Effects of wound irrigation with normal saline on rats with traumatic brain injury combined with seawater immersion

YANG Yang; YU Xia; HOU Pengwei; CHEN Li; XU Yongjun; WEI Liangfeng; WANG Shousen

Abstract：Objective After the rat model of traumatic brain injury combined with seawater immersion(TBI+SI)was established,normal saline was utilized to wash TBI+SI rats for the sake of diluting high permeability and alkalinity of seawater,ultimately aiming at evaluating therapeutic effect of normal saline.Methods Forty-eight healthy adult male rats were randomly and equally divided into Sham operation(Sham)group,traumatic brain injury(TBI)group,traumatic brain injury combined with seawater immersion(TBI+SI)group and normal saline irrigation(TBI+SI-NS)group,with 12 rats in each group.The TBI model was established by the method of controlled cortical injury.In Sham group,the scalp was cut and the dura mater was then exposed by grinding a 3.5 mm diameter bone window.Noticeably,the dura was unprocessed.In TBI group,rats were subjected to controlled cortical damage after an incision and a 3.5 mm-diameter ground bone window had been made on the scalp.The TBI+SI group received artificial seawater immersion in traumatic sites for 30 min after TBI.The TBI+SI-NS group was rinsed with sterile normal saline for 25 min on the basis of TBI+SI.Water content of the brain was tested via wet and dry weight method.Expression levels of tumor necrosis factor-α(TNF-α),interleukin-6(IL-6)and interleukin-1 β(IL-1β)in brain tissue were detected by ELISA.Pathological variation of brain tissue was observed by HE staining.Damage condition of neuronal mitochondria was observed by transmission electron microscope.Results Compared with the TBI group,the TBI+SI group had significantly increased brain water content(P＜0.01),up-regulated expression levels of inflammatory factors containing TNF-α,IL-6 and IL-1 β(P＜0.05,P＜0.01).Moreover,pathological changes of brain tissue and damage of neuronal cells in the cerebral cortex at the site of injury were more severe(P＜0.05).At 25min after washing the traumatic site of TBI rats with normal saline,not only the water content of brain tissue decreased(P＜0.05),but also expression levels of inflammatory factors TNF-α,IL-6 and IL-1β downregulated.Meanwhile,degrees to which brain tissue pathologically altered and neuronal cells damaged were alleviated.Conclusion Irrigation of traumatic sites in TBI+SI rats with normal saline relieved further damage of brain tissue and downregulated pathological changes of brain tissue as well as death of neuronal cells.Corresponding mechanism might be related to dilution of mineral salt concentration in seawater and reduction of seawater hypertonicity by normal saline.