抑制JAK/STAT信号通路对糖尿病早期大鼠视网膜Müller细胞的保护作用及对谷氨酸转运蛋白表达的影响

Inhibition of JAK/STAT signaling pathway protects retinal Müller cells and affects the expression of glutamate transporter in early diabetic rats

目的探讨JAK/STAT信号通路对糖尿病早期大鼠视网膜Müller细胞及对谷氨酸转运蛋白(glutamate transporter,GLAST)表达的影响。方法雄性SD大鼠30只,随机分成对照组、糖尿病组、AG490组,每组10只。后两组大鼠采用单次腹腔注射链脲佐菌素(streptozotocin,STZ) 50 mg·kg^(-1)诱导糖尿病模型。模型诱导成功后,AG490组给予AG490 10μL(17 mmol·L^(-1))玻璃体内注射给药。注射1个月后,利用试剂盒检测3组大鼠视网膜中谷氨酸含量变化,免疫荧光检测视网膜GLAST表达,免疫组织化学检测视网膜p-JAK2表达,Western blot检测视网膜GLAST、p-JAK2及p-STAT3蛋白相对表达量。结果与对照组GLAST相对表达量(65. 35±0. 66)%、p-JAK2相对表达量(32. 80±0. 40)%、p-STAT3相对表达量(17. 62±1.09)%、谷氨酸含量(23. 93±0. 67)μmol·g^(-1)相比,糖尿病组视网膜p-JAK2相对表达量(52. 16±0. 62)%、p-STAT3相对表达量(47. 41±0. 95)%及谷氨酸含量(44. 88±0. 27)μmol·g^(-1)均明显增加,GLAST相对表达量(32. 96±0. 64)%明显下降(均为P <0. 01);而与糖尿病组相比,AG490组p-JAK2相对表达量(13. 67±0. 45)%、p-STAT3相对表达量(14. 47±0. 25)%及谷氨酸含量(25. 18±0. 66)μmol·g^(-1)均明显降低,GLAST相对表达量(49. 48±0. 32)%明显增加(均为P <0. 01)。结论糖尿病早期大鼠视网膜GLAST表达明显降低,抑制JAK/STAT通路的活化可上调视网膜GLAST表达,降低视网膜谷氨酸含量,这可能有助于减轻糖尿病状态下视网膜Müller细胞的损伤。

Objective To investigate the effects of JAK/STAT signaling pathway on the expression of glutamate transporter(GLAST)and Müller cells in early diabetic rats.Methods Thirty clean grade male SD rats were divided into control group,diabetes group and AG490(JAK2 inhibitor)group according to the random number method,10 rats in each group.The diabetic model was induced by streptozotocin(STZ)(50 mg·kg^-1)for the rats in the latter two groups.The AG490 group was given AG490 10μL(17 mM)by intravitreous injection.One month later,the content of glutamate in retina was detected by kits.The expression of GLAST was detected by immunofluorescence.The expression of p-JAK2 was detected by immunohistochemistry.The relative expression of GLAST,p-JAK2 and p-STAT3 was detected by Western blot.Results Compared with the expression levels of GLAST[(65.35±0.66)%],p-JAK2[(32.80±0.40)%],p-STAT3[(17.62±1.09)%]and the content of glutamate[(23.93±0.67)μmol·g^-1]in control group,the expression levels of p-JAK2[(52.16±0.62)%],p-STAT3[(47.41±0.95)%]and the content of glutamate[(44.88±0.27)μmol·g^-1]in diabetic group were significantly increased,and the expression level of GLAST[(32.96±0.64)%]was significantly decreased(all P<0.01).Compared with diabetes group,the expression levels of p-JAK2[(13.67±0.45)%],p-STAT3[(14.47±0.25)%]and the content of glutamate[(25.18±0.66)μmol·g^-1]were decreased significantly in AG490 group,and the expression level of GLAST[(49.48±0.32)%]was increased significantly(all P<0.01).Conclusion Inhibition of JAK/STAT pathway activation can up-regulate the expression of GLAST and decrease the content of glutamate in retina,which may help to reduce the damage of retinal Müller cells in diabetic rats.