Effect of Taurine on iNOS-Mediated DNA Damage in Drug-Induced Renal Injury

Owing to an outstanding wide antitumor spectrum and excellent anti-tumor effect cisplatin has been used in chemotherapy for malignant tumor. However, cisplatin has strong side effects such as renal injury. Taurine has been found to protect against inflammatory tissue damage in a variety of experimental models. The aim of the present study was to investigate the effect of taurine against iNOS dependent DNA damage in cisplatin-induced renal injury in rats. With the help of a rat model of drug-induced kidney damage, we have assessed the nephrotoxic effects of different doses of cisplatin in the presence and absence of taurine. Immunohistochemical methods were used to examine the distribution of arginine, iNOS, citrulline and 8-nitroguanine in renal tissue. The expression levels of citrulline, iNOS, and 8-nitroguanine immunoreactivities were found to increase as a function of the dose of cisplatin used, and to decrease in the presence of taurine. The expression level of arginine immunoreactivity was reduced as a function of the dose of cisplatin used. On the other hand, iNOS, 8-nitroguanine and citrulline immunohistochemical staining showed an intense immunoreactivity in the renal tubule of cisplatin-treated animals; and arginine immunoreactivity was localized in the renal tubule of taurine-treated animals. We also confirmed the decrease of citrulline and iNOS expression in the renal tubule after taurine administration as well as the expression level of 8-nitroguanine, a nitrative stress marker in the same animals. The present results support the concept that taurine may have a protective role in the formation of cisplatin-related DNA lesions arising through iNOS-mediated nitrative stress.