The Effect Of Nimodipine On The Content Of Ca～(2+), Mg～(2+), ET In Brain Tissue And ET In Plasma After Diffuse Axonal Injury

Purpose :Diffuse axonal injury (DAI) of the brain closely relates to the severity of injury. Upto present, There are no effective treatment on it. The process of pathological changes of DAI were: misalignment of the intraxonal structure, axonal swelling and axons transsection, rather than division of axons directly. Many studies suggested the inflow of normally excluded extracellular might be the main pathogesis and mechanism of axonal injury and the neuronal Ca2+overload is one of the key factors in the development of DAI.Endothine are involved in many CNS functions and participate in a variety of disorders. Such as ischemia ,epilepsy and trauma.The Ca2+ channel blockor, Nimodipne ,may provide a potential important therapeutic approach in DAI. The aim of the present study were to investigate the effect of Nimodipine on the change of content of Ca2+ , Mg2+ and ET in brain tissue, ET in plasma and the water content in the brain tissue after severe head injury.Methods:72 adult Sprague-Dawley rats were divided into three groups randomly , (empty-group, control-group, and trial-group).Refering to the weight-drop device designed by Marmarou, the head-injury was established. The rats of trial-group were injected with Nimodipine by 0.2mg/Kg in five minutes, meanwhile after five minutes the same amount of normal saline was give to the control-group. And the empty-group were subjected to no disposal. The control-group and head-group were divided into 4 sub-groups according to the post traumatic disposal time. Every sub-group was composed of 8 SD and killed at the point of 30 minutes, 2 hour, 8hour and 24 hour after injury respectively. Then thecontent of Ca2+,Mg2+ and ET in brain tissues ET in plasma and the water content in brain tissue were measured in 5 rats of every sub-group. The others were for pathology study.Results: The post-traumatic content of Ca2+,ET and the water content in brain tissue of trial-group increased mildly and the Mg2+ reduced very little. There was a significant statistical difference between the trial-group and the control-group. In pathology study, The retraction ball (RB) as a form of DAI was distributed in cerebral matter and corpus callosum. Axonal swelling and retraction ball subside markedly in the trial-group.Conclusions: Nimodipine may significantly reverse the rise in the content of Ca2+,ET and the water content in brain tissues and the fall of Mg2+ and the increment of ET in plasma as well after DAI. As a result, Nimodipine possesses protective effect on brain and reduce these pathophsiological responses with in 24 hours afer injury, this might be the most ideal time for effective treatment.