| Purpose: With the growing of human competition for Marine resources,it's more and more possible to go to war at sea.Naval craft is crucial to win a sea battle.Moreover,most of the ship cabins are closed space as we know it.So it is more valuable to research the characteristic and mechanism of blast injury in closed space and its emergency treatment.Based on the actual combat,this research built a full-scale model of multiple cabin and we chose the naval gun as the explosive source.The objective of this study is to investigate characteristics of the blast in military ship's closed cabin attacked by naval gun in simulated modern battlefield and to analyze the relationship between the blast injuries and injury factors,such as location,fragment and shock wave.Ultimately,we look forward to lay a foundation of the diagnosis and treatment of modern sea war injury.Methods: Two kinds of conventional naval gun were exploded in a 1:1 model of closed cabin according to the typical internal structure of the core part of a normal ship.After blast,the experimental animals were examined to identify their injury condition after X-ray examination.Death animals were dissected immediately,but live animals raised in single cages will be dissected after 24 hours watching.We dissect for analyzing the cause of death and damage characteristics.In the meantime,we need to collect the spinal cord specimens.After collecting the data,we summarize the casualty rate and its correlation with cabin structure.The data ware analyzed using SPSS 21.0 software.In addition,we further analyzes the damage characteristics of spinal cord injury in a closed cabin after formalin fixed,paraffin embedding and sectioning: HE staining to observe spinal cord tissue morphology change,TUNEL staining to detect apoptosis cell,immunohistochemical staining to detect the expression of Caspase 3,an apoptosis related proteins.Results: The study with a total of 76 different animals.The overall mortality rate was 59.2%.The mortality rate between live ammunition(63.2%)and naked(55.3%)shell has no significant difference(P>0.05).The mortality rate of lager caliber ammunition group(73.7%)is evident higher than small ammunition group(44.7%)(P<0.05).Among the different closed cabin,the mortality rate of smaller ammunition group is no obvious difference(P>0.05).While in lager caliber ammunition group,the mortality rate of each cabin is not all equal(P=0.000).The leading cause of death is important organ injuries caused by shock waves and explosive fragments,and there was found to be no obvious difference(P>0.05).Activity ability score of surviving animals after explosion shows the activity ability decline over time in the explosive cabin group and the adjacent cabin group before rack.In other groups,the activity ability has no significant change.Pulmonary blast injury assessment shows,animals in explosive cabin group and the adjacent cabin group before rack all have moderate to severe lung injury;animals in the adjacent cabin group after rack were observed mild lung injury;animals in the separated cabin survive group have no obvious lung damage with a few exceptions.The incidence of spinal fracture is 7.1%,the fragments and throwing are the major cause of spinal fracture.Subarachnoid hemorrhage,intramedullary vascular disruption can be observed by means of Gross anatomy and HE staining.In cell level,Counting the number of spinal cord anterior horn motor neurons,it is significant different between the instant death group and the survive group(P<0.05).Among living animals,the explosive cabin group and the adjacent cabin group before rack have the least motor neurons numbers,and there was found no obvious difference(P>0.05).The Followed are the adjacent cabin group after rack and the separated cabin group(P<0.05).In TUNEL cell apoptosis staining,apoptotic cell count of the instant death group is significantly less than the survive group(P<0.05).Among living animals,the explosive cabin group and the adjacent cabin group before rack have more apoptosis cells,and it's no significant difference between the two groups(P>0.05).The adjacent cabin group after rack have less apoptosis cells than the above groups,but its more than the separated cabin group(P<0.05).There were no significant difference about Caspase-3 protein positive expression among the instant death group and the two survive groups,the explosive cabin group and the adjacent cabin group(P>0.05).The Followed were the adjacent cabin survive group after rack and the separated cabin survive group(P<0.05).Conclusions: The casualty rate of explosion in large caliber ammunition group is significantly greater than the small ammunition group.The injury type and mortality between live ammunition and naked have no obvious difference.Mortality is different at different positions of cabin,and in a certain range,the overall structure and internal cabinet of ship cabin have apparent protective effect to the seaman and their spinal cord.Shock injury is the main types of spinal cord injury after the explosion.Cell apoptosis is the main performance when observed in cell level.Degree of spinal cord injury is positively associated with the degree of lung injury.Moderate to severe lung damage indicate heavier spinal cord injury.The above injury characteristics provide a new direction for protection and treatment of explosion and early diagnosis of explosive injury of spinal cord. |
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