重组人促红细胞生成素对大鼠急性脊髓损伤后炎症因子表达及运动功能的影响

Effect of recombinant human erythropoietin on expression of inflammatory factors and motor function after acute spinal cord injury in rats

目的研究重组人促红细胞生成素(rhEPO)对大鼠急性脊髓损伤(SCI)后肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)等炎症因子的表达及运动功能的影响,探讨其减轻脊髓损伤、保护神经功能的可能机制以及对运动功能恢复的影响。方法36只SD大鼠,采用随机数字表法分为假手术组(Sham组)、脊髓损伤组(SCI组)、治疗组(EPO组),每组12只。Sham组:不损伤脊髓,仅行椎板切除术;SCI组和EPO组:行椎板切除术后,均采用改良的Allen's撞击法造成脊髓损伤。EPO组于术后1 h、1 d、3 d、7 d、14 d腹腔注射rhEPO;Sham组及SCI组,于术后1 h、1 d、3 d、7 d、14 d腹腔内注射等量的0.9%氯化钠溶液。术后第3天,各组分别处死6只大鼠并取材,用酶联免疫吸附试验(ELISA)法检测TNF-α、IL-1β、IL-6的表达水平;并用脊髓损伤Basso-Beattie-Bresnahan(BBB)评分法评价大鼠术后第1、3、7、14天的运动功能情况。比较三组脊髓组织中各炎症因子表达情况及不同时间点BBB评分。结果术后第3天,Sham组的TNF-α、IL-1β、IL-6水平均低于SCI组及EPO组,EPO组的TNF-α、IL-1β、IL-6水平均低于SCI组,差异均具有统计学意义(P<0.05)。BBB评分最高分21分,Sham组无脊髓损伤,术后大鼠运动功能正常,BBB评分接近正常值。术后第1、3、7、14天,EPO组和SCI组大鼠的BBB评分随着时间的延长而升高,差异均具有统计学意义(P<0.05)。术后第1、3、7、14天,EPO组和SCI组大鼠的BBB评分均低于Sham组,差异均具有统计学意义(P<0.05)。术后第7、14天,EPO组大鼠的BBB评分分别为(10.04±1.01)、(12.50±1.17)分,均高于SCI组(7.92±1.04)、(9.92±1.12)分,差异均具有统计学意义(P<0.05)。结论rhEPO可减少急性脊髓损伤后炎症因子TNF-α、IL-1β、IL-6的表达,减轻炎症反应,从而发挥保护神经的作用;且rhEPO可明显改善脊髓损伤后大鼠的运动功能,有利于神经功能的恢复。

Objective To investigate the effects of recombinant human erythropoietin(rhEPO)on the expression of tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),interleukin-6(IL-6)and motor function after acute spinal cord injury(SCI)in rats,and to explore the possible mechanism of its reduction of spinal cord injury and protection of nerve function,as well as its effect on the recovery of motor function.Methods A total of 36 SD rats were divided into sham-operated group(Sham group),spinal cord injury group(SCI group)and treatment group(EPO group)by random number table method,with 12 rats in each group.Sham group:no spinal cord injury,only laminectomy;SCI group and EPO group:after laminectomy,modified Allen's impact method was used to cause spinal cord injury.EPO group was intraperitoneally injected with rhEPO 1 h,1 d,3 d,7 d and 14 d after operation.In the Sham group and SCI group,the same amount of 0.9%sodium chloride solution was injected intraperitoneally 1 h,1 d,3 d,7 d and 14 d after operation.On 3rd day after operation,6 rats in each group were killed and sampled,and the expression levels of TNF-α,IL-1βand IL-6 were detected by enzyme linked immunosorbent assay(ELISA).The exercise function of rats on the 1st,3rd,7th and 14th days after operation was evaluated by spinal injury Basso-Beattie-Bresnahan(BBB)score.The expression of inflammatory factors and BBB scores at different time points in the three groups were compared.Results At 3rd day after operation,the levels of TNF-α,IL-1βand IL-6 in Sham group was lower than those in SCI group and EPO group,and EPO group was lower than SCI group.Their difference was statistically significant(P<0.05).The highest BBB score was 21 points.There was no spinal cord injury in the Sham group.The postoperative rats had normal motor function,and BBB score is close to normal.On the 1st,3rd,7th and 14th day after operation,BBB scores of EPO group and SCI group increased with time,and the difference was statistically significant(P<0.05).On the 1st,3rd,7th and 14th day after operation,the BBB scores of EPO group and SCI group were lower than those of sham group,and the difference was statistically significant(P<0.05).On the 7th and 14th day after operation,the BBB scores of EPO group were(10.04±1.01),(12.50±1.17)points respectively,which were higher than those of SCI group(7.92±1.04),(9.92±1.12)points.The difference was statistically significant(P<0.05).Conclusion RhEPO can reduce the expression of inflammatory factors TNF-a,IL-1βand IL-6 after acute spinal cord injury,and reduce the inflammatory response,thereby playing a neuroprotective role.rhEPO can significantly improve the motor function of rats after spinal cord injury and is beneficial to the recovery of nerve function.