Renoprotection Mechanism of Rehmannia Glutinosa Extract in Adriamycin Nephrotic Rats

Objective To evaluate the effect of rehmannia glutinosa extract on the pathogenesis of adriamycin-induced nephropathy and its mechanism.Methods Fifty male Sprague-Dawlay rats were randomly divided into 2 groups,including normal control group(n=10,group C),and model group(n=40).The rats model of nephropathy was established by tail vein injection of adriamycin 7.5 mg·kg-1.The normal control group was established by tail vein injection of physiological saline equally.After 2 weeks,if the urine protein was more than 30 mg in 24 hours,then the adriamycin nephrotic model was successful.The adriamycin nephrotic rats(35 rats)were divided randomly into model group of adriamycin-induced nephropathy(n=18,group M) and the group treated with rehmannia glutinosa extract(n=17,group D).Then group C and group M were intragastrically fed with physiological saline,while the rats in the group D were intragastrically fed with rehmannia glutinosa extract(10 g·kg-1).The total time was 8 weeks.The expressions of matrix metalloproteinases-2(MMP-2 )and tissue inhibitor of metalloproteinase-2(TIMP-2) in the cortex of the kidneys were examined by using immunohistochemistry and reverse transcription-polymerase chain reaction(RT-PCR) technique.Results On the 56th day,compared with group C,24 h urinary protein excretion,total cholesterol,serum creatinine and blood urea nitrogen increased significantly in group M,while albumin decreased significantly in group M;Meanwhile,compared with group M,after 8 weeks with rehmannia glutinosa extract,24 h urinary protein excretion,total cholesterol,serum creatinine and blood urea nitrogen decreased significantly in group D,but albumin increased significantly in group D.Compared with group M,protein expression levels of MMP-2 and TIMP-2 increased significantly in group D.Compared with group C,protein expression levels of MMP-2 and TIMP-2 descreased significantly in group D.Conclusions Rehmannia glutinosa extract offers a protective effect on adriamycin nephrotic rats.It possibly increase the expressions of MMP-2 and TIMP-2.The disproportion of MMP-2/TIMP-2,which result in the increased degradation of extracellular matrix may contribute to the development of glomerularsclerosis.