Pathophysiological Characteristics Of Rats Following Cold Seawater Immersion And Hemorrhagic Shock And Its Treatment

Trauma is the leading cause of death among people under 45 years old,and the incidence and mortality are increasing every year.Naval warfare is the main combat direction of our country in the future.In addition,with the rise of maritime transport,maritime operations,and far-sea tourism,maritime accidents occur frequently.People suffered damage from cold water and hemorrhagic shock,were severely injured,which lead to high mortality.During the falklands battle,the "general belgrano" sank,and more than 300 people died from cold seawater.Compared with the conventional environment,the pathophysiological changes and the mechanism of injury caused by cold seawater immersion and hemorrhagic shock have not been fully clarified.It is not clear whether there are more effective rewarming schemes and organ function protection measures.The study included three parts:(1)Pathophysiological characteristics and treatment of rats against cold seawater immersion and hemorrhagic shock;(2)Effects of different rewarming schemes on the damage caused by cold seawater immersion and hemorrhagic shock;(3)The protective effect of Mdivi-1 on the rats against cold seawater immersion and hemorrhagic shock.Methods:The 15? seawater immersion model and cold seawater immersion and hemorrhagic shock model were adopted.Blood was taken to detect blood gas,coagulation function,and vital organ function blood index.Detected the level of D-lactic.The organ blood was measured by Laser-speckle blood flow meter.The Core body temperature was monitored by cardiac output meter.The physiological recorder was used to measure hemodynamic data.Mitochondrial function analyzer was used to measure the changes of mitochondrial function.Use electron microscopy to survey the morphology of heart mitochondria.Experimental Protocols:Part I Pathophysiological characteristics and treatment of rats against cold seawater immersion and hemorrhagic shock.1.The cold seawater immersion and hemorrhagic shock model were adopted by SD rats,to observe the changes of survival rate and mean survival time for 72 h.2.To observe the changes in hemodynamic index,core body temperature,blood gas,mitochondrial,coagulation function,blood index of important organs,organs blood.Part II Effects of differ ent rewarming schemes on the damage caused by cold seawater immersion and hemorrhagic shock.1.Different rewarming methods were used to observe the effects of fast rewarming scheme and Intermittent rewarming scheme on the survival rate and mean survival time of rats for 72 h.2.To observe the changes with different rewarming schemes in hemodynamic index,core body temperature,blood gas,coagulation function,blood index of important organs,mitochondrial and blood flow of important organs.Part ? The protective effect of Mdivi-1 on the rats against cold seawater immersion and hemorrhagic shock.1.To observe the protective effect of Mdivi-1 on the morphology and function of rat mitochondria2.To observe the changes with Mdivi-1 in hemodynamic index,core body temperature,blood gas,coagulation function,blood index of important organs,mitochondrial and blood flow of important organs.Results:Part I Pathophysiological characteristics and treatment of rats against cold seawater immersion and hemorrhagic shock.1.The core body temperature of the rats was significantly reduced,the mean survival time was significantly shortened,and the survival rate was significantly reduced.2.The potassium and calcium ions were disordered,acidosis and coagulation dysfunction in rats after cold seawater immersion combined with hemorrhagic shock injury.The hemodynamic index decreased obviously.The blood indexes reflecting important organ function were significantly increased.Blood perfusion in liver,kidney and intestine was significantly decreased.Part II Effects of different rewarming schemes on the damage caused by cold seawater immersion and hemorrhagic shock.1.The core body temperature returned to normal after rewarming.Compared with the rapid rewarming,the internal environment of rates was stable after the step rewarming,and the variation range of the concentration of potassium and calcium ions was small.The survival time and the survival rate was increased.2.After rewarming,the blood coagulation function,acidosis,hemodynamic indexes,blood flow of liver,kidney and intestine were restored,and the blood indexes of heart function(CK-MB?cTnT)were significantly reduced.Although the blood index reflecting the liver and kidney function was slightly increased,the increase of the index in the step-up rewarming group was less than that in the rapid rewarming group.Part ? The protective effect of Mdivi-1 on the rats against cold seawater immersion and hemorrhagic shock.1.After cold seawater immersion and hemorrhagic shock,the number of mitochondria increased,and the damage was serious and mitochondria activity decreased.intermittent rewarming could partially restore mitochondrial activity and reduce mitochondrial damage.Mdivi-1 inhibits mitochondrial division and reduces the degree of mitochondrial damage.2.Mdivi-1 can significantly improve the hemodynamic index of rats.The blood index of important organ function decreased significantly;The blood flow of liver,kidney and intestine was basically restored.The degree of acidosis reduced;The survival time and survival rate of rats raised.Conclusion:1.After cold seawater immersion and hemorrhagic shock,the rat's internal environment was seriously disordered,the hemodynamic index was deteriorated,and the tissue perfusion was insufficient,leading to severe "lethal triad",high incidence of organ dysfunction,and survival time and survival rate significantly redused.2.Intermittent rewarming provides a stable internal environment for the recovery of low-temperature injury to the body,promotes hemodynamic stability,ensures blood perfusion to important organs,and plays an important role in correcting the "lethal triad" and protecting organ functions,thus significantly prolonging survival time and reducing mortality.3.The phenomenon of excessive mitochondrial division exists in the cold seawater immersion and hemorrhagic shock.Mditi-1 can inhibit the excessive mitochondrial division and maintain its function,thus achieving the purpose of protecting organ functions,extending survival time and reducing mortality.