The expression and its significance of brain-derived neurotrophic factor in different hippocampal subfields after focal cerebral ischemia in rats

Objective To investigate the regulation of expression of brain derived neurotrophic factor (BDNF) in different hippocampus subfields and explore their effects on neuroplasticity of central nervous system after focal cerebral ischemia.Methods 40 healthy adult SD rats were divided randomly into ischemic group and sham-operated group. Unilateral cerebral ischemia was induced in rats by permanent occlusion of the distal middle cerebral artery. The expression of BDNF was examined by immunohistochemical techniques. Results (1) The expression of BDNF was different in hippocampus subfields after focal cerebral ischemia. It rose significantly in dentate gyrus, CA 3 and CA 4, compared with sham-operated group ( P 0.01), while it rose slightly in CA 1 and CA 2, with no significant difference ( P 0.05 ). (2) In the ischemic group, the expression of BDNF in hippocampus subfields increased at 7 days, significant increased at 14 days ( P 0.01), attained the peak at 21 days, and decreased in the later days. Conclusions Dentate gyrus, CA 3 and CA 4 showed well BDNF neuron protection mechanism after ischemic injury, played important role in regeneration and repair in central nervous system.