探讨尿激酶型纤溶酶原激活物受体(urokinase-type plasminogen activator receptor，uPAR)是否会影响小鼠肾单侧缺血再灌注损伤(unilateral ischemia-reperfusion injury，uIRI)诱导的肾间质纤维化及血管新生。

选取C57BL/6J背景的雌性8~10周龄野生型(wild type，WT)小鼠和uPAR基因敲除(uPAR-knockout, uPAR-ko)小鼠构建肾uIRI模型。实验小鼠分为4组：野生假手术组(WT sham组)、野生单侧缺血再灌注组(WT uIRI组)、uPAR-ko假手术组(uPAR-ko sham组)和uPAR-ko单侧缺血再灌注组(uPAR-ko uIRI组)，5只/组。分别于造模后1 d、3 d、14 d对小鼠取材，检测血清肌酐、血尿素氮和肾脏组织病理学改变；以天狼猩红染色检测肾组织胶原沉积面积，Western印迹法、RT-qPCR和免疫组织化学检测肾组织Ⅰ型胶原蛋白、波形蛋白、E钙黏蛋白、α-平滑肌肌动蛋白及内皮黏蛋白等表达；以免疫荧光检测肾组织血管新生标志物CD31表达。采用双因素方差分析法进行组间比较。

与WT sham组和uPAR-ko sham组分别比较，WT uIRI组和uPAR-ko uIRI组小鼠造模后1 d和3 d的血清肌酐、血尿素氮及肾小管损伤评分均升高(P均<0.05)。与WT uIRI组比较，uPAR-ko uIRI组小鼠造模后1 d和3 d的血清肌酐、血尿素氮及肾小管损伤评分均较高，但造模后14 d的血尿素氮较低(P均<0.05)。与WT sham组和uPAR-ko sham组分别比较，WT uIRI组与uPAR-ko uIRI组小鼠造模14 d后肾组织胶原面积、Ⅰ型胶原蛋白、波形蛋白和α-平滑肌肌动蛋白的蛋白质及mRNA表达均较高，而E钙黏蛋白、内皮黏蛋白及CD31表达均较低(P均<0.05)。与WT uIRI组比较，uPAR-ko uIRI组小鼠的肾组织胶原面积、以及Ⅰ型胶原蛋白、波形蛋白和α-平滑肌肌动蛋白的蛋白质及mRNA表达均较高，而E钙黏蛋白、内皮黏蛋白及CD31表达均较低(P均<0.05)。

uPAR缺失会加重小鼠肾uIRI诱导的肾功能损害及肾间质纤维化，并减少肾脏的血管新生。

To investigate whether urokinase-type plasminogen activator receptor (uPAR) affected renal interstitial fibrosis and angiogenesis induced by renal unilateral ischemia-reperfusion injury (uIRI) in mice.

Female wild-type (WT) mice and uPAR-knockout (uPAR-ko) mice aged 8-10 weeks with C57BL/6J background were selected to construct the renal uIRI model. The experimental mice were divided into four groups: wild-type sham operation group (WT sham group), WT uIRI group, uPAR-ko sham group, and uPAR-ko uIRI group, with five mice in each group. The mice were sampled on days 1, 3, and 14 after modeling to detect serum creatinine, blood urea nitrogen, and renal histopathological changes. Sirius red staining was used to detect collagen deposition area in renal tissues. Western blotting, RT-qPCR, and immunohistochemistry were used to detect the expression of type Ⅰ collagen, vimentin, E-cadherin, α-smooth muscle actin, and endomucin in renal tissues. Immunofluorescence was used to detect the expression of CD31, a marker of angiogenesis, in renal tissues. Statistical comparisons between groups were performed using the two-way analysis of variance.

Compared with the WT sham group and the uPAR-ko sham group, respectively, the WT uIRI group and the uPAR-ko uIRI group showed higher levels of serum creatinine, blood urea nitrogen, and renal tubular injury scores at both 1 day and 3 days after modeling (all P< 0.05). Compared with the WT uIRI group, the uPAR-ko uIRI group exhibited higher levels of serum creatinine, blood urea nitrogen, and renal tubular injury scores at both 1 day and 3 days after modeling, but lower level of blood urea nitrogen at 14 days after modeling (all P<0.05). Compared with the WT sham group and the uPAR-ko sham group, respectively, after 14 days of modeling, the WT uIRI group and the uPAR-ko uIRI group exhibited higher levels of renal tissue collagen area, and higher levels of mRNA and protein expressions of type I collagen, vimentin, and α-smooth muscle actin, but lower levels of protein expressions of E-cadherin, endomucin, and CD31 (all P< 0.05). Compared with the WT uIRI group, the uPAR-ko uIRI group displayed higher level of renal tissue collagen area, and higher levels of protein and mRNA expressions of type I collagen, vimentin, and α-smooth muscle actin, while the protein expressions of E-cadherin, endothelial cadherin, and CD31 were lower (all P< 0.05).

The deficiency of uPAR could exacerbate the kidney dysfunction and renal interstitial fibrosis induced by uIRI, as well as reduced renal angiogenesis in mice.