Regional Brain-derived Neurotrophic Factor mRNA Level Changes Following Trainsient Focal Brain Ischemia and Reperfusion in the Rat

Objective: To study the change of brain-derived neurotrophic factor mRNA (BDNFmRNA) in brain and the effect of BDNF on the neurons after focal cerebral ischemia nad reperfusion in the rats.Methods: The level of regional BDNFmRNA was measured in the rat brain using in situ hybridization.Result: 1.Under basal condition, The highest level of BDNFmRNA was found in the dentate gyrus and hippocampal CA3, Siginficantly lower levels of BDNFmRNA were detected in hippocampal CA1 and in necortes. 2. Following 1h or 3h of trainsient focal cerebral ischemia, There is a marded upregulation of BDNFmRNA expression in the bilateral brain. The lower level of BDNFmRNA in the serious ischemia group was found than that in the slight ischemia group, but also there was the lowest level of regional BDNFmRNA in the ischemic focus.3. After the reperfusion, BDNFmRNA expressions in cortex,hippocampus and ischemic focus increased to the maximum at 6h,12h,24h respectively and returned to contral level within 72h.Conclusion: The levels of regional BDNFmRNA showed here positively correlate at least partly with regional depperece in neuronal resistance to ischemia, which is consistent with the hypothesis of a neuroprotective role of BDNF.