RESUMO
PURPOSE: Perinatal hypoxic-ischemic (HI) brain injury remains a common cause of chronic handicapping conditions of cerebral palsy, mental retardation, learning disability, and epilepsy. HI brain injury induces cell death via either necrosis or apoptosis. Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family. It plays key roles in survival, differentiation, and maintenance of neurons. This study was to investigate the neuroprotective effects of BDNF via the mechanisms of anti-apoptosis in HI brain injury by using cortical astrocyte and neuronal cell culture. METHODS: Cortical astrocytes culture of 1-day-old Sprague-Dawley (SD) rat pups and embryonic cortical neuronal cell culture of SD rats at 14-day gestation were done. The Normoxia group was prepared in 5% CO2 incubators and the Hypoxia group and Hypoxia+BDNF group (after treatment with BDNF for 24 hours) were placed in 1% O2 incubators (94% N2, 5% CO2) for 6 or 18 hours. The expression of Bcl-2 and Bax were assessed by real-time PCR and western blot. The caspase-3 activation was evaluated by caspase activity assay kit. RESULTS: In astrocyte and neuronal cell, the expressions of Bcl-2 in the hypoxia groups were reduced compared to the normoxia groups, whereas, those in the Hypoxia+BDNF groups were increased compared to the hypoxia groups. However, the expressions of Bax and caspase-3 and the ratio of Bax/Bcl-2 were revealed reversely. In astrocyte, Hypoxia group for 6 hours was not significantly altered in Bcl-2, Bax expressions. CONCLUSION: BDNF neuroprotective effects on HI brain injury in neonatal rats may occur via anti-apoptotic mechanism.