1,25(OH)2D3抑制嘌呤霉素氨基核苷酸肾病大鼠足细胞凋亡

目的 观察1，25（OH）2D3对嘌呤霉素氨基核苷酸（PAN）肾病大鼠足细胞凋亡的影响。 方法 72只雄性SD大鼠随机分为健康对照组（NC）、PAN组和1，25（OH）2D3治疗组 1，25（OH）2D3 0.2 μg·kg-1·d-1灌胃]。一次性尾静脉注射PAN 100 mg/kg体质量建立足细胞损伤的PAN肾病动物模型。于3、7、14、21 d分批处死动物，分别检测不同时间点尿蛋白量（24 h）和肾功能。光镜和透射电镜观察肾组织学改变。TUNEL法检测足细胞凋亡。RT-PCR、免疫荧光、免疫组化分别检测nephrin、TGF-β1 mRNA和蛋白的表达。Western印迹检测磷酸化（p）-Smad2/3的表达。 结果 （1）PAN组各时间点BUN、Scr、尿蛋白量（24 h）7 d时，（20.26±4.87） mg比（1.01±0.41） mg，P < 0.01]均高于同期的NC组，而肾小球足细胞显著减少14 d时，(10.9±4.2) 个/肾小球切面比(31.9±6.2)个/肾小球切面，P ＜ 0.01]，且足突增宽融合。1，25（OH）2D3治疗组各时间点尿蛋白量（24 h）7 d时（9.95±3.82） mg]和BUN、Scr显著低于PAN组（P < 0.05），且肾脏病理改变减轻。（2）PAN组7 d时nephrin mRNA和蛋白的表达显著降低，nephrin由正常的沿毛细血管襻线状分布向颗粒状、团快状改变，足细胞凋亡数显著增加14 d时，（37.4±7.9）个/肾小球切面]。与PAN组相比，1，25（OH）2D3治疗组各时间段nephrin mRNA和蛋白的表达显著增加，且保持着正常的沿毛细血管襻线状分布，足细胞凋亡数显著减少14 d时，(21.9±6.2) 个/肾小球切面，P < 0.01]。（3）PAN组TGF-β1 mRNA和蛋白的表达以及p-Smad2/3蛋白的表达均高于NC组（P < 0.01），1，25（OH）2D3治疗组TGF-β1 mRNA和蛋白的表达以及p-Smad2/3蛋白的表达低于PAN组（P < 0.01）。 结论 1，25（OH）2D3能有效地抑制PAN诱导的足细胞凋亡，减少尿蛋白，其对足细胞损伤的保护作用可能与抑制TGF-β1信号通路有关。

Podocyte apoptosis is suppressed by 1,25(OH)2D3 in puromycin aminonudeoside nephropathy rats

Objective To evaluate the effects of 1,25(OH)zD3 on podocyte apoptosis in kidney of puremyein aminonueleoside nephropathy (PAN) rats. Methods Seventy-two male Sprague-Dawley rats were randomly divided into three groups: PAN model group(PAN), 1,25 (OH)2D3 treated group (T, 0.2 μg·kg-1d-1 by garages) and normal control group (NC). PAN rat model was constructed by a single intravenous injection of 100 mg/kg body weight. Renal function and 24hour urinary protein were measured at day 3, 7, 14, 21 after PAN injection. The renal tissue morphology was observed by light and electron microscope. Podocyte apeptosis was evaluated by TUNEL. Protein expressions of nephrin, TGF-β1 and p-Smad2/3 were examined by immunofluoreacence, immunohistochemistry and Western blot, respectively. Results (1)The levels of serum creafinine, BUN and 24-h urinary protein (20.26±4.87) mg vs (1.01±0.41) mg at day 7, P ＜0.01] were significantly higher and the number of glomerular pedocyte was significantly lower (10.9±4.2)/glomerular volume vs (31.9±6.2)/glomerular volume at day 14, P＜0.01] in PAN group compared with NC group. T group rats had less urinary protein excretion (9.95±3.82) mg/24 h, P＜0.01] and more glomerular podocytes compared with PAN group. (2) Distribution of nephrin expression was changed from linear to granular pattern in PAN rats on day 7, nephrin mRNA and protein expressions were markedly decreased(P＜0.01), while the number of apoptotic podocyte was increased in PAN group(P＜0.01). However, higher nephrin expression and less apoptotic podocytes were found in T group (P＜0.01). (3) Compared with NC group, the mRNA and protein expression of TGF-β1 and p-Smad2/3 were higher in PAN group (P＜0.01), while 1,25 (OH)2D3 treatment abrogated PAN-induced changes in the expression of TGF-β1 and p-Smad2/3 (P＜0.01). Conclusions 1,25 (OH)2D3 can significantly suppress PAN-induced podocyte apoptosis and ameliorate proteinnuria. The beneficial effect of 1,25(OH)2D3 on podocyte may contribute to direct suppression of TGF-β signaling.