[Effects of environmental enrichment on the repair and proliferation of neurons in neonatal rats with hypoxic-ischemic brain damage].

OBJECTIVE

To study the effects of environmental enrichment on neuron proliferation, learning and memory ability and motor ability in neonatal rats with hypoxic-ischemic brain damage (HIBD).

METHODS

One hundred and eight 7-day-old Sprague-Dawley rats were randomly divided into three groups: sham operation (CON group), HIBD and intervention group. HIBD model was prepared according to the classic Rice-Vannucci method. Environmental enrichment was administered for the rats in the intervention group after HIBD inducement. Behavioral tests (Water maze test, Suspension test and Slope test) were performed and the number of neural cells in the left hippocampus was examined 7, 14 and 28 days after intervention.

RESULTS

The pyramid cells in the hippocampus CA1 area in the HIBD group were significantly less than in the CON group at 7, 14 and 28 days (P<0.05). The number of pyramid cells in the hippocampus CA1 area in the intervention group was significantly higher than in the HIBD group (P<0.01) at 7, 14 and 28 days. The hidden platform escape latency period (EL) in the Water maze test was significantly more prolonged and the cross-platform number within 2 minutes was significantly less in the HIBD and the intervention groups than in the CON group at all observed time points (P<0.01). The EL was significantly shorter and the cross-platform number within 2 minutes was significantly higher in the intervention group than in the HIBD group at all observed time points (P<0.01). The maintain time and score in the Suspension test were significantly lower and the time in the Slope test was significantly more prolonged in the HIBD and intervention groups than in the CON group at 7, 14 and 28 days (P<0.01). An increased maintain time and score and a decreased time in the Slope test were found in the intervention group compared with the HIBD group at 14 and 28 days (P<0.01).

CONCLUSIONS

Environmental enrichment can improve motor function, learning and memory ability, and promote the repair and proliferation of neurons in neonatal rats with HIBD.