RESUMO
Objective To establish an appropriate preterm hypoxic-ischemic brain injury animal model. Methods A total of 32 pregnant New Zealand white rabbits at gestational day 25 were selected. The uterine blood supply in pregnant rabbits was blocked for 30, 35, 37, 40 minutes respectively, while in the control group it was not blocked. Then the pregnant rabbits were subjected to cesarean section 24 hours (at embryonic day 26, A group) or 5 days (at embryonic day 30, B group) after the experimental procedure. The general conditions of the newborn rabbits were recorded. The degree of neurobehavioral impairment in newborn rabbits was evaluated. The histological changes of brain tissue were observed. Results In A group, all newborn rabbits survived with ischemia for 30 minutes, while the stillbirth rates increased from 31.0% to 100% with ischemia from 35 to 40 minutes. In survived nowborn rabbits, the brain water content and the number of apoptotic brain cells were increased with prolonged ischemia. All these differences were statistically significant (all P<0.05). In B group, the stillbirth rates increased to 50.0% and 65.7% respectively with ischemia for 35 or 37 minutes. The birth weight of survived newborn rabbits were significantly lower than that in the control group. The neurobehavioral test scores were significantly lower in ischemic groups than that in the control group. All these differences were statistically significant (all P<0.05). The pathological examination of brain tissue found that the white matter damage in B group was more obvious than that in A group. Conclusions Continuous blockage of uterine blood supply in pregnant rabbits at gestational day 25 causes stillbirth, neurobehavioral damages and white matter injury as well as fetal rabbit intrauterine growth restriction, which can be used for the preparation of preterm hypoxic-ischemic brain injury animal model.