硫酸皮肤素在小鼠脑外伤后的经时表达

Immunohistochemical localization of dermatan sulfate in mouse brain after traumatic injury

目的探讨硫酸皮肤素(DS)在小鼠脑外伤后的经时表达及其与纤维性瘢痕产生的相关性。方法选用10周龄小鼠制备黑质纹状体通路损伤模型,术后1、4、7、14d取脑行冷冻切片。应用GD3A12和LKN1抗体特异性识别硫酸软骨素的一个亚型——DS的表达,同时应用纤连蛋白(FN)抗体探讨纤维性瘢痕的产生过程,应用免疫荧光法探讨两者的相关性。结果在正常成年小鼠大脑中,GD3A12和LKN1免疫反应只出现在脑膜及脑表面的血管。在伤后4d的鼠脑,损伤周边的某些细胞中发现DS的表达,其后在损伤部位的纤维性瘢痕中DS表达增加。双重免疫荧光显示,DS与FN共同定位于脑膜细胞迁移而形成的纤维性瘢痕。虽然纤维性瘢痕也有巨噬细胞和反应性星形胶质细胞紧密包绕,但DS未表达在巨噬细胞和星形胶质细胞。结论在脑损伤后,DS的定位只限于纤维性瘢痕的纤连蛋白阳性细胞,由此推论DS可能在纤维性瘢痕形成中起着一定的作用。

Objective To investigate the immunohistochemical localization of dermatan sulfate （DS） and its correlation with the fibrotic scar formation in the mouse brain after traumatic injury. Methods The nigrostiatal dopaminergic pathway was unilaterally transected in 10-weeks-old male ICR mice. The operated mice were sacrificed and the brains were obtained 1 , 4, 7 and 14 days after injury. Immunohistochemieal localization of DS was examined using the antibodies GD3A12 and LKN1 which specifically recognize DS subtypes. The fibrotic scar formation was evaluated by the fibronectin antibody and its correlation with DS localization was investigated by double immunofluorescent staining. Results In normal adult mice brains, the localization of GD3A12 and LNK1 immunoreaetivity was in meninges and blood vessels of the brain surface. At the 4th day after injury, the first DS immunoreactions appeared in some cells at the edge of the lesion site and a dense deposition of DS immunoreaetivity was in the central region of the lesion site where FN-immunoreactive fibroblast formed the fibrotic scar afterwards. Double immunofluorescent staining demonstrated that intense DS immunoreactivity was localized in the fibrotic scar of the lesion core and was almost completely overlapped well with FN immunoreactivity, but not with CD45-immunoreactive macrophages and glial fibrillary acidic protein （GFAP）-positive reactive astrocytes. Conclusion The localization of DS immunoreactivity after brain injury is confined in the fibroblast of the fibrotic scar, suggesting that DS may play some role in the formation of the fibrotic scar.