The Study Of The Role And Machanism Of Moderate Hypothermia To The Spinal Cord Ischemia/reperfusion Injury In Rabbits

Objects:To observe the locomotor functions,expression of IL-8 and histopathological exacebation of injured tissue of rabbits in spinal cord ischemiaVeperfusion injury under normothermia and hypothermia.To study the relationship between hypothermia ,neurological deficit and expression of IL-8,to investigate the role and machanism of hypothermia in spinal cord ischemia\reperflision injury.Methods :(l)Using the spinal cord ischemia\reperfusion model by occluding lumbar arteries,and the rabbits were divided into normothermia and hypothermia groups.Reperfusion for 30',4h,8h,12h,24h and 48h followed 40min's ischemia in two groups respectively .The locomotor and spinal function were evaluated(the function of leg extremties were evaluated by the Jacobs metheds,and sensory,motor and reflex function of spinal cord are scored through theReuter methoeds).(2)Using the same model,and after the reperfusion for 4h,8h,12h and 24h,the damage regions of spinal cord were removed and stained with HE and immurohistochemical to observe the histopathologic changes and expression of IL-8.ResuIts:(l)After 40min's ischemia,paralysis of legs can be observed,thenthere is a periodical recovery after blood reflow.But deterioration of spinal and locomotor functions are in direct ratio with time of reperfusion. In moderate hypothermia group,the functional deficit is less than that in normothermia group(P<0.05).(2)Positive expression of IL-8 in spinal tissues and PMNL aggregation increseaed following the reperfusion and histipathologic exacebation.(3)In different phase the positive expression of IL-8 and histopathologic exactation in hypothermia group is less than that in normothermia group.Conclusions:(l)there are positive relationship between the neuropathological deficit of spinal cord and progress of reperfusion. The systemic hypothermia of 31 to 33 C can alleviate the functional deteriorations evidently.it is a good treatment for ischermia\reperfusion injury of spinal cord.(2)There is a positive relationship between the expression of IL-8 and histopathologic exacebation.(3)Dring the spinal cord ischemia/reperfusion injury,diminishing the expression of IL-8 and the inhibition the secondary inflammation may be one of the machanisms that the moderate hypothermia alleviate the injuyr of spinal cord.