Effects Of Dexmedetomidine Postconditioning On Caspase-3,IL-1β Expression And Blood-spinal Cord Barrier After Spinal Cord Ischemia-reperfusion Injury

Objective: To study the effects of dexmedetomidine postconditioning on expression of protein Caspase-3 and IL-1β,and blood-spinal cord barrier in rats with spinal cord ischemia-reperfusion injury.Methods: Choose 120 adult male Sprague-Dawley rats,and divide them randomly and evenly into 5 groups: sham group,IR group,DEX1 group,DEX5 group,and DEX10 group.Spinal cord ischemia-reperfusion injury was modelled by adopting the improved Zivin method.Normal saline and dexmedetomidine were injected into the rats with equal quantity with the help of the widely used micro-pump.The motor function of rats was evaluated quantitatively with score by adopting the Tarlov method 24 h after the reperfusion.For measurement of the permeability of blood-spinal cord barrier in spinal cord,the dyeing method with Evans Blue was used.The pathological changes of spinal cord were observed by HE staining,and the expression of protein Caspase-3 and IL-1β was assessed by the western blot.Results: By comparing the sham group and the other groups,it is found that lower extremity motor function score in IR group and DEX groups were much lower,spinal cord structure was damaged seriously,the number of neurons was decreased,the permeability of blood-spinal cord barrier was increased,and the expression of protein Caspase-3 and IL-1β were increased;Further,to compare the IR group and the DEX groups,the results show that lower extremity motor function score in DEX groups were significantly higher,damage of spinal cord structure injury was mitigated,the number of neurons was increased,the permeability of blood-spinal cord barrier was decreased,and the expression of protein Caspase-3 and IL-1β decreased based on results of the western blot;Finally,results of the DEX groups are compared with each other.Among them,the results of DEX1 and DEX10 groups show lower motor function score,more spinal cord injury and fewer neurons,that the permeability of blood-spinal cord barrier was decreased,and that Caspase-3 and IL-1β expression were increased visualized by western blot results.Conclusions: Dexmedetomidine postconditioning has obvious protective effect on SCIRI,which can maintain structure of BSCB and decrease the damage of spinal cord. This protective effect may work by activating the α2 adrenergic receptor,decreasing IL-1β expression in inflammatory reaction and degrading the anti-apoptotic effect of Caspase-3 expression.