Effect of pulmonary edema after seawater drowning on traumatic brain edema in rats

Objective To investigate the effect of pulmonary edema after seawater drowning(PE-SWD) on traumatic brain edema in rats.Methods Seventy-two male Sprague-Dawley rats were randomly divided equally into 9 groups: ①1-hour group with simple traumatic brain injury(TBI,resulting from lateral fluid percussion);②6-hour group with simple TBI;③1-hour group after brain trauma with freshwater drowning;④6-hour group after brain trauma with freshwater drowning;⑤1-hour group after brain trauma with seawater drowning;⑥6-hour group after brain trauma with seawater drowning;⑦6-hour electron microscopy(EM) group after TBI;⑧6-hour EM group after brain trauma with freshwater drowning;⑨6-hour EM group after brain trauma with seawater drowning.In group ① to ⑥,the brain tissue water content and the ion content including Na+,K+ and Ca2+ were detected,and the pathology was evaluated.In group ⑦ to ⑨,the injured brain was scanned by electric microscopy.Results Compared with the TBI group and the freshwater drowning group,PE-SWD significantly exacerbated the traumatic brain edema,increased the contents of Na+ and Ca2+,and decreased the content of K+.The findings under the light and electric microscopes also confirmed that PE-SWD could exacerbate the traumatic brain injury.Conclusion PE-SWD contributes a lot to traumatic brain edema or secondary brain injury.