The cell-specific upregulation of bone morphogenetic protein-10 (BMP-10) in a model of rat cortical brain injury

Abstract

Previous studies have suggested that bone morphogenetic protein-6 (BMP-6) has a pronounced upregulation in rat brains subjected to traumatic brain injury. Bone morphogenetic protein-10 (BMP-10) is a newly identified cardiac-specific peptide growth factor that belongs to the TGF-β superfamily. To elucidate the dynamic expression changes and cellular localization of BMP-10 during traumatic brain injury (TBI), we performed an acute traumatic brain injury model in adult rats. Western blot analysis, immunohistochemistry and RTPCR revealed that BMP-10 expression in impaired cerebral cortex was more strongly induced not only at protein level but also at mRNA level compared to that in normal group. Double immunofluorescence labeling suggested that BMP-10 was localized mainly in the cytoplasm of neurons, microglias, and astrocytes within 3 mm from the lesion site at day 3 post-injury. And there was a specific upregulation of BMP-10 in astrocytes following brain injury. Besides, co-localization of BMP-10 and proliferating cell nuclear antigen (PCNA) was detected in Glial fibrillary acidic protein (GFAP) (+) cells. We also examined the expression profiles of PCNA and GFAP whose change was correlated with the expression profiles of BMP-10 in the incised injury model used here. Another experiment in which astrocytes were treated with BMP-10 was also performed to confirm the relationship between the upregulation of BMP-10 and proliferation of astrocytes following TBI. Taken together, this is the first description of BMP-10 expression during the central nervous system (CNS) lesion and repair. Thus, the present data suggested that BMP-10 may be implicated in CNS pathophysiology after TBI. But, further studies are needed to understand the cell signal pathway which can direct the exact role of BMP-10 following traumatic brain injury.