他克莫司对大鼠胰岛素信号传导分子表达的影响

Effects of tacrolimns on insulin signal transduction

目的通过观察他克莫司对大鼠血糖、胰岛素水平及肝细胞内磷酸化AKT表达的影响，探寻他克莫司导致血糖升高的机制。方法将40只雄性SD大鼠（89.83±4.44）g通过随机数字表法随机分为实验组（他克莫司4 mg·kg-1·d-1灌胃）和对照组（等量生理盐水灌胃），每月测量大鼠体重，行尾静脉穿刺取血测其空腹血糖和他克莫司血药浓度。5个月后，在空腹状态下将2组大鼠分别处死，行心脏穿刺取血，4%多聚甲醛体内灌流分别取出胰腺组织和肝脏组织，采用放射免疫方法测定大鼠的血清胰岛素水平，行胰腺组织病理学观察，用免疫组织化学技术检测肝细胞浆质中磷酸化AKT的表达。结果①实验组与对照组大鼠的体重均呈持续增长，在第3、4、5个月时，实验组大鼠的体重明显低于对照组，且2组的差异有统计学意义（P〈0.05）；②实验组大鼠空腹血糖呈持续增长趋势。在第3、4、5月时，实验组大鼠的空腹血糖水平明显高于对照组（P〈0.05）；③实验组大鼠的胰岛素分泌指数、胰岛素敏感指数明显低于对照组（P〈0.05）；④实验组大鼠与对照组相比，其胰导管均不同程度的受到破坏，且出现胰岛细胞数量减少、坏死及空泡样变；⑤实验组大鼠与对照组相比，其肝细胞浆质内可见磷酸化AKT明显被抑制。 结论他克莫司可导致胰岛细胞坏死，胰岛细胞数量减少，胰岛素的分泌降低、胰岛素敏感性下降、胰岛素抵抗增加，从而导致大鼠血糖升高。他克莫司减少大鼠肝脏组织磷酸化AKT的表达，提示可能通过影响PI3K/AKT信号转导途径导致胰岛素抵抗，引起血糖升高。

ObjectiveTo observe of the effects of tacrolimus on blood glucose, insulin secretion and the expression of phosphorylated AKT in rats in order to study the mechanism of diabetogenic effects of tacrolimus.Methods40 male SD rats were randomly divided into two groups. The rats in tacrolimus group were delivered tacrolimus at a dose of 4mg/kg·d. The rats in the control group were given the same amount of saline solution in the same way. The body weights, fasting blood glucose levels and blood concentrations of tacrolimus were measured monthly. After 5 months, all rats were killed. Pancreas and liver tissue were stored in 4% paraformaldehyde solution. Serum insulin levels were detected by radioimmunoassay method. The expression of phosphorylated AKT in liver were measured by immunohisto-chemical method.Results①The body weights in tacrolimus group in the 3rd, 4th,and 5th month were significantly lower than those in the control group （P〈0.01） . ② The blood glucose levels in tacrolimus group in the 3rd, 4th, and 5th month were significantly higher than those in the control group （P〈0.05） . ③ The insulin secretion and insulin sensitivity index in tacrolimus group were significantly lower than those in the control group （P〈0.01） . ④ The rats in tacrolimus group showed varying degrees of damage in pancreatic duct and pancreatic islet cells. ⑤ The expression of phosphorylated AKT in liver cells in tacrolimus group were significantly lower than those in the control group （P〈0.05） .ConclusionsTacrolimus can induce pancreatic islet cells necrosis, decrease the number of islet cells, reduce insulin secretion and insulin sensitivity, which lead to blood hyperglycemia in rats. In addition, we also find that tacrolimus can reduce expression of phosphorylated AKT in hepatic tissue, which indicates that tacrolimus results insulin resistance through interfering PI3K/AKT signal transduction pathways.