Effect of prenatal cigarette smoke exposure on sevoflurane-induced respiratory suppression in neonatal rats and the protective role of hydrogen sulfide.

Prenatal cigarette smoke (CS) exposure causes numerous respiratory health problems in infants. This study aimed to investigate the effect of prenatal CS exposure on sevoflurane-induced respiratory suppression in neonatal rats and the protective role of H2 S. We found that at baseline, minute ventilation (V'E ), respiratory frequency (fR ), and tidal volume (VT ) were similar among tested groups, whereas sigh frequency (fS ) was lower in CS group than in the Control group. During 3% sevoflurane anesthesia, V'E was decreased, fR was slowed, VT was increased, and fS was reduced in all groups; however, the decline in fR and increase in VT was greater in CS group than in the Control group. During the recovery, fS remained lower in CS group. The above changes of respiratory response caused by prenatal CS exposure were alleviated by NaHS pretreatment (a donor of H2 S, 56 μmol/kg/d, intraperitoneal injection). These results indicated that prenatal CS exposure alters the breathing into a much slower and deeper manner in neonatal rats during sevoflurane anesthesia, and H2 S mitigates this respiratory change.