Cisplatin-induced cytotoxicity in BSO-exposed renal proximal tubular epithelial cells: Sex, age, and species

Background Cisplatin (CP)-induced kidney damage and effects of DL-buthionine-(S,R)-sulfoximine (BSO) on it are species- and age-different. It remains unclear whether CP-induced cytotoxicity in renal proximal tubular epithelial cells (RTEC), the main target cells of CP, is also species- and age-different; and whether CP-induced cytotoxicity varies with the difference in age and species, if any, is one of the questions. In the present study, the effects of BSO on CP-induced cytotoxicity in primary cultures of RTEC isolated from monkeys and different age and sex rats were studied. Methods. The RTEC were isolated from 3-week-old, 2-month-old, or 5-month-old rats, and 6-8 year-old monkeys. After subculturing, RTEC was inoculated into type I collagen-coated 96-well culture plates; after preincubation, 40 mu M BSO was added, 16 hours later, varying concentrations of CP were added. At that time, 3-(4,5dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assays were performed to test cell viability. Results. The concentrations of CP that inhibited 50% cell growth (IC50) Of RTEC from rats and monkeys were 1.11 and 3.03 mM at 8 hours, and 0.51 and 1.24 mM at 24 hours, respectively. The BSO made the IC(50)s of RTEC from rats and monkeys lower, down to 0.07 and 0.48 mM at 8 hours, and 0.02 and 0. 11 mM at 24 hours, respectively. The IC(50)s of RTEC from different sex and age rats were almost same. Conclusion. These results suggested that CP-induced cytotoxicity was concentration- and time-dependent, with species-dependent differences, rat RTEC were more susceptible to CP than monkey RTEC, rat RTEC were more dependent on glutathione (GSH) during the stress state were than monkey cells; CP-induced cytotoxicity was without sex- and age-dependent differences in rat RTEC.