The National Natural Science Foundation of China (General Program）；2020 Qing Lan Project of Jiangsu Province
目的：检测小鼠脊髓损伤（spinal cord injury, SCI）后B淋巴瘤Mo-MLV插入区1（B cell-specific MLV integration site-1, Bmi-1）在脊髓中的表达变化。方法：取2月龄C57Bl/6小鼠，利用LISA脊髓损伤造模仪制作小鼠第9胸椎节段（T9）中度脊髓钝挫伤模型，通过免疫荧光染色与western blot检测，初步观察SCI后1，3，7，14及28天时Bmi-1在脊髓中的表达变化与细胞定位。结果：Bmi-1在脊髓中的表达，于损伤后1天时即上调并达峰值，至损伤后28天时仍保持较高水平，其表达变化与增殖细胞核抗原（Proliferating Cell Nuclear Antigen，PCNA）的表达变化趋势相一致。免疫荧光染色结果显示：SCI后，Bmi-1与Iba-1、MBP、NeuN及CD31共表达；Bmi-1与GFAP无共表达。结论：小鼠脊髓损伤后脊髓中Bmi-1表达上调，主要定位于小胶质细胞、髓鞘细胞、神经元与血管内皮细胞，且在小胶质细胞的表达尤为显著。提示Bmi-1在脊髓损伤后的表达变化可能与小胶质细胞的增殖与活化、内源性髓鞘再生及血管内皮细胞的活化有关，可能在脊髓损伤后的病理过程中具有重要意义。
Objective: To explore the expression of B cell-specific MLV integration site-1(Bmi-1) in mice spinal cord after spinal cord injury (SCI). Methods: Two month-old C57Bl/6 mice received moderate contusion SCI at T9 using LISA impactor. The expression and cellular localization of Bmi-1 in spinal cord at the day of 1, 3, 7, 14 and 28 post SCI were detected by western blot and immunofluorescence staining. Results: The results of western blot showed that the expression of Bmi-1 was increased and achieved a peak value at day one post SCI, and which was higher than normal till to the day 28 post SCI. The tendency of the Bmi-1 expression was consistent with the expression of Proliferating Cell Nuclear Antigen (PCNA). The results of the immunofluorescence staining showed that the Bmi-1 was increased and co-localized with Iba-1, MBP, NeuN and CD31, but which was not co-localized with GFAP after SCI. Conclusion: The expression of Bmi-1 was increased and mainly localized in microglia, myelin cells, neuron, and endothelium, and especially in microglia after SCI. It suggests that the expression of Bmi-1 may relate with the proliferation and activation of microglia, the endogenous remyelination, and the activity of the endothelium. The Bmi-1 may involve in the pathological process after SCI.