热平衡对小鼠肾脏缺血再灌注后急性肾损伤进程的影响

Effect of thermoneutral housing on the progression of acute kidney injury after renal ischemia-reperfusion in mice

目的探讨热平衡温度(TT)对小鼠单侧肾脏缺血再灌注后肾损伤的影响及其作用机制。方法 8~9周龄的C57/B6雄性小鼠, 根据完全随机法分为常温假手术组(sham 22 ℃), 热平衡温度假手术组(sham 32 ℃), 常温单侧缺血再灌注组(UIR 22 ℃), 热平衡温度单侧缺血再灌注组(UIR 32 ℃)。UIR组取左肾肾蒂夹闭32 min, 再灌注24 h后, 分别置于22 ℃或32 ℃人工气候箱中, 3周后处死小鼠, 留取左肾组织进行组织学、实时荧光定量聚合酶链反应(RT-qPCR)及蛋白质印迹法(Western blot)检测。组间比较采用t检验或方差分析。结果苏木精-伊红(HE)染色示, UIR 32 ℃较之UIR 22 ℃有更严重的肾小管损伤及肾小管、肾间质炎性细胞浸润;胶原纤维(Masson)染色示, UIR 32 ℃较之UIR 22 ℃纤维化更严重;RT-qPCR分析显示, UIR 32 ℃组白细胞介素-1β(IL-1β) (UIR 32 ℃ 36.020±10.750比UIR 22 ℃ 12.410±2.635, t=3.399, P<0.05), 单核细胞趋化蛋白-1(MCP1) (UIR 32 ℃ 155.600±19.380比UIR 22 ℃ 80.020±10.800, t=3.526, P<0.01), 胶原蛋白Ⅲ(ColⅢ) (UIR 32 ℃ 87.480±11.520比UIR 22 ℃ 46.520±5.135, t=3.399, P<0.01)以及转化生长因子β(TGF-β)表达均高于UIR 22 ℃组(UIR 32 ℃ 11.840±0.836比UIR 22 ℃ 8.167±0.767, t=3.239, P<0.01);免疫组织化学显示, UIR 32 ℃组巨噬细胞特异性表面抗原(F4/80)水平高于UIR 22 ℃组(UIR 32 ℃ 148 018.000±29 119.000比33 219.000±7 052.000, t=3.832, P<0.01);Western blot显示UIR 32 ℃组纤黏蛋白(FN) (UIR 32 ℃ 0.986±0.074比UIR 22 ℃ 0.715±0.009, t=1.897, P<0.05), 胶原蛋白Ⅲ(ColⅢ) (UIR 32 ℃ 0.694±0.054比UIR 22 ℃ 0.533±0.047, t=2.253, P<0.05), α平滑肌肌动蛋白(SMAα) (UIR 32 ℃ 1.294±0.096比UIR 22 ℃ 0.971±0.088, t=2.487, P<0.05)等纤维化相关蛋白水平均高于UIR 22 ℃。结论热平衡温度加重小鼠单侧肾脏缺血再灌注后急性肾损伤发展进程, 其机制可能通过加重炎症和纤维化。

Objective To investigate the effects of thermoneutral temperature housing on renal injury after unilateralrenal ischemia-reperfusion(UIR)in mice and its mechanism.Methods C57/B6 male mice aged 8-9 weeks were randomly divided into four groups(8 mice per group):sham operated group of standard housing(sham 22℃),sham operated group of thermoneutral housing(sham 32℃),UIR group of standard housing(UIR 22℃),UIR group of thermoneutral housing(UIR 32℃).UIR was induced by clamping the left renal pedicle for 32 min and then the clamp was removed for reperfusion.At 24 h later,mice were kept in climate chamber at 32℃or 22℃respectively for 3 weeks.Then all mice were sacrificed and kidney tissue was prepared for renal pathology,real-time quantitative polymerase chain reaction(RT-qPCR)and Western blotting analysis.T test or analysis of variance were used for measurement data.Results Hematoxylin-eosin(HE)staining demonstrated that UIR 32℃had exacerbated kidney injury and inflammatory cells infiltration compared to UIR 22℃.Masson staining showed worsened fibrosis in UIR 32℃.RT-qPCR analysis showed higher expression of IL1-β(UIR 32℃36.020±10.750 vs.UIR 22℃12.410±2.635,t=3.399,P<0.05),MCP1(UIR 32℃155.600±19.380 vs.UIR 22℃80.020±10.800,t=3.526,P<0.01),Collagen-Ⅲ(ColⅢ)(UIR 32℃87.480±11.520 vs.UIR 22℃46.520±5.135,t=3.399,P<0.01)and TGF-β(UIR 32℃11.840±0.836 vs.UIR 22℃8.167±0.767,t=3.239,P<0.01)in UIR 32℃group than UIR 22℃group.Immunohistochemical staining demonstrated more F4/80 positive macrophages infiltration in UIR 32℃group than in UIR 22℃group(UIR 32℃148018.000±29119.000 vs.33219.000±7052.000,t=3.832,P<0.01).Western blotting demonstrated more FN(UIR 32℃0.986±0.074 vs.UIR 22℃0.715±0.009,t=1.897,P<0.05),COLⅢ(UIR 32℃0.694±0.054 vs.UIR 22℃0.533±0.047,t=2.253,P<0.05)andα-SMA(UIR 32℃1.294±0.096 vs.UIR 22℃0.971±0.088,t=2.487,P<0.05)accumulation in UIR 32℃group.Conclusion The thermoneutral housing promotes the progression of acute kidney injury after unilateral renal ischemia-reperfusion in mice probable by aggravation of inflammation and fibrosis.