OBJECTIVETo investigate the protective effect of ulinastatin (UTI) on HK-2 cells during paraquat (PQ)-induced injury and its underlying mechanisms.

METHODSRoutinely cultured HK-2 cells were divided into blank control group, PQ group, UTI+PQ group and UTI group. Cell viability was determined by CCK-8 assay. The concentration of PQ in HK-2 cells were measured by high performance liquid chromatography (HPLC). The production of total reactive oxygen species (ROS) were detected by fluorescence microscopy. The activities of superoxide dismutase activity (SOD) and the content of malondialdehyde (MDA) in HK-2 cells were observed by chemical colorimetry. The levels of tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6) were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTSPQ, even at a dose of 200 µM, could significant suppress the viability of HK-2 cells in a dose-dependent and time-dependent. UTI showed no significant inhibitory effect on the viability of HK-2 cells when given at a dose below 8 000 U/ml (P > 0.05). Compared with the PQ group, the UTI+PQ group had significantly increased the viability of HK-2 cells in a dose-dependent of UTI (P < 0.05). Compared with the PQ group on the same hour, the UTI+PQ group showed decreased in PQ concentration in HK-2 cells (P < 0.05 for all except 6 h). Compared with the blank control group, the PQ group had significantly decreased SOD activity and significantly increased ROS level and MDA content (P < 0.05). Compared with the PQ group, the UTI+PQ group had significantly increased SOD activity and significantly decreased ROS level and MDA content (P < 0.05). Compared with the blank control group, the PQ group had significantly increased IL-6 and TNF-α level (P < 0.05); Compared with the PQ group, the UTI+PQ group had significantly decreased IL-6 and TNF-α level (P < 0.05).

CONCLUSIONUTI significantly reduces the PQ-induced oxidative damage and inflammatory injury and its mechanism may be by reducing the accumulation of PQ in HK-2 cells.