Objective:To study the protective effect of BDNF to newborn rats with hypoxic-ischemic brain damage before the modeling.Methods:Two hundred and fifty-six 7-day-old Wistar rats were randomly divided into four groups: sham operation group(n=64

A);model group(n=64

B);model pre-treated group(n=64

C);model post-treated group(n=64

D)

every group are further divided into 1、3、5、 7 d four time points(n=8).The expression of Trk-B and p75 in Hippocampus was examined with immunohisto chemical staining and real-time PCR.Results:Trk-B and p75 levels in model pre-treated group and model post-treated group

had significant differences compaed with model group and sham operation group

P<0.05.Conclusion:BDNF has a protective effect to the brain injury caused by HIBD. Enhancing the expression of Trk-B levels and reduce the expression level of p75 may play a role.