Abstract

Background Today cadmium is considered as one of the main environmental factors in the development of kidney cancer. Objective The purpose of this study was to evaluate the effect of crocin on the expression of PAX2 and WT1 genes in renal tissue and serum levels of NGAL and cystatin C in cadmium-treated rats. Forty adult male Wistar rats were randomly divided into 4 groups, including the control group, crocin (20 mg/kg), cadmium (5 mg/kg), and crocin + cadmium. For 8 weeks, oral gavage was performed. Then, blood samples were collected and the kidney tissue was removed. PAX2 and WT1 genes expression were studied by real-time PCR and the levels of NGAL and cystatin C proteins were also evaluated in serum samples by the ELISA method. Results PAX2 expression in the cadmium-treated group was significantly higher than that of the other groups (P < 0.001), while the PAX2 expression in the crocin group was significantly lower than that of the other groups (P < 0.001). Expression of WT1 gene in cadmium-treated group was significantly increased compared to control (P < 0.001), crocin (P < 0.001) and crocin + cadmium (P = 0.008) groups. While the expression of WT1 in crocin group was significantly reduced compared to crocin + cadmium (P = 0.034) and cadmium groups (P < 0.001). The mean concentration of NGAL protein in the cadmium-treated group (1.6 +/- 0.35 ng/ml) was significantly (P < 0.001) higher in comparison to control (0.42 +/- 0.03 ng/ml), crocin (0.32 +/- 0.05 ng/ml) and crocin + cadmium groups (0.35 +/- 0.07 ng/ml). The mean serum cystine C concentration in the cadmium-treated group (1.34 +/- 0.38 mg/l) was significantly (P < 0.001) higher in comparison to control (0.52 +/- 0.18 mg/l), crocin (0.71 +/- 0.16 mg/l) and crocin + cadmium groups (0.93 +/- 0.2 mg/l). Conclusion Crocin reduces the expression of PAX2 and WT1 genes in renal tissue, and on the other hand, decreases the level of NGAL and cystine C proteins in the serum of rats, while cadmium increased the expression of these factors. Therefore, the results of our research indicate that crocin plays a protective role on the renal cell against the damage caused by cadmium.