Relationship between oxidative protein damage and serum matrix metalloproteinase-2 in diabetic nephropathy

Objective Serum indicators of oxidative protein damage (OPD) were analyzed to explore the effect on renal MMP/TIMP system of OPD in diabetic nephropathy. Methods AOPP levels and PCO levels were measured by modified Witko-Sarsat's method and 2, 4-dinitrophenylhydrazine spectrophotometric method, expression of serum MMP-2 were determined by ELISA, and MMP-2 activity were detected by zymography . Results AOPP levels of group DN1, group DN2 were higher than those of group DM(78.23±19.30 vs 61.25±12.13,101.59±30.22 vs 61.25±12.13,F＝41.988,P＜0.01). PCO levels of group DN1 and group DN2 were higher than those of group DM (0.84±0.03 vs 0.66±0.02,1.05±0.05 vs 0.66±0.02,F＝205.763,P＜0.01). Pearson correlation analysis indicated AOPP and PCO were positively correlated with the expression (r＝0.460,0.480,P＜0.05) and activity (r＝0.385,0.560,P＜0.05) of serum MMP-2. Multiple stepwise regression analysis showed that AOPP and PCO were major influential factors of serum MMP-2 expression (P＜0.05,P＜0.01) and activity(P＜0.01,P＜0.05). Conclusions OPD might be involved in the imbalance of renal matrix metabolism, which was correlated with the development of diabetic nephropathy. Key words: Diabetic nephropathies/ME; DNA damage; Matrix metalloproteinase 2/ME; Protein hydrolysates/ME