BACKGROUND: Some researches demonstrate that exogenous bone morphogenetic protein 7 (BMP-7) can protect ischemic cerebral nerve tissue and promote recovery of motor energy function; however, there is lack of direct evidences of endogenous BMP-7 effect.OBJECTIVE: To observe the expression of endogenous BMP-7 in nerve tissue with ischemic-hypoxic injury and investigate the possible effects on damaged nerve tissue.DESIGN: Observational contrast animal study.SETTING: Department of Anatomy and Histoembryology, Peking University Health Science Center.MATERIALS: The experiment was carried out in the Nerve Researching Laboratory of Anatomy Department, Peking University Health Science Center from October 2006 to March 2007. A total of 25 adult male SD rats weighing 250 - 300 g and several newborn SD rats were selected from Experimental Animal Center, Peking University Health Science Center. Rabbit-anti-BMP-7 polyclonal antibody was provided by Wuhan Boster Company.METHODS: ① Adult rats were randomly divided into ischemia group (n =10), sham operation group (n =10) and normal group (n =5). Right external-internal carotid artery occlusion was used to infarct middle cerebral artery of adult rats in the ischemia group so as to copy focal cerebral infarction models. Line cork was inserted in crotch of internal and external carotid artery of adult rats in the sham operation group, while adult rats in the normal group were not given any treatments. ② Cerebral cortex of newborn rats was separated to obtain cell suspension. Cells which were cultured for 10 days were divided into control group and hypoxia/reoxygenation group. And then, cells in the hypoxia/reoxygenation group were cultured in hypoxic incubator for 4 hours and given reoxygenation for 24 hours.MAIN OUTCOME MEASURES: Immunohistochemical method was used to measure expression of BMP-7 in cerebral cortex at 24 hours after ischemia/reperfusion culture and in primary hypoxic culture.RESULTS: ① At 24 hours after cerebral ischemia, expression of BMP-7 in cerebral cortex on ischemic side was stronger than that on non-ischemic side in adult rats; meanwhile, numbers of cell expression were increased. However, expression of BMP-7 was not detected in bilateral cerebral cortex of adult rats in both control group and sham operation group. ② After hypoxia of cerebral cortex in primary culture, positive products of BMP-7 were observed in plasma of neuron, but expression of BMP-7 was not found in normal cerebral cortex.CONCLUSION: Endogenous BMP-7 has protective effects on nerve tissue induced by ischemic-hypoxic injury.