ABSTRACT
Objective To explore the role of tissue inhibitor of metalloproteinase-1(TIMP-1) during renal senescence by using human TIMP-1 transgenic mice.Methods Renal histological changes of wild type mice and transgenic mice at the age of 3,12,24 months were observed by periodic acid-schiff(PAS)staining of paraffin sections.The numbers of F4/80 positive cells were detected by immunofluoreseence.The protein expressions of TIMP-1,TIMP-2,matrix metalloproteinase(MMP)-9,MMP-2,intercellular adhesion molecule-1(ICAM-1),transforming growth factor?1(TGF-?1),collagenⅢand collagenⅣwere detected by Western blot.The activities of gelatinases and TIMP-1 were examined by gelatin zymography and reverse zymography respectively.Results Focal renal fibrosis was found in two genotypes with aging.At the age of 24 months,compared with wild type,in kidneys of transgenic type,the expressions and activities of gelatinases were dowregulated (MMP-2:2.08?0.20 vs.3.39?0.43;MMP-9:4.02?0.82 vs.6.72?1.40,all P＜0.05);the expressions of collagenⅢ,collagenⅣ,ICAM-1,and TGF-?1 were upragulated(0.72+0.11 vs.0.57?0.09;0.84?0.13 vs.0.6?0.11,0.72?0.12 vs.0.53?0.07; 0.69?0.12 vs.0.45?0.09,all P＜0.05),and the numbers of F4/80 positive cells were increased (18.8?4.4 vs.12.7?3.6,P＜0.05)with the upregulated expression and activity of TIMP-1(1.10?0.18 vs.0.62?0.09;50.75?7.25 vs.20.64?3.50,P＜0.05).Conclusions TIMP-1 could promote age-related renal fibrosis through enhancing inflammation reaction by ICAM-1 upregulation.