雷帕霉素减少GK糖尿病大鼠肾脏细胞凋亡及其机制

Rapamycin relieves apoptosis of renal cells in GK diabetic rats and the relative mechanisms

目的观察糖尿病肾组织肿瘤坏死因子(TNF-α)、核因子(NF-κB)的表达及其与肾组织细胞凋亡关系以及雷帕霉素对其的影响。方法将20只GK大鼠随机分为DM组(n=10)、DMR组(n=10),10只Wistar大鼠作为NC组。DMR组予以6mg/kg雷帕霉素灌胃,DM与NC组仅给予等量生理盐水灌胃。TUNEL法检测肾组织细胞凋亡。免疫组织化学法(IHC)检测肾组织TNF-α和NF-κB的表达。结果 TUNEL法显示,NC组肾组织未见明显的凋亡细胞;4周及8周DM组凋亡数呈进行性增多(P<0.01)。IHC显示,NC组肾组织TNF-α、NF-κ Bp65有轻微阳性表达;4周、8周DM组NF-κBp65、TNF-α表达有逐渐上升的趋势,均显著高于正常对照组(P<0.01)。NF-κ Bp65、TNF-α阳性表达呈正相关(P<0.01);肾组织NF-α和NF-κ Bp65表达与肾组织细胞凋亡之间均呈正相关(P<0.01);与DM组比较,DMR组4周、8周组肾组织TNF-α和NF-κ Bp65的过度表达均被显著抑制(P<0.01),肾组织细胞凋亡数显著减少(P<0.01)。结论 NF-κB及其诱导的TNF-α在糖尿病肾病损伤中发挥重要作用,雷帕霉素可能通过抑制NF-κB和TNF-α的表达减少减轻肾组织细胞凋亡。

Objective To observe whether rapamycin can relieve apoptosis of renal cells in GK diabetic rats. Methods Ten male Wistar rats and ten male GK rats were randomly divided into three groups： normal control （NC, n = 10 ） , diabetics （DM, n= 10 ） and diabetics treated with rapamycin （DMR,n= 10）. The renal cell apoptosis was measured by TUNEL. The expression of TNF-α and NF-κB in renal tissue were examined by irnmunohistochemical stain. The correlation between TNF-α and NF-κB were analyzed by Pearson method, and the interrelation between TNF-α, NF-κB and renal tissue apoptotic cells was analyzed by Spearman method. Results The apoptotic renal cell number was more in DM 4w and 8w groups than in NC group and in rapamycin-treated DM group （DMR） （all P〈0.05） and was more in 8w group than in 4w group in NC, DM and DMP groups, and showed similarities between NC and DMR group. The expressions of TNF-α and NF-κB were higher in DM 4w and 8w group than in NC and DMR 4w and 8w groups （all P〈0. 05） ,and was higher in 8w than in 4w group of NC, DM and DMR groups. The expression of NF-κB and TNF-α was positively correlated with renal cell apoptosis. Rapamycin treated DM group versus DM group showed a suppression of over-expression of renal TNF-α and NF-κB p65, and of renal cell apoptosis （all P〈0. 01）. Conclusions The NF-κB and TNF-α expression play an important role in development of diabetic nephropathy. Rapamycin has some renal protective effect on diabetes in rats, partly through down-regulating the NF-κB and TNF-α expression.