磁刺激对脊髓损伤组织c-fos基因表达的影响

Effects of magnetic stimulation on c-fos gene expression of rats with spinal cord injury

目的 观察磁刺激对损伤脊髓组织中c -fos基因表达的影响。方法 用Allen氏WD法制造大鼠T8脊髓损伤的动物模型。 38只Wistar大鼠随机分为正常组 ( 6只 )、脊髓损伤治疗组 ( 16只 )和对照组 ( 16只 )。治疗组于术后 15min、1h、2h和 4h分别予以磁刺激 ( 0 .5Hz ,70 %最大输出强度 ) ,对照组无特殊处理。治疗组、对照组分别于术后 15min、1h、2h和 4h各取 4只动物处死 ,取损伤段脊髓组织 ,作石蜡切片 ,用地高辛标记的c -fos基因探针进行原位杂交 ,测定c -fosmRNA在损伤脊髓组织中的表达 ,用免疫组织化学方法检测fos蛋白的表达。结果 fos蛋白OD值在正常组为 3.78± 0 .72 ,在对照组明显增多 (最高达 16 .49± 1.3) ,而治疗组在各时段均低于对照组 (P <0 .0 1) ,c -fos基因表达在正常脊髓组织中呈弱阳性 ,在对照组中表达明显增加 ,治疗组c -fos基因表达的数目少于对照组 (P <0 .0 1)。结论 应用磁刺激能抑制脊髓损伤后c -fos基因的表达 ,这可能是磁刺激保护神经元并减轻脊髓继发性损伤的机理之一。

Objective To study the effects of magnetic stimulation (MS) on c-fos gene expression in spinal neurons of rats after spinal cord injury (SCI). Methods Thirty-eight Wistar rats were used, among them 32 rats underwent SCI with 10g×2.5cm impact at T8 level and were evenly divided into two groups: the MS group (n=16) and the control group (n=16), the other 6 rats served as the normal control. The rats in the MS group received 15 minutes, 1, 2 or 4 hours of MS at 0.5Hz and 70% of the maximal intensity output of the magnetic stimulator after the injury, while the rats in the other groups were not exposed to the MS. The c-fos mRNA levels of the rats were determined by in situ hybridization, the protein levels immunohistochemical methods. Results As compared with that in the normal controls (3.78±0.72), the c-fos protein expression increased significantly in rats with SCI in the control group (P<0.01), and this increase peaked at 2 hours after injury (16.49±1.30). The levels of c-fos expression in the MS group were significantly lower than those in the control group (P<0.01). Conclusion MS can inhibit the c-fos gene expression in spinal cord after injury, it may be one of the mechanisms that MS protects spinal cord against injury.