eNOS/NO途径在单侧输尿管梗阻小鼠肾间质微血管病变中的作用与机制

目的 探讨内皮型一氧化氮合酶(endothelial nitric oxide synthase, eNOS)和一氧化氮(nitric oxide, NO)在单侧输尿管梗阻(unilateral ureteral obstruction, UUO)肾间质纤维化小鼠微血管病变中的作用及机制。方法 64只KM小鼠随机分为两组:假手术组n=32只;单侧输尿管梗阻UUO组n=32只。观察4周,每周检测各组小鼠血BUN、Scr及一氧化氮,流式细胞计数外周血CD133⁺/VEGFR⁺内皮祖细胞(endothelial progenitor cells,EPCs)、Masson染色观察肾组织形态学变化,免疫组化法检测肾间质CD34⁺表达计数微血管密度,实时定量PCR检测肾皮质eNOS、VEGF mRNA表达。结果 UUO组血一氧化氮、内皮祖细胞计数、肾间质微血管密度、eNOS、VEGF mRNA表达水平持续下降,在第2、3、4周与对照组差异有统计学意义。一氧化氮水平与肾间质微血管密度呈正相关(r=0.715,P<0.05);eNOS mRNA表达水平与肾间质微血管密度(r=0.624,P<0.05)、内皮祖细胞计数(r=0.375,P<0.05)、VEGF mRNA(r=0.351,P<0.05)呈正相关。结论 eNOS/NO途径参与了UUO小鼠肾间质微血管的调节,其调节涉及对血管舒张功能影响、介导促血管肾脏因子VEGF mRNA表达及动员内皮祖细胞等机制。

Role of eNOS/NO signaling pathway in peritubular capillary lesions in renal interstitial fibrosis and the related mechanism in mouse models of unilateral ureteral obstruction

Objective To investigate the role of eNOS/NO signaling pathway in peritubular capillary lesions of mouse renal interstitial fibrosis with unilateral ureteral obstruction (UUC) and the potential mechanism. Methods Sixty-four healthy male KM mice were randomly divided into sham operated group (n=32) and unilateral ureteral obstruction group (n=32). At each week, serum BUN, Scr and NO were determined and the percentages of CD133⁺/VEGFR⁺ endothelial progenitor cells in peripheral blood mononuclear cells were detected by flow cytometry. Morphological changes of the renal tissue were observed using Masson staining. The expression of CD34⁺ cells in the renal interstitium was analyzed by immunohistochemistry to calculate the peritubular capillary density. The expressions of eNos and VEGF mRNA were determined by real-time PCR. Results The expression of blood NO, the percentages of endothelial progenitor cells, peritubular capillaries, eNOS mRNA, and VEGF mRNA in the UUO group were significantly decreased compared with those of the sham group at 2, 3, and 4 weeks (P<0.05). NO was positively correlated with peritubular capillaries (r=0.715, P<0.05), eNOS mRNA was positively correlated with peritubular capillaries (r=0.624, P<0.05), endothelial progenitor cells (r=0.375, P<0.05), and VEGF mRNA (r=0.351, P<0.05). Conclusions eNOS/NO signaling pathway participates in regulation of peritubular capillary lesions in renal interstitial fibrosis of UUO mice. The mechanism may be partly related to the regulation of vasomotor reflex, the expression of VEGF mRNA and mobilization of endothelial progenitor cells.