运动神经损伤早期脊髓Calpain-2的上调促进IL-6的异常表达

Increased Calpain-2 Upregulates Expression of IL-6 in Spinal Cord Early after Motor Nerve Injury

【目的】探讨L5前根切除损伤运动神经的慢性痛模型中早期脊髓内钙依赖性蛋白水解酶Calpain-2(CALP2)介导白细胞介素-6(IL-6)异常表达的病理生理。【方法】采用免疫荧光组织化学和蛋白免疫印迹法,观察L5-VRT后L5背根、脊髓内CALP2的表达改变以及术前预处理calpain抑制剂MDL28170对脊髓内L5-VRT诱导的IL-6异常表达的影响,同时观察单纯给予外源性CALP2(rat recombinant calpain-2,rr-CALP2)对正常大鼠脊髓内IL-6表达的影响。【结果】(1)L5-VRT诱导邻近L5背根以及脊髓背角和前角内钙依赖性蛋白酶CALP2表达升高;(2)通过术前预处理calpain抑制剂MDL28170(25 mg/kg)部分阻断L5-VRT诱导的双侧脊髓IL-6异常表达;(3)在正常大鼠单侧L5背根表面给予rr-CALP2可直接诱导双侧脊髓IL-6蛋白水平升高。【结论】运动神经损伤早期可能首先通过损伤处CALP2的激活,诱导脊髓IL-6异常表达,参与慢性痛的产生。

【Objective】To discuss the role of calpain-2(CALP2)on abnormal expression of interleukin-6(IL-6)in spinal cord early after motor nerve injury by L5 ventral root transection(L5-VRT).【Methods】Immunohistochemistry and Western blot were used to examine the early expression of CALP2 in ipsilateral L5 dorsal root and bilateral spinal cord.Furthermore,we also observe the effect of calpain inhibitor MDL28170 on the up-regulation of spinal IL-6 induced by L5-VRT,as well as the effect of rat recombinant calpain-2(rr-CALP2)on spinal IL-6.【Results】In present experiment,L5-VRT increased the immunofluorescence intensity of CALP2 in the ipsilateral L5 dorsal root and bilateral spinal dorsal horn and ventral horn 0.5 h after surgery.Pre-treatment with calpain inhibitor MDL28170(25 mg/kg)partly blocked the el?evation of IL-6 induced by L5-VRT.Administration of rr-CALP2 on the surface of unilateral L5 dorsal root triggered the up-regulation of IL-6 protein levels in bilateral spinal cord in normal rats.【Conclusion】These data suggested that the early increased IL-6 in spinal cord induced by L5-VRT was mediated by CALP2 activity.