Influence of Environment Stimulation on Learning and Memory Ability and Hippocampal Pathology of Neonatal Rats with Hypoxic-Ischemic Brain Damage

Objective To observe the influence of environment stimulation on learning and memory ability and hippocampal pathology of neonatal rats with hypoxic-ischemic brain damage (HIBD).Methods The models of HIBD SD rats were established by the method of Rice, and were divided randomly into three groups: enriched environment stimulation group (EE), impoverished environment stimulation group (IE), and standard environment stimulation group (SE). The sham-operation rats were served as control group. Different environment stimulation was administrated to the rats since day 1 after HIBD.On the day 28,Morris water maze was used to evaluate the learning and memory ability. HE staining and nissl stain were employed to observe the pathological change and the number of neurons in hippocampus of rats.Results The learning and memory ability of EE group was significantly higher than that of SE group (P0.01) and IE group (P0.001), and there was no significant difference compared EE group with Sham group (P0.05), and the ability of SE group was higher than that of IE group ( P0.01 ). The results of HE stain displayed the pathology in left-sided hippocampus of Sham group was normal, and that of EE group was minimal abnormal, while the pathology of SE group and IE group were obviously abnormal.The nissl staining showed that the number of left-sided hippocampal neurons was no significant difference compared EE group with Sham group (P0.05). The number of SE group was lower than that of Sham group (P0.01), and was significantly more than that of IE group (P0.05).Conclusion The study suggests that EE is good for recovery from brain damage and protected brain of rats with HIBD,but IE is not good for it.