmunoassay. Gsαand GiαmRNA positive cells were quantitatively measured by in situ hybridization and computer image analysis system respectively. Results ( 1 ) Gastric emptying rate of the normal was significantly higher than that of model group (P < 0.05 ) ; (2)the level of cAMP of the normal was significantly lower than that of model group( P < 0.05 ) ; (3)the expression of GsαmRNA in the model group was significantly higher than that of the normal groups( P < 0.05 ) ; (4) there was no marked difference in the expression of GiαmRNA between 2 groups( P > 0.05). Conclusion Altered expression of GSαmRNA may play a key role in the pathogenesis of diabetic gastroparesis.