Giα介导的胰岛素信号转导在烫伤大鼠胰岛素抵抗中的作用

Role of Giαmediated insulin signal transduction in insulin resistance of burned rat

目的 探讨Giα介导的胰岛素信号转导在烫伤大鼠胰岛素抵抗中的作用 ,初步阐明烫伤后发生胰岛素抵抗的信号转导分子机理。方法 ①Western杂交检测严重烫伤大鼠肝脏细胞Giα含量的变化规律 ,并检测烫伤 3d大鼠肝脏细胞IRS 1的酪氨酸磷酸化。②血糖仪和放射免疫法检测烫伤大鼠血糖及胰岛素水平 ,并统计分析与Giα表达水平的关系。结果 ①烫伤后 1～ 6d肝细胞Giα明显降低 ,以伤后第 3天最为明显。同步检测IRS 1的酪氨酸磷酸化 ,发现在胰岛素刺激下IRS 1不能发生酪氨酸磷酸化。②烫伤大鼠血糖和胰岛素水平均明显升高。对烫伤 3d的血糖和Giα进行相关分析 ,发现Giα的表达水平和血糖呈明显的负相关。

Objective To investigate the role of the Giα mediated insulin signal transduction in the burn rats insulin resistance for the mechanism of the resistance. Methods The content of Giα in rat liver cells after severe scald was detected with the Western blot. Blood sugar and insulin were determined with the use of glycometry and radio immunity assay. Results Expression of Giα was decreased obviously in the liver cells from the first to sixth day after scalding, and reached lowest in the third day. Meanwhile, the level of tyrosine phosphorylation of IRS 1 was not increased under insulin stimulation. The level of blood glucose and serum insulin was obviously increased on the third day after scalding. Moreover, there was a significant negative correlation between the concentration of blood glucose and the level of Giα expression. Conclusion Reduction of Giα expression in liver cells in rats after scalding is one of the most important mechanisms by which the impairment of tyrosine phosphorlation of IRS 1 and posttraumatic insulin resistance happen.