骨形态发生蛋白及其受体在正常成年大鼠脊髓中的表达分布

摘要

目的:观察骨形态发生蛋白(bone morphogenetic proteins,BMPs)及其受体在正常成年大鼠脊髓中的表达分布.方法::取正常成年大鼠脊髓并切片,运用免疫组织化学方法分别检测BMP2,4,7及其受体BMPR Ⅰa,BMPR Ⅰb,BMP Ⅱ的表达.结果:在正常成年大鼠脊髓的前角运动神经元、背角感觉神经元、少突胶质细胞、部分小胶质细胞和部分星形胶质细胞表达BMPR Ⅰa和BMPR Ⅰb.少突胶质细胞及灰质前角运动神经元表达BMPR Ⅱ受体,灰质神经胶质纤维酸性蛋白(glial fibrillary acidic protein,GFAP)阳性的星形胶质细胞未见BMPR Ⅱ受体表达,白质的部分GFAP阳性的星形胶质细胞表达BMPR Ⅱ受体.免疫组织化学未检测出BMP2,4在正常成年大鼠脊髓中表达.BMP7在所有的APC阳性的少突胶质细胞及NeuN阳性的前角运动神经元中表达,在正常脊髓的部分星形胶质细胞中可见表达.磷酸化的pSmad 1/5/8蛋白表达见于所有的少突胶质细胞及神经元、部分星形胶质细胞以及软膜下脊髓周边GFAP阳性的星形胶质细胞,这些细胞也是RC2阳性细胞(即放射状胶质细胞).结论:BMP2,4在正常成年大鼠脊髓中不表达,BMP受体、BMP7及磷酸化的pSmad 1/5/8蛋白在正常成年大鼠脊髓的多种细胞中表达,提示BMP信号在成体脊髓神经元及胶质细胞功能中起重要作用.%Objective To observe the expression distribution of bone morphogenetic proteins (BMP) in the spinal cord of normal adult rats. Methods Expression of BMP2, BMP4, and BMP7, and their receptors BMPR Ia, BMPR Ib, and BMP Ⅱ were detected by immunochemistry analysis in the spinal cord of normal adult rats. Results Expression of BMPR Ia or BMPR Ib was observed in the motor neurons of the anterior horn, sensory neurons of the dorsal horn, oligodentrocytes, some microglia, and some astrocytes. Expression of receptor BMPR Ⅲ was found in the oligodentrocytes and motor neurons in the gray matter of anterior horn. It was also expressed in some glial fibrillary acidic protein (GFAP)-positive astrocytes in the white matter but not in the gray matter. BMP2 and BMP4 were not expressed in the spinal cord of normal adult rats by immunohistochemistry. BMP7 was expressed in all the APC-positive oligodentrocytes, all the NeuN-positive motor neurons in the anterior horn, and some astrocytes in the normal spinal cord. Phosphated pSmad 1/5/8 protein was expressed in all the oligodentrocytes, all the neurons, and some astrocytes, especially in the GFAP-positive astrocytes which were RC2-positive radial glia in the subventricular zone. Conclusion BMP7, BMP receptors, and phosphated pSmad 1/5/8 are expressed in many types of cells whereas BMP2 and BMP4 are not expressed in the spinal cord of normal adult rats, which suggests an important function of BMP signal pathway in the neuron and glia of spinal cord