Lack of protective action of cysteine against the fetotoxic effect of monocrotaline

Monocrotaline (MCT), a pyrrolizidine alkaloid present in Crotalaria species , has hepatotoxic. nephrotoxic, pneumotoxic and fetotoxic effects. However, the toxic effects of exposure to MCT in adult rats can be prevented by cys teine. Thus, the present study was conducted to evaluate the possible preve ntion by cysteine of the toxic effects of MCT on pregnant rats. Thirty-six pregnant rats were used. The females in the experimental groups were fed ra tion containing 0.02% MCT, 0.02% MCT + 1% cysteine, or 1% cysteine from day 6 to day 21 of pregnancy; the control group was fed only common ration for the same period of time. All rats were killed on day 21 of pregnancy and t heir blood was collected for determination of liver and kidney function. Ge neral toxicity to pregnant darns was assessed. Fetuses were removed by caes arian section and embryofetotoxic parameters were examined. Results showed impaired body weight gain in rats fed MCT, with or without cysteine supplem entation. Plasma levels of AST, ALT, LDH, GGT, urea and creatinine were inc reased in MCT animals compared to controls. The pathology study revealed le sions only in darns from the MCT group. The weights of the placentas and fe tuses of the MCT and MCT + cysteine groups were Significantly lower than th ose of the control group. Thus, the present data suggests some protective a ction of 1% of cysteine in ration against the toxic effects of MCT on the d ams but not on the litter. (C) 2001 Elsevier Science Ltd. All rights reserv ed.