脊髓损伤过程中β-1,4半乳糖基转移酶的表达研究

Spatiotemporal expression of β-1,4-Galactosyltransferase after spinal cord transaction in rats

目的 探讨β-1,4半乳糖基转移酶（β-1,4-GalT）在横断性脊髓损伤后的时空表达变化以及细胞定位情况.方法 将42只成年SD大鼠随机分为假手术组和T9横断伤8 h、1 d、3 d、5 d、7 d、14 d组,每组6只.采用实时定量PCR测定损伤后各时间段β-1,4-GalT在脊髓中的表达变化;采用原位杂交与免疫荧光标记方法检测β-1,4-GalT在脊髓中的分布以及伤后的定位改变.结果 脊髓横断损伤后,β-1,4-GalT-Ⅴ在损伤上、下段表达高峰分别出现在损伤后8 h和1 d,之后逐渐下降,至伤后14 d降低至假手术组水平.增高的mRNA主要分布于损伤周围的细胞中及脊髓后角浅层的感觉神经元中.荧光原位杂交结果显示,β-1,4-GalT-Ⅴ主要分布于巨噬细胞和小胶质细胞以及病理状态下的少突胶质细胞.同时β-1,4-GalT-Ⅴ mRNA在损伤后大量表达于富含P物质和IB-4的脊髓后角浅层的感觉神经元中.结论 脊髓损伤后β-1,4-GalT在基因和细胞水平呈现明显的时空变化,并且与巨噬细胞和小胶质细胞以及病理状态下的少突胶质细胞存在共定位.该酶可能参与了损伤后的继发性损伤,即伤后早期的炎性反应,并可能与脊髓损伤后的神经病理性疼痛有关.

Objective To study the gene expression and subcellular localization of β - 1,4 - GalT -Ⅴ after spinal cord injury（SCI）. Method Spinal cord transection models were established in adult Sprague Dawley rats. Real - time PCR was used to detect the spatiotemporal expression of β - 1 ,4 - GalT - Ⅴ mRNA after SCI. Also, the changes of β - 1,4 - GalT - Ⅴ localization after injury were investigated by in situ hybridization and immunofluorescence double staining. Results The expression of β - 1,4 - GalT - Ⅴ mRNA increased gradually after SCl,with a peak level at 8 hour to 1 day after injury. β - 1,4 - GalT - Ⅴ - positive cells localized mainly in neurons of gray matter and mostly overlapped with ED - 1 - positive macrophages 1d after SCI, partly colocalized with microglia and oligodendrocytes. Conclusions After SCI in vivo, there is significant variation of β - 1 ,4 - GalT - Ⅴ mRNA. It is dominantly expressed by macrophages, microglia,oligodendrocyte cells and sensory neurons. These results indicate that β - 1,4 - GalT - Ⅴ may participate into the pathophysiologic response after SCI,which provide new insight into further research of mechanism of SCI.