JAK-STAT通路在小鼠单侧输尿管梗阻模型肾间质纤维化中的作用

目的 探讨Janus蛋白酪氨酸激酶-信号转导子和转录激活子(JAK-STAT)通路在小鼠单侧输尿管梗阻(UUO)模型.肾间质纤维化过程中的作用.方法 选用30只雄性Balb/c小鼠建立小鼠UUO模型(n=24)和假手术小鼠(n=6),术后第1、4、7和14天检测JAK-STAT磷酸化情况.另把18只雄性Balb/c小鼠随机分为假手术组、UUO模型组和治疗组,每组各6只.治疗组在建模前2 h开始给予选择性JAK2抑制剂AG490治疗,每天1次;模型组仅注射溶媒.术后第14天处死动物.组织学评估肾小管损伤和.肾间质纤维化程度;免疫组化检测肾脏巨噬细胞浸润和α-SMA表达;RT-PCR检测Ⅲ型胶原和单核细胞趋化蛋白(MCP)1 mRNA表达;Western印迹检测JAK2和STATl磷酸化.结果 JAK2-STAT1在UUO模型中被激活,其磷酸化水平与病情、肾小管组织学损害以及.肾间质纤维化相一致.AG490能显著抑制JAK2和STAT1的磷酸化(P＜0.01).AG490治疗显著减轻肾小管损害[(21.7±1.7)%比(49.4±1.0)%]和肾间质纤维化(1.0±0.1比2.3±0.2)、α-SMA表达(0.9±0.1比2.1±0.2)和巨噬细胞积聚[(13.3±1.6)细胞/HPF比(34.4±1.0)细胞/HPF](均P＜0.01).AG490治疗显著抑制Ⅲ型胶原和MCP-1 mRNA表达.结论 JAK-STAT信号通路在肾小管间质炎性反应和纤维化中发挥重要作用.

Role of JAK-STAT signaling in the interstitial fibrosis of unilateral ureter obstruction mice

Objective To study the role of JAK-STAT singal transduction pathway in the interstitial fibrosis of unilateral ureter obstruction (UUO)mice. Methods Mice UUO model was established and the phosphorylation of JAK-STAT was examined at day 1,4,7 and 14 after ligation of the ureter.Mice in the treatment group were treated with daily injection of selective JAK2 inhibitor AG490 starting 2 h before ureter ligation until sacrifice while vehicle alone was given to mice in the model control group.Mice were sacrificed at day 14 after the establishment of model.Renal tubular lesion and interstitial fibrosis were assessed on paraffin section.Immunohistochemistry was used to detect renal macrophage infihration and α-SMA expression.The expression of collagen Ⅲ and MCP-1 mRNA was measured by RT-PCR.Phosphorylation of JAK2and STAT1 was examined by Western blotting. Results JAK2-STAT1 signaling transduction pathway was activated in UUO model.The activation of JAK2-STAT1 was closely correlated with the progression of renal injury,tubular histological lesions and interstitial fibrosis.AG490 treatment significantly inhibited the phosphorylation of JAK2 and STAT1 (P＜0.01).AG490 treatment also significantly reduced tubular lesions[(21.7 ±1.7)% vs (49.4±1.0)%]and interstitial fibrosis(1.0±0.1 vs 2.3±0.2),α-SMA expression(0.9±0.1 vs 2.1±0.2)and maerophage accumulation[(13.3±1.6)cells/HPF vs (34.4±1.0)cells/HPF](all P＜0.01).In addition,AG490 significantly inhibited the expression of collagen Ⅲ and MCP-1 mRNA. Conclusion JAK-STAT signaling plays an important role in renal tubulointerstitial inflammation and fibrosis.