OBJECTIVETo investigate the neuroprotective effect of leptin by observing its effect on spatial memory of rats with white matter damage in developing brain.

METHODSA total of 80 neonatal rats were randomly divided into 3 groups: sham-operation (n=27), model (n=27) and leptin intervention (n=27). The rats in the model and leptin intervention groups were used to prepare a model of white matter damage in developing brain, and the rats in the leptin intervention group were given leptin (100 μg/kg) diluted with normal saline immediately after modelling for 4 consecutive days. The survival rate of the rats was observed and the change in body weight was monitored. When the rats reached the age of 21 days, the Morris water maze test was used to evaluate spatial memory.

RESULTSThere was no significant difference in the survival rate of rats between the three groups (P>0.05). Within 10 days after birth, the leptin intervention group had similar body weight as the sham-operation group and significantly lower body weight than the model group (P<0.05); more than 10 days after birth, the leptin intervention group had rapid growth with higher body weight than the model and sham-operation groups (P>0.05). The results of place navigation showed that from the second day of experiment, there was a significant difference in the latency period between the three groups (P<0.05); from the fourth day of experiment, the leptin intervention group had a similar latency period as the sham-operation and a significantly shorter latency period than the model group (P<0.05). The results of space search experiment showed that compared with the sham-operation group, the model group had a significant reduction in the number of platform crossings and a significantly longer latency period (P<0.05); compared with the model group, the leptin intervention group had a significantly increased number of platform crossings and a significantly shortened latency period (P<0.05), while there was no significant difference between the leptin intervention and sham-operation groups.

CONCLUSIONSLeptin can alleviate spatial memory impairment of rats with white matter damage in developing brain. It thus exerts a neuroprotective effect, and is worthy of further research.