阻断JAK2／STAT3信号通路对尿毒症腹膜透析大鼠腹膜组织上皮细胞间充质转分化的影响

Effect of the JAK2/STAT3 signaling pathway on epithelial mesenchymal transition of the peritoneum in uremic peritoneal dialysis rats

目的探讨JAK2／STAT3信号通路是否参与了尿毒症腹膜透析（PD）大鼠腹膜间皮细胞上皮细胞-间充质转分化（EMT）。方法Sprague—Dawley雄性大鼠按照随机数字表法被分为6组：正常对照组、假手术组、尿毒症组、腹膜透析组、S3I-201对照组、S3I-201组，每组均8只。构建5／6肾切除尿毒症腹膜透析大鼠模型，腹膜透析组、S3I-201对照组、S3I-201组每天经腹透管注人4．25％葡萄糖腹膜透析液（3ml／100g体重），S3I—201组大鼠隔天经腹透管注入STAT3抑制剂S3I-201（2．5mg/kg），同时S3I-201对照组经腹透管注入等量的S3I-201溶剂。透析28d后分别检测腹膜功能、腹膜病理变化和毛细血管密度（MVD），血液和腹透液中的肌酐值和IL-6浓度，大鼠腹膜组织中p-JAK2、p-STAT3的活化状态，以及E—cadherin、α-SMA和VEGFmRNA和蛋白的表达。结果与正常对照组相比，尿毒症组和腹膜透析组大鼠腹膜功能呈现超滤衰竭状态，腹膜厚度和MVD增加，透析液和血清中IL-6浓度升高，E—cadherin表达降低，α-SMA、VEGF、p—JAK2和P—STAT3的表达升高。与尿毒症组相比，腹膜透析组腹膜功能进一步恶化，腹膜厚度和MVD增加（均P〈0．01），透析液和血清中IL-6浓度升高（均P〈0．01），E—cadherin表达降低，α-SMA、VEGF、p-JAK2和p-STAT3的表达升高。S3I-201对照组与腹膜透析组相比较，各指标差异均无统计学意义（均P〉0．05）。与S3I-201对照组相比，S3I-201组腹膜功能得到改善，腹膜厚度和MVD减少（均P〈0．01），透析液和血清中IL-6浓度降低，E．cadherin mRNA和蛋白表达增加（均P〈0．05），α-SMA、VEGF、p-JAK2和p-STAT3mRNA和蛋白的表达降低（均P〈0．05）。结论抑制STAT3后，腹膜透析大鼠腹膜厚度、血管新生和IL-6浓度均降低，EMT也被抑制，腹膜功能得到改善。因此，JAK2／STAT3信号通路可能通过调节IL-6的表达参与尿毒症腹膜透析大鼠腹膜组织EMT。

Objective To investigate whether the JAK2/STAT3 signaling pathway is involved in the epithelial- mesenehymal transition （EMT） of peritoneal mesothelial ceils in uremic peritoneal dialysis （PD） rats. Methods A total of 48 male Sprague-Dawley （SD） rats were randomly separated into six groups： normal control group （NC group, n=8）, sham group （n=8）, uremic group （n=8）, PD group （n=8）, S3I- 201 control group （n=8） and S3I- 201 group （n=8）. Uremic model generated by 5/6 nephrectomy surgery in rats was established. The rats of PD group, S3I-201 control group and S3I-201 group received daily infusion of 4.25% glucose-based peritoneal dialysate fluid （3 ml/100 g） from PD catheters for 28 days. Rats of S3I-201 group were injected with STAT3 inhibitor S3I-201 （2.5 mg/kg） solution fl＇om the catheters every other day; the same dose of the solvent of S3I-201 was simultaneously given to S3I-201 control group rats. After PD for 28 days, peritoneal function, pathologic changes, and microvessel density （MVD） were evaluated. Creatinine, urea nitrogen and iuterleukin- 6 （IL- 6） concentration in blood and dialysate, and protein and mRNA levels of phospho- JAK2 （p- JAK2）, phospho-STAT3 （p-STAT3）, E-cadherin, alpha-smooth muscle actin （α-SMA） and vascular endothelial growth factor （VEGF） in peritoneum were determined. Results Uremia and peritoneal dialysate could aggravate the peritoneal function and elevate peritoneal thickness and MVD. They could also increased the concentration of IL-6 in blood and dialysate and the expression levels of α-SMA, VEGF, p- JAK2 and p- STAT3 in peritoneum, while lowering E- cadherin expression in peritoneum. These manifestations were even more remarkable in PD group compared to those in uremic group. There was no statistical difference between the S3I-201 control group and the PD group as regards all the index （all P 〉 0.05）. Compared with the S3I-201 control group, the rats treated with S3I-201 showed better peritoneal function. S3I- 201 could reduce peritoneal thickness （P 〈 0.05）, MVD （P〈 0.05）, the concentration of IL-6 in blood and dialysate, the mRNA and protein expression of α-SMA, VEGF, p- JAK2 and p-STAT3 （all P 〈 0.05）, while enhance the mRNA and protein expression of E-cadherin （all P 〈 0.05）. Conclusions After STAT3 is inhibited, the peritoneal thickness, MVD and IL- 6 concentration in PD rats are decreased, and EMT is also inhibited, while peritoneal function is improved. The JAK2/STAT3 signaling pathway may thus be involved in the process of EMT of peritoneum in uremic peritoneal dialysis rats by regulating the expression of IL-6.