Fertility and developmental neurotoxicity effects of inhaled hydrogen sulfide in Sprague–Dawley rats

Abstract In this study, we examined whether perinatal exposure by inhalation to hydrogen sulfide (H 2 S) had an adverse impact on pregnancy outcomes, offspring prenatal and postnatal development, or offspring behavior. Virgin male and female Sprague–Dawley rats (12 rats/sex/concentration) were exposed (0, 10, 30, or 80 ppm H 2 S; 6 h/day, 7 days/week) for 2 weeks prior to breeding. Exposures continued during a 2-week mating period (evidence of copulation = gestation day 0 = GD 0) and then from GD 0 through GD 19. Exposure of dams and their pups (eight rats/litter after culling) resumed between postnatal day (PND) 5 and 18. Adult male rats were exposed for 70 consecutive days. Offspring were evaluated using motor activity (PND 13, 17, 21, and 60 ± 2), passive avoidance (PND 22 ± 1 and 62 ± 3), functional observation battery (PND 60 ± 2), acoustic startle response (PND 21 and 62 ± 3), and neuropathology (PND 23 ± 2 and 61 ± 2). There were no deaths and no adverse physical signs observed in F 0 male or female rats during the study. A statistically significant decrease in feed consumption was observed in F 0 male rats from the 80-ppm H 2 S exposure group during the first week of exposure. There were no statistically significant effects on the reproductive performance of the F 0 rats as assessed by the number of females with live pups, litter size, average length of gestation, and the average number of implants per pregnant female. Exposure to H 2 S did not affect pup growth, development, or performance on any of the behavioral tests. The results of our study suggest that H 2 S is neither a reproductive toxicant nor a behavioral developmental neurotoxicant in the rat at occupationally relevant exposure concentrations (⩽10 ppm).