OBJECTIVETo assess the value of determination of urine kidney injury molecule-1 (KIM-1) protein content in the early diagnosis of radiocontrast-induced nephropathy (RCIN) in rats.

METHODSSeventy-two adult male SD rats were randomly divided into groups A, B, C (n=8) and D group (which was subdivided into 2, 6, 12, 24, 48 h and 7 days groups, n=8). Group A was subject to injections via the tail vein of PBS and normal saline (NS), group B received injections of PBS, NS, and contrast medium (CM), group C with indomethacin (INDO), nitric oxide synthase inhibitor (L-NAME), and NS, and group D with INDO, L-NAME and CM. Each injection was given at the interval of 15 min.

RESULTSIn group D, serum creatinine (Scr) and urea nitrogen (BUN) were significantly increased at 6 h after the injections (P<0.001), peaked at 24 h and recovered normal levels at 48 h. Histological examination revealed significant pathological changes in the kidneys at 6 h, showing diffuse tubulointerstitial hyperemia and hemorrhage, marked tubular necrosis and tubular structure destruction; at 12 h, significant tubular necrosis was still present with tubular structure destruction, but the tubulointerstitial hemorrhage was alleviated; at 24 h, tubular regeneration occurred in the renal medulla, but even till 7 days the tubular structures failed to show full recovery. In group D, urine KIM-1 level began to increase at 2 h, reached the peak level at 24 h, and lasted till 7 days (P<0.001); urine N-acetly-β-D-glucosaminidase (NAG) value began to increase at 6 h and became normal at 48 h. Urine MMP-9 level underwent no significant changes in group D over the time points of observation.

CONCLUSIONThe results show that urinary KIM-1 levels can be used as an indicator for early diagnosis of RCIN.