性别对新生缺氧缺血性脑损伤大鼠学习记忆功能及脑组织损伤的影响

The effect of sex differences on the ability of learning and memory and brain tissue damage of newborn rats with hypoxic-ischemic brain damage

目的 探讨不同性别新生大鼠缺氧缺血性脑损伤（hypoxic ischemic brain damage,HIBD）后学习记忆功能及脑组织损伤的改变.方法 新生7d龄SD大鼠60只,采用随机数表法分为雄性对照组、雌性对照组、雄性HIBD组、雌性HIBD组,每组15只.HIBD模型采用Rice-Vannucci方法,HIBD后28 d应用Morris水迷宫实验来评估四组大鼠空间学习记忆功能;应用头颅MRI、电子显微镜评估脑组织损伤范围及损伤部位神经元突触超微结构的改变.结果 雄性对照组大鼠各项检测结果与雌性对照组比较无显著性差异,均P＞0.05;雄性HIBD组及雌性HIBD组大鼠与各自对照组比较,逃避潜伏期[（39.38± 11.40）svs（14.86±4.42）s、（30.14±7.18）s vs （18.41±5.03）s]延长,游泳距离[（15.31±1.77） cm vs （3.68±-1.50） cm、（13.18±1.79） cm vs （4.61±1.61） cm]延长,透射电镜观察突触间隙[（23.18±1.36） nm vs （19.24±1.51） nm、（21.40±1.71） nm vs （19.87±0.94） nm]增宽,均P＜0.05,且雄性HIBD组较雌性HIBD组改变更加明显,差异具有统计学意义（P＜0.05）;雄性HIBD组大鼠头颅MRI上脑损伤容量较雌性HIBD组大鼠明显增大,差异具有统计学意义（P＜0.05）.结论 雌性大鼠对HIBD的耐受能力和/或恢复能力可能较雄性大鼠强.

Objective To explore the effect of sex difference on learning and memory function and the brain tissue damage of neonatal SD rats with hypoxic-ischemic brain damage.Methods Sixty,7-day-old neonatal Sprague-Dawley rats,were divided into randomly：male control group （M group,n=15）,female control group （F group,n=15）,male hypoxic-ischemic brain damage group （MHIBD group,n=15） and female hypoxic-ischemic brain damage group （FHIBD group,n=15）.A modified newborn rat model that had a combined hypoxic-ischemic brain damage as described by Rice-Vannucci was used.The Morris water maze was used to evaluate the ability of learning and memory.The brain MRI and transmission electron microscope（TEM） was used to evaluate the scope of brain tissue damage and the change of the synaptic ultrastructure.Results There were no differences in swimming distance,escape latency,synaptic cleft and damage brain volume between M group and F group（P〉0.05）.Compare with M group and F group,MHIBD group and FHIBD group showed significant brain injury,longer escape latency （（39.38±11.40） s vs （14.86±4.42） s,（30.14±7.18）s vs （18.41±5.03） s）,longer swimming distance （（15.31± 1.77） cm vs （3.68±1.50） cm,（13.18±1.79） cm vs （4.61±1.61） cm）,and TEM showed the synaptic cleft was widened （（23.18± 1.36） nm vs （19.24± 1.51） nm,（21.40± 1.71） nm vs （19.87±0.94） nm）,P〈0.05）.MHIBD group was more seriously compromised than the FHIBD group（P〈0.05）.The brain MRI showed the damage brain volume of MHIBD group were significantly larger than FHIBD group（P〈0.05）.Conclusion After bypoxic ischemic brain damage,the tolerance of brain damage and / or post-injury recovery capabilities of female rats are stronger than males.