金钗石斛多糖对多柔比星肾病大鼠肾纤维化及PI3K/Akt/HIF-1α通路的影响

Effects of Dendrobium Nobile Polysaccharide on Renal Fibrosis and PI3K/Akt/HIF-1α Pathway in Adriamycin Nephropathy Rats

目的:探讨金钗石斛多糖对多柔比星肾病大鼠肾组织纤维化及磷脂酰肌醇3激酶/丝氪酸-苏氪酸蛋白激酶/缺氧诱导因子-1α(PI3K/Akt/HIF-1α)信号通路的影响,并分析其可能的作用机制。方法:将48只SD大鼠随机分为正常对照组、模型组、阳性对照组(依那普利,4 g·kg-1·d-1)、金钗石斛多糖低(5 g·kg-1·d-1)、中(10 g·kg-1·d-1)、高(20 g·kg-1·d-1)剂量组,每组各8只。除正常对照组外,其余各组大鼠制备多柔比星肾病大鼠模型。造模成功后灌胃给药,1次/d,连续给药4周,正常对照组和模型组给予等量生理盐水。采用Masson染色观察多柔比星肾病大鼠肾脏纤维化程度;检测各组大鼠肾功能指标;采用实时荧光定量聚合酶链反应(qRT-PCR)检测肾组织中平滑肌肌动蛋白(α-SMA)、纤维连接蛋白(FN)、结缔组织生长因子(CTGF)mRNA表达水平;Western blot法检测α-SMA、FN、CTGF、PI3K及磷酸化PI3K(p-PI3K)、Akt及磷酸化Akt(p-Akt)、HIF-1α蛋白表达。结果:与正常对照组相比,模型组大鼠血清肌酐(Scr)、尿素氮(BUN)水平、24 h尿蛋白含量、胶原纤维阳性区占观察视野面积比、肾组织中α-SMA、FN、CTGF及p-PI3K、p-Akt、HIF-1α表达水平均显著升高(P<0.05);与模型组相比,阳性对照组与金钗石斛多糖不同剂量组大鼠Scr、BUN水平、24 h尿蛋白含量、胶原纤维阳性区占观察视野面积比、肾组织中α-SMA、FN、CTGF及p-PI3K、p-Akt、HIF-1α表达水平均显著降低(P<0.05),且金钗石斛多糖高剂量组与阳性对照组均显著低于金钗石斛多糖低、中剂量组(P<0.05),阳性对照组与高剂量组比较差异无统计学意义(P>0.05)。各组PI3K、Akt蛋白表达差异无统计学意义(P>0.05)。结论:金钗石斛多糖可改善多柔比星肾病大鼠肾功能并减缓肾纤维化,其机制可能与抑制PI3K/Akt/HIF-1α信号通路有关。

Objective: To investigate the effects of dendrobium nobile polysaccharide on renal fibrosis and phosphatidylinositol 3 kinase/sericin-threonine protein kinase/hypoxia inducible factor-1α( PI3 K/Akt/HIF-1α) signaling pathway in adriamycin nephropathy rats,and analyze its possible mechanism. Methods: Totally 48 SD rats were randomly divided into the normal control group,the model group,the positive control group( enalapril,4 g·kg-1·d-1),dendrobium nobile polysaccharide low(5 g·kg-1·d-1),medium( 10 g·kg-1·d-1) and high( 20 g·kg-1·d-1) dose groups with 8 rats in each group. Except the normal control group,the other groups were used to make adriamycin nephropathy rat models. After the successful model establishment,the rats were given corresponding drug orally once a day for 4 weeks,and the normal control group and the model group were given the same amount of saline.Masson staining was used to observe the degree of renal fibrosis in rats with adriamycin nephropathy;the indices of renal function in each group were detected;the mRNA expressions of smooth muscle actin(α-SMA),fibronectin( FN),connective tissue growth factor( CTGF) were detected by real-time fluorescence quantitative polymerase chain reaction( qRT-PCR);the protein expressions of α-SMA,FN,CTGF,PI3 K,phosphorylated PI3 K( p-PI3 K),Akt,phosphorylated Akt( p-Akt) and HIF-1α were detected by Western blot. Results: Compared with those in the normal control group,the levels of serum creatinine( Scr) and urea nitrogen( BUN),24-hour urinary protein content,the ratio of collagen fibers positive area to visual field,and the expressions of α-SMA,FN,CTGF,pPI3 K,p-Akt and HIF-1α in renal tissues of rats in the model group were significantly increased( P < 0. 05). Compared with those in the model group,Scr and BUN levels,24-hour urinary protein content,the ratio of collagen fibers positive area to visual field,and the expressions of α-SMA,FN,CTGF and p-PI3 K,p-Akt,HIF-1 in kidney tissues of rats in the positive control group and dendrobium nobile polysaccharide groups were significantly decreased( P < 0. 05),and those in the high dose group and the positive control group were significantly lower than those in the low and middle dose groups( P < 0. 05),and there were no significant differences between the positive control group and the high dose group( P > 0. 05). There were no significant differences in the expressions of PI3 K and Akt protein in each group( P > 0. 05). Conclusion: Dendrobium nobile polysaccharide can improve renal function and slow down renal fibrosis in rats with adriamycin nephropathy,and its mechanism may be related to the inhibition of PI3 K/Akt/HIF-1α signaling pathway.