褐藻多糖硫酸酯抑制大鼠肾间质纤维化的实验研究

Mechanism of inhibition of renal tubular epithelial-mesenchymal transition in adenine-induced chronic renal failure rats treated with fucoidan

目的观察褐藻多糖硫酸酯(FPS)对慢性肾衰竭大鼠肾间质纤维化及肾小管上皮-间充质细胞转化(EMT)的作用,并探讨该作用与肾组织转化生长因子-β1(TGF-β1)、单核细胞趋化蛋白1(MCP-1)、血小板反应蛋白1(TSP-1)和血管内皮生长因子(VEGF)表达变化的关系。方法将6周龄Wistar雄性大鼠随机分为3组,即正常对照组(n=15),进食普通饲料;CRF模型组(n=24),进食含0.75%腺嘌呤的饲料;CRF+FPS组(n=24),进食含0.75%腺嘌呤饲料的同时,每天给予FPS200mg/kg灌胃。分别于第2、4、6周末处死大鼠,留取肾组织。采用免疫组化方法检测肾组织肌动蛋白α(α-SMA)的表达,分别采用免疫组化方法和逆转录酶PCR法(RT-PCR)检测肾组织TGF-β1、MCP-1、TSP-1及VEGF的蛋白和mRNA表达情况。结果第2、4、6周时CRF+FPS组大鼠肾组织α-SMA蛋白表达均明显低于同期CRF模型组(P<0.05)。CRF+FPS组大鼠肾组织第2、4周时TGF-β1、MCP-1、TSP-1表达明显低于同期CRF模型组(P<0.05),而第2周时TGF-β1、MCP-1、TSP-1的mRNA表达明显低于同期CRF模型组(P<0.05),第4周时MCP-1的mRNA表达明显低于同期CRF模型组(P<0.05)。CRF+FPS组第2、4周时肾组织VEGF蛋白和mRNA表达明显高于同期CRF模型组(P<0.05)。结论FPS对慢性肾衰竭大鼠肾小管上皮-间充质细胞转化具有抑制作用,该作用与肾组织TGF-β1、MCP-1及TSP-1的表达下调和VEGF表达上调有关,这可能部分解释FPS的肾保护作用机制。

Objective To observe the effect of fucoidan on renal tubular epithelialmesenchymal transition （EMT） in adenine -induced chronic renal failure in rats, and examine the relationship between EMT and expressions of transforming growth factor β1 （TGF-β1）, monocyte chemoattractant protein-1 （MCP-1）, vascular endothelial growth factor （VEGF） and thrombospondin-1 （TSP-1） in renal tissue. Methods Male Wistar rats were divided into three groups： ① normal group（n=15）, ②CRF group（n=24）, ③CRF＋ FPS group （n=24）. CRF rats had free access to diet containing 0.75% adenine. CRF ＋FPS rats had access to diet containing 0.75% adenine, as well as FPS 200 mg/（kg·d）, intragastric administration. All the rats were sacrificed at the end of week 2, 4, 6. Expressions of α-smooth muscle actin （α-SMA）, MCP-1, TGF-β1, VEGF and TSP-1 were detected by immunohistological and/or RT-PCR. Results The expressions of α-SMA, MCP-1, TGF-β1 and TSP-1 in renal tissue were significantly lower in CRF＋FPS group compared with the CRF group, respectively. Meanwhile VEGF expression in renal tissue was significantly higher in CRF＋FPS group than in the CRF rats. Conclusions The inhibitory effect of fucoidan on EMT is probably related to down-regulated expressions of TGFβ1, MCP-1 and TSP-1, and up-regulated expression of VEGF. The exact mechanism needs to be studied further.