嗅鞘细胞移植脊髓全横断损伤大鼠大脑皮质运动区转化生长因子β表达的影响

背景：多项研究已证实嗅鞘细胞能促进脊髓损伤大鼠神经功能的恢复，但其分子机制还不清楚。 目的：观察嗅鞘细胞移植对脊髓全横断大鼠大脑皮质运动区转化生长因子β mRNA表达的影响。 方法：采用酶消化法培养GFP转基因小鼠嗅鞘细胞，制成细胞悬液。建立SD大鼠T9脊髓全横断模型，造模后分为假手术组、模型组和嗅鞘细胞移植组。应用RT-PCR方法检测各组大鼠大脑皮质运动区转化生长因子β mRNA的表达变化，用β-actin作内参。 结果与结论：模型组大鼠造模后3 d大脑皮质运动区转化生长因子β mRNA的表达量高于假手术组(P < 0.05)，造模后7，14，21和28 d回到假手术组水平。嗅鞘细胞移植后21 d，嗅鞘细胞移植组转化生长因子β mRNA的表达量低于模型组(P < 0.05)。提示全横断脊髓损伤致大脑皮质运动区转化生长因子β mRNA早期表达上调，随后与假手术组相比无差别；嗅鞘细胞移植后期可逆转转化生长因子β mRNA的表达变化，有助于脊髓损伤的恢复。

Effect of olfactory ensheathing cells transplantation on the expression of transforming growth factor beta in the motor cortex of rats subjected to spinal cord transection

BACKGROUND: Many studies have showed that olfactory ensheathing cells (OECs) transplantation can result in significant functional improvements in rats subjected to spinal cord injury, but the underlying molecular mechanisms is not unknown. OBJECTIVE:To observe the effect of OECs transplantation on the expression of transforming growth factor beta (TGF-β) mRNA in the motor cortex of the rats subjected to spinal cord transection. METHODS:OECs isolated from transgenic mice expressing GFP and cultured by enzymatic digestion were made into cell suspension. Model of spinal cord transection (SCT) was established by cut transversely Sprague-Dawley (SD) rats T9 segment. After modeling, the rats were divided into sham-operation group, operation group and OECs transplantation group. RT-PCR was employed to detect gene expression of TGF-β. β-actin was used as control. RESULTS AND CONCLUSION:RT-PCR results showed that compared with sham-operation group, the gene expression of TGF-β in the motor cortex increased significantly at 3 days postoperatively in the operation group (P < 0.05), and it returned to the level of sham-operation group at 7, 14, 21, and 28 days after modeling. Following OECs transplanatation, the expression of TGF-β in motor cortex at 21 days postoperatively showed a significant decrease compared with the operation group (P < 0.05). The findings indicate that spinal cord transection results in the up-regulation of the expression of TGF-β mRNA in the motor cortex in early period. OECs engrafted can decrease the expression of TGF-β mRNA in the later time so as to promote the recovery of spinal cord injury.