人参皂苷Rh1对UUO大鼠肾纤维化的抑制作用

目的:观察并探讨人参皂苷Rh1(G-Rh1)对单侧输尿管梗阻(UUO)大鼠肾纤维化的抑制作用及其机制。方法:雄性SD大鼠40只,分为假手术组(sham组)、UUO组、G-Rh1低剂量组和G-Rh1高剂量组。手术后第2天开始,G-Rh1低剂量组和G-Rh1高剂量组分别每日灌胃50 mg/kg和100 mg/kg G-Rh1,连续2周。给药2周后,收集24 h尿测定尿蛋白,收集血清测定血清肌酐(SCr)和血尿素氮(BUN)。HE染色观察肾组织病理变化并对肾组织损伤程度评分。利用免疫组化和Western blot法观察肾组织中转化生长因子β_1(TGF-β_1)、α-平滑肌肌动蛋白(α-SMA)、Ⅰ型胶原蛋白和结缔组织生长因子(CTGF)的表达。结果:肾功能检测显示,各组大鼠24 h尿蛋白定量的差异无统计学显著性。UUO组BUN和SCr明显高于sham组(P 0. 05),G-Rh1低剂量组和G-Rh1高剂量组BUN和SCr明显低于UUO组(P 0. 05),同时G-Rh1高剂量组BUN和SCr低于G-Rh1低剂量组(P 0. 05)。光镜下观察,与sham组比较,UUO组病理改变显著,肾组织损伤明显,G-Rh1低剂量组和G-Rh1高剂量组与UUO组比较,肾损伤明显改善,G-Rh1高剂量组改善程度较G-Rh1低剂量组更显著。肾组织免疫组化显示,与sham组比较,UUO组肾小管及肾间质中TGF-β_1表达明显增多,G-Rh1低剂量组和G-Rh1高剂量组与UUO组比较,TGF-β_1表达明显下降,G-Rh1高剂量组较G-Rh1低剂量组降低更明显。Western blot检测显示,与sham组比较,UUO组Ⅰ型胶原蛋白、α-SMA和CTGF蛋白表达明显增多(P 0. 01),G-Rh1低剂量组和G-Rh1高剂量组与UUO组比较,Ⅰ型胶原蛋白、α-SMA表达明显下降(P 0. 05),G-Rh1高剂量组较G-Rh1低剂量组α-SMA和CTGF蛋白表达明显降低(P 0. 05),而Ⅰ型胶原蛋白表达无显著差异。结论:人参皂苷Rh1可缓解UUO大鼠肾组织纤维化,改善肾功能,其主要机制可能是抑制TGF-β_1信号通路中纤维化相关因子的表达。

Ginsenoside Rh1 attenuates unilateral ureteral obstruction-induced renal interstitial fibrosis in rats

AIM:To observe the effects of ginsenoside Rh1 (G-Rh1) on unilateral ureteral obstruction (UUO)-induced renal interstitial fibrosis and to investigate the underlying mechanisms. METHODS:Male Sprague-Dawley (SD) rats (n=40) were divided into the following 4 groups:UUO-operated group (UUO group), sham-operated group (sham group), UUO-operated plus a low dose (50 mg·kg^-1·d^-1) of G-Rh1 treatment (low G-Rh1 group) and UUO-operated plus a high dose (100 mg·kg^-1·d^-1) of G-Rh1 treatment group (high G-Rh1 group). The G-Rh1 treatment was carried out by gastric gavage from the next day after the UUO operation once a day for 2 weeks (14 d). Immediately after the final dose of G-Rh1, 24 h urine was collected for the urine protein test, and then the rats were euthanized. The blood was collected for the blood urea nitrogen (BUN) and serum creatinine (SCr) assays, and the kidney was removed for pathological and biochemical evaluations. RESULTS:The levels of 24 h urine protein did not show any significant diffe-rence among the groups, while significantly increased levels of BUN and SCr in UUO group were observed (P<0.05), which was prevented by the treatment with G-Rh1 at both doses in a dose-dependent manner. Pathological evaluation showed the renal tissue damage was obvious in UUO group, which was improved by the treatment with G-Rh1 at both doses. Immunohistochemcial analysis exhibited that UUO increased renal interstitial transforming growth factor-β₁ (TGF-β₁) expression, which was also inhibited by the treatment with G-Rh1 at both doses(P<0.05). Significantly increased protein expression of renal interstitial collagen type I, α-smooth muscle actin (α-SMA) and connective tissue growth factor (CTGF) in UUO group was detected, which was suppressed by the treatment with G-Rh1 at both doses. CONCLUSION:G-Rh1 improves UUO-induced renal dysfunction and attenuates interstitial fibrosis, which is mediated via modulation of TGF-β₁-related pro-fibrogenic signaling pathway.