七氟醚联合氙气预处理对脊髓缺血再灌注损伤模型大鼠的保护作用

Sevoflurance combined with xenon pretreatment protects against spinal cord ischemia-reperfusion injury in a rat model

背景:脊髓缺血再灌注损伤是一种严重的神经组织损伤,七氟醚及氙气均被报道对脏器缺血再灌注损伤有一定保护作用,但二者联合是否可以缓解脊髓组织损伤目前仍不明确。目的:探讨七氟醚联合氙气预处理保护大鼠脊髓缺血再灌注损伤的疗效及其机制。方法:60只SD大鼠随机分为假手术组、脊髓缺血再灌注组、七氟醚组、氙气组、七氟醚联合氙气组、七氟醚联合氙气+PI3K抑制剂LY294002组(SXI+LY组),每组10只。其中假手术组行假手术,七氟醚组、氙气组、七氟醚联合氙气组及SXI+LY组分别进行3.4%七氟醚、50%氙气、七氟醚联合氙气、七氟醚联合氙气+LY294002预处理,并行脊髓缺血再灌注损伤建模手术。比较各组大鼠的BBB后肢运动功能评分,尼氏染色和TUNEL染色观察脊髓组织中正常神经元和前角细胞的凋亡情况,Western Blot检测脊髓组织中PI3K、AKT和磷腺苷效应元件结合蛋白(cAMP-response element binding protein,CREB)的表达及其磷酸化情况。结果与结论:①七氟醚组、氙气组和七氟醚联合氙气组大鼠BBB后肢运动功能评分均高于脊髓缺血再灌注组,七氟醚联合氙气组的BBB后肢运动功能评分高于七氟醚组和氙气组,而SXI+LY组的BBB后肢运动功能评分低于七氟醚联合氙气组,差异有显著性意义(P均<0.001);②再灌注24 h后,七氟醚组、氙气组和七氟醚联合氙气组前角细胞凋亡指数低于脊髓缺血再灌注组,七氟醚联合氙气组低于七氟醚组和氙气组;SXI+LY组高于七氟醚联合氙气组,差异有显著性意义(P均<0.001);③与脊髓缺血再灌注相比,七氟醚组、氙气组和七氟醚联合氙气组脊髓组织中p-PI3K、p-AKT和p-CREB的表达均升高,其中七氟醚联合氙气组的表达最高,而SXI+LY组低于七氟醚联合氙气组,差异有显著性意义(P均<0.001);④提示七氟醚联合氙气预处理较单一应用对脊髓缺血再灌注损伤有更好的保护作用,其作用机制可能与对PI3K/AKT/CREB信号通路的影响有关。

BACKGROUND:Spinal cord ischemia-reperfusion injury is a serious nerve tissue injury.Both sevoflurane and xenon have been reported to have a certain protective effect on ischemia-reperfusion injury of viscersl organs,but whether the combination of the two can alleviate spinal cord injury is still unclear.OBJECTIVE:To study the protective effect and mechanism of sevoflurane combined with xenon pretreatment in the rats with spinal cord ischemia-reperfusion injury.METHODS:Sixty Sprague-Dawley rats were randomly divided into sham group,spinal cord ischemia-reperfusion group(IR),sevoflurane pretreated group(SI),xenon pretreated group(XI),sevoflurane and xenon pretreated group(SXI),PI3K inhibitor LY294002 group(SXI+LY),with 10 rats in each group.Sham group received sham operation,and the other groups received modeling operation for spinal cord ischemia-reperfusion injury.SI group,XI group,SXI group and SXI+LY group were pretreated with 3.4%sevoflurane,50%xenon,combination of sevoflurane and xenon,sevoflurane combined with xenon and LY294002(the inhibitor of PI3K)respectively.The hindlimb motor function of rats was evaluated using Basso,Beattie and Bresnahan(BBB)scores.Normal neurons and apoptosis of anterior horn cells in the spinal cord were detected by Nissl staining and TUNEL staining.The expression and phosphorylation levels of PI3K,AKT and cAMP-response element binding protein(CREB)in spinal cord tissue were detected by western blot.RESULTS AND CONCLUSION:The BBB scores for hindlimb motor function in the SI,XI and SXI groups were significantly higher than that in the IR group,and that of SXI group was significantly higher than that of SI group and XI group,while the BBB score in the SXI+LY group was significantly lower than that in the SXI group(all P<0.001).Twenty-four hours after reperfusion,the apoptotic index of anterior horn cells in the SI group,XI group and SXI group was significantly lower than that in the IR group,that in the SXI group was significantly lower than that in the SI group and XI group,while that in the SXI+LY group was significantly higher than that in the SXI group(all P<0.001).The expression of p-PI3K,p-AKT and p-CREB in spinal cord tissue was significantly increased in the SI group,XI group and SXI group as compared with the IR group,with a highest expression level in the SXI group,and the expression in the SXI+LY group was significantly lower than that in the SXI group(all P<0.001).Therefore,pretreatment using sevoflurane combined with xenon has a better protective effect against spinal cord ischemia-reperfusion injury than using single drug,and the mechanism may be related to the effect on PI3K/AKT/CREB signaling pathway.