利拉鲁肽对大鼠急性脊髓损伤后神经细胞自噬与运动功能恢复的作用

Effect of Liraglutide on neuronal autophagy and movements recovery after spinal cord injury in rats

目的探讨利拉鲁肽注射液(Liraglutide)对急性脊髓损伤(spinal cord injury,SCI)后神经细胞的保护作用及其可能机制。方法 54只SD大鼠随机分成假手术组(Sham组)、脊髓损伤组(SCI组,损伤后立即腹腔注射0.9%氯化钠注射液50μg/kg)和治疗组(Liraglutide组,损伤后立即腹腔注射利拉鲁肽50μg/kg),每组18只,Allen法建立大鼠脊髓损伤模型,于损伤后3 d取脊髓组织,Western blot检测LC3-Ⅱ、Caspase-3表达,免疫荧光双标染色观察神经元自噬表达水平、神经细胞凋亡情况;于损伤后1 d、3 d、7 d分别进行Basso Beattle Bresnahan(BBB)运动评分。结果与Sham组相比,SCI组LC3-Ⅱ、Caspase-3表达、自噬阳性神经细胞数目、神经细胞凋亡数目均增多(P<0.01),BBB评分显著降低(P<0.01);Liraglutide组与SCI组相比,LC3-Ⅱ显著增多,Caspase-3表达降低(P<0.01);免疫荧光双标染色示自噬阳性细胞数目明显增多(P<0.01);神经元凋亡双标染色法示神经凋亡细胞数目明显减少(P<0.01);BBB评分在3 d与7 d时有显著提高(P<0.01)。结论利拉鲁肽增强大鼠脊髓损伤后神经细胞自噬,降低凋亡相关蛋白表达,减少神经细胞凋亡,促进大鼠运动功能恢复,对脊髓损伤具有保护作用。

Objective To explore the neuroprotective effect and possible mechanism of Liraglutide in the rat model of spinal cord injury （SCI）.MethodsFifty-four SD rats were randomly divided into three groups： sham operation group （n=18）, spinal cord injury （SCI） group （immediately received 50μg/kg saline injection intraperitoneally after injury, n=18） and Liraglutide group （immediately received 50μg/kg Liraglutide injection intraperitoneally after injury, n=18）. Spinal cord injury model was established using Allen＆#39;s method. The rats were sacrificed and the spinal cord tissue were taken out 3 days after injury. Western blot was used to analyze the LC3-Ⅱ and caspase-3 expression. Immunofluorescent double labeling was used to detect the autophagy positive neurons and neuronal apoptosis. Finally, behavioral assessment with Basso Beattle Bresnahan locomotor rating scale （BBB） was done at 1 d, 3 d and 7 d after injury.Results Compared with sham group, the expression of LC3-Ⅱ, the level of caspase-3 and the number of autophagy positive neurons and neuronal apoptosis increased significantly in SCI group （P〈0.01）, while the BBB score decreased significantly （P〈0.01）. Furthermore, compared with SCI group, Western blot showed that the expression of LC3-Ⅱ increased while the level of caspase-3 decreased in Liraglutide group （P〈0.01）. Immunofluorescent double labeling showed that the number of autophagy positive neurons enhanced significantly （P〈0.01） and the neuronal apoptosis in Liraglutide group reduced significantly compared with SCI group （P〈0.01）. Finally, behavioral assessment showed that animals in Liraglutide group achieved significant increase in BBB score on 3 d and 7 d （P〈0.01）.Conclusion Liraglutide promotes neuronal autophagy, decreases neuronal apoptosis and improves the locomotor function after SCI. Liraglutide may be a new candidate for clinical application in the treatment of SCI.