周围神经损伤后巨噬细胞游走抑制因子mRNA在许旺细胞的表达状况

Expression of macrophage migration inhibitory factor mRNA in Schwann cells

目的 探讨周围神经损伤后 ,许旺细胞表达巨噬细胞游走抑制因子 (macrophagemigrationinhibitoryfactor,MIF)mRNA的变化 ,明确许旺细胞及MIF在激活巨噬细胞、促进神经再生中的作用。 方法 取 50只大鼠 ,随机分为 1 0组 ,每组 5只。 1组设为正常对照组 ,其余 9组分别在预损伤坐骨神经后 1、1 2h及 1、3、7、1 0、1 4、1 7、2 1d ,分离纯化许旺细胞 ,提取RNA。采用半定量RT PCR法检测RNA的水平。经图像分析测出正常及各预损伤组MIFmRNA的相对水平。 结果 许旺细胞中MIFmRNA的表达量在神经损伤后 1 2h开始出现明显升高 (0 342 0± 0 0 0 2 6) ;伤后 7d达到最高(0 6388± 0 0 0 2 0 )后 ,维持在较高水平 ;至伤后 1 0d(0 6397± 0 0 0 2 3)开始缓慢下降 ;2 1d(0 2 76 4±0 0 0 2 7)后恢复至伤前水平。 结论 周围神经损伤后 。

Objectives To investigate the expression of macrophage migration inhibitory factor (MIF) mRNA in Schwann cells after peripheral nerve injury and roles of Schwann cells and MIF in macrophages activation and nerve regeneration. Methods Fifty SD rats were divided into 10 groups. One group served as normal control. The rest were anesthetized with 3% sodium pentobarbital (30 60 mg/kg, i p) and sciatic nerves were transected distal to the obturator tendon respectively 1 h, 12 h, 1 d, 3 d, 7 d, 10 d, 14 d, 17 d and 21 d before being killed. Sciatic nerves were resected and connective tissues excised. Schwann cells were obtained by digesting the nerve tissues with trypsin and collagenase. RNA was isolated and reverse transcription polymerase chain reaction (RT PCR) was carried out. cDNA was analyzed by automatic system and the parameters were assessed to define the status of MIF mRNA expression in different groups. Results The level of MIF mRNA started to increase 12 h after the nerve transection The level remained high from day 7 up to 10 after the injury During the period from days 10 to 21, MIF mRNA decreased slowly to the pre transection level. Conclusion After peripheral nerve injury, Schwann cells can secrete MIF which may play a pivotal role as an immunomodulatory cytokine in macrophage activation and inflammatory reaction.