RESUMO
<p><b>OBJECTIVE</b>To observe the expression pattern of bone morphogenetic protein receptor IA (BMPR IA) in rats after contusive spinal cord injury.</p><p><b>METHODS</b>The expressions of BMPR IA, IB, and II were detected by immunochemistry in the spinal cord of normal adult rats, and the expression of BMPR IA was detected in the infinite horizons impactor model at 1, 3, 7, 14, 30, and 60 days after spinal cord injury.</p><p><b>RESULTS</b>In the spinal cord of normal adult rats, BMPR IA and II were expressed predominantly in the oligodentrocytes and neurons in the grey matter, and also in some astrocytes and numerous microglia cells. Only a low level of BMPR IB expression was detected in the neurons of the grey matter. After spinal cord injury, the expression of BMP IA markedly increased with sustained strong expression in the astrocytes till one month after the injury; its expression was also increased obviously in the microglia cells activated by the injury.</p><p><b>CONCLUSION</b>The expression of BMPR IA increases significantly in the astrocytes and activated microglia cells in rats after contusive spinal cord injury, suggesting the involvement of BMP signaling pathway in the physiological and pathological role of glia cells.</p>