Ⅱ型糖尿病猕猴部分靶器官中Th1/Th2型细胞因子表达分析

Expression of Th1/Th2 cytokines in partial target organs of type 2 diabetes mellitus rhesus monkey

检测Ⅱ型糖尿病猕猴部分靶器官中Ⅰ型辅助T细胞(Th1)因子IL-2和IFN-γ以及Ⅱ型辅助T细胞(Th2)因子IL-4、IL-10的表达及分布变化情况,研究Th1/Th2型细胞因子在Ⅱ型糖尿病发病中的变化。取Ⅱ型糖尿病及健康猕猴胰腺、肝、肾和心脏,通过石蜡切片、常规染色观察病理变化,同时采用免疫组织化学SABC法检测各靶器官IL-2、IFN-γ、IL-4和IL-10的表达及分布情况。病理结果显示:糖尿病猕猴肝血窦增宽伴中性粒细胞浸润,肾、心脏和胰腺细胞呈不同程度肿胀、萎缩及坏死。免疫组织化学结果显示:在肾中Th1型细胞因子IFN-γ表达水平高于健康组(P<0.01)并分布于近曲小管、远曲小管及集合管。胰腺中IFN-γ表达水平与健康组相比差异无统计学意义(P>0.05),阳性产物分布于胰岛部及外分泌部。胰腺及肾中Th1型细胞因子IL-2表达水平与健康组相比差异无统计学意义(P>0.05)。胰腺及肾中Th2型细胞因子IL-4表达水平显著低于健康组(P<0.01),阳性产物分布于远曲小管、胰腺胰岛及外分泌部。在胰腺、肾、肝及心脏中,Th2型细胞因子IL-10表达水平显著高于健康组(P<0.01),阳性产物分布于近曲小管、远曲小管、胰腺胰岛、胰腺外分泌部、心肌细胞及肝细胞的胞质中。Th1/Th2型细胞因子在Ⅱ型糖尿病(type 2diabetes mellitus,T2DM)的发病过程中发生了显著变化。

Summary Type 2diabetes mellitus（T2DM）is a disease caused by carbohydrate metabolism disturbance,insulin resistance and reduction of insulin.Many studies confirmed that the disequilibrium of Th1/Th2 cells concerned with T2 DM.IL-2and IFN-γmediate the growth of Th1 cells which induce cellular immunity.IL-4and IL-10 are key mediators of Th2 cells which play an important role in humoral immunity.The principal goal of the present researchis to detect the changes of Th1/Th2 cytokines in the pathogenesis of T2 DM.Five male healthy rhesus monkeys and five male T2 DM rhesus monkeys induced by high-fat diets were used in the study.All rhesus monkeys had been checked without any infections such as bacteria and parasite before trials.After induced for 24 months,the fasting plasma glucose（FPG）mean value of all T2 DM rhesus monkeys was higher than 7.0mmol/L,and that of the control rhesus monkeys was below 6.11mmol/L.Typical symptoms of type 2diabetes mellitus were also observed in T2 DM rhesus monkeys.The FPG met the WHO and ADA standards for type 2diabetes mellitus.Animals were scarified after ketamine anesthesia.Target organs（liver,kidney,heart and pancreas）were fixed in paraformaldehyde,embedded in paraffin and sliced.The pathological changes were studied by hematoxylin-eosin staining,and the expressions of IL-2,IFN-γ,IL-4and IL-10 were observed by immunohistochemistry.Mean density was measured by IPP 6.0（Image-pro plus 6.0）to evaluate their variation.Neutrophil cell infiltration which means chronic inflammation was observed in hepatic sinusoid of T2 DM rhesus monkeys,and hepatic sinusoid of T2 DM was wider than healthy rhesus monkeys.Different degrees of cellular swell and atrophy as well as necrosis were found in kidney,heart and pancreas.All the tested organs in the study were damaged in the process of T2 DM.IL-2,IL-4and IFN-γwere only expressed in kidney and pancreas,and IL-10 was expressed in all the four organs.IL-2was only expressed in langerhans islet and kidney tubules,but IFN-γ,IL-4and IL-10 were expressed in endocrine and exocrine pancreas,kidney tubules.IL-10 was also expressed in hepatic and myocardial cell.The expression of IFN-γand IL-10 were significantly increased（P0.01）,but IL-4was decreased oppositely（P0.01）.The expression of IL-2in pancreas and kidney had no difference between T2 DM and health rhesus monkeys（P0.05）.In conclusion,IL-2,Th1 cytokines,has no significant change,but IFN-γof Th1 cell is expressed higher in T2 DM.Simultaneously,IL-4and IL-10,Th2 cytokines,change oppositely.Inflammation exists in the process of T2 DM.Difference distribution and level of Th1/Th2 cytokines between T2 DM and health rhesus monkeys show that Th1/Th2 cell disequilibrium is key mediators in T2 DM.According to the complex changes of cytokines of Th1/Th2 cells,it needs further researches to define the relationship of Th1/Th2 balance with T2 DM.