RESUMEN
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.