RESUMEN
Objective To test the effects of restuscitation with air or oxygen on the blood gas and cerebral superoxide dismutase (SOD) concentration in neonatal rats with experimental intrauterine asphyxia. Method Seventy-seven neonatal rats were randomly (random number) divided into three experimental groups: sham operation group (SHAM), air resuscitation group (AR), and oxygen resuscitation group (OR). In groups AR and OR, animal models of intrauterine asphyxia were established and then resuscitated with air (AR) or oxygen (OR) for 30min. Comparison was made between groups including the mortality 0 hour after resuscitation, and the levels of blood gas and cerebral SOD concentrations 0 h, 6 h and 24 h after resuscitation. Results Mortality of neonatal rats in SHAM group, AR group and OR group were 0 (0/24), 0 (0/26) and 3.7% (1/27), respectively (P ＞0.05). The average levels of blood PaO2 in OR group and AR group 0 h after resuscitation were (69.2 ± 8.2)mmHg and (55.5±10.3) mmHg,respectively (P=0.004). Blood pH and PaCO2 and BE levels in OR group 0 h after resuscitation were not significantly different from those in AR group (P＞0.05). Blood pH, PO2, PCO2and BE levels in OR group were also not significantly different from those in AR group 6 h and 24 hours after resuscitation. The average concentrations of cerebral SOD in OR group 0 h and 6 hours after resucitation were (38.3±9.8) U/mgprot and (8.6±3.6) U/mgprot, and those in AR group were (53.8± 10.6) U/mgprot and (13.0±4.6) U/mgprot, respectively (P = 0.003, 0.04). The cerebral SOD concentration in OR group 24 hours after resuscitation was not significantly different from that in AR group (P＞0.05). The cerebral SOD concentrations in SHAM group 0 h,6 h and 24 hours after resuscitation were much higher than those in OR group and AR group (P＜0.05). Conclusions Resuscitation with air is as good as pure oxygen in neonatal resuscitation, in respect of early mortality and improvement of acidosis in neonatal rats after intrauterine asphyxia. Resuscitation with air will generate less radical oxygen species than pure oxygen in neonatal rats after intrauterine asphyxia.