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

In this study, we examined whether perinatal exposure by inhalation to hydrogen sulfide (HPS) 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 H2S; 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 H2S 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 H2S did not affect pup growth, development, or performance on any of the behavioral tests. The results of our study suggest that H2S is neither a reproductive toxicant nor a behavioral developmental neurotoxicant in the rat at occupationally relevant exposure concentrations (less than or equal to 10 ppm). (C) 1999 Elsevier Science Inc. All rights reserved.