Protective effect of hyperbaric oxygen at the end of pregnancy on neurons of fetal rats with fetal growth restriction

Objective To investigate the protective effect of hyperbaric oxygen (HBO) and normobaric hyperoxia (NBH) on neurons of fetal rats with fetal growth restriction (FGR).Methods Forty 12-d-pregnant SD rats were chosen in our study,these rats were equally randomized into 5 groups (n=8),respectively,as follows:(1) sham-operated group,not performed ligation of the uterine vessels; (2)FGR group; (3) HBO treatment group (FGR+HBO),given HBO with 0.2 MPa pressure after FGR models were made; (4) NBH treatment group (FGR+NBH):given NBH with concentration of 900 mL/L after FGR models were made; (5) low-concentration oxygen treatment group (FGR+LCO):given HBO with concentration of 300 mL/L after FGR models were made; treatments were given to these rats 80 min daily for a consecutive 7 d.Cesarean section was delivered when these rats were on the 21st d of pregnancy,the newborn rats (randomly taken 10 rats) were performed histopathological examination.Results As compared with that in the sham-operated group,the density of nerve cells and Nissl-positive cells in the cerebral cortex and hippocampus in 0-,7-and 14-d-neonatal rats of the FGR group were significantly reduced,and the number of apoptotic cells was significantly increased(P＜0.05).As compared with that in the FGR group,the density of nerve cells and Nissl-positive cells in the cerebral cortex and hippocampus in 0-,7-and 14-d-neonatal rats of the HBO treatment group and NBH treatment group was significantly increased,and the number of apoptotic cells was significantly reduced (P＜0.05).The above indicators between HBO treatment group and NBH treatment group,and between LCO treatment group and FGR group showed no statistical differences (P＞0.05).Conclusion High concentrations of oxygen at the end of pregnancy has a protective effect on nerve cells in the cerebral cortex and hippocampus of fetal rats. Key words: Fetal growth restriction; Hyperbaric oxygen; Normobaric hyperoxia; Cerebral cortex; Hippocampus