The Effect Of Hyperbaric Oxygen On The Survival Rate Of Rats After Resuscitation From Traumatic Shock

ObjectiveTo investigate systematically the role of HBO treatment after resuscitation from traumatic shock and observed the effect of HBO on the oxidation-antioxidation system,inflammatory reaction,tissue metabolism,morphology change and the survival rate of rats after resusciation from traumatic shock,and elucidate underlying the mechanisms.Materials and Methods1.Animal subgroupWistar rats were randomly divided into two major groups.The first major group were 96 rats,and then they were randomly divided into four groups again,every groups were 24 rats:Control group(C)—No shock and resuscitation,just the surgical operation was done;Shock group(S)—The surgical operation was done to induce traumatic shock and then the rats were resuscitated with shed blood and normal saline;One-time HBO group(HⅠ)—The surgical operation was done to induce traumatic shock and then the rats were resuscitated with shed blood and normal salinel.After the resuscitation,the rats were immediately treated by HBO one time in 24 hours; Three-times HBO group(HⅢ)—All the operation is same as that of One-time HBO group,except that the rats were treated by HBO three times in 24 hours.The rats in this major group were used to get the specimens,and then the biochemical indicators were detected,the pathobiology examination was done.The second major group were 40 rats,and they were also divided into four groups,every groups were 10 rats:Control group(C),Shock group(S),One-time HBO group(HⅠ),Three-times HBO group (HⅢ).Every groups' operation were same as those of the first major group.The rats in this major group were used to caculate survival rate of the 24th,36th,48th,72nd hour.2.The establishment of traumatic shock and rususcitation modelAfter the rat had been anesthetized successfully,it was fixed at dorsal position.A trochar was inserted into the right femoral artery,and the trochar was linked to a blood pressure transducer which connected to a multiparameter patient monitor,then the blood pressure can be monitored via this polygraph.The left jugular vein was cannulated with a trochar as to administer normal saline and shed blood for the resuscitation.The right carotid artery was also cannulated with a trochar,so blood can be withdrawn.A falling iron mass smashed to the left thight of rat vertically,and caused the fracture of femur and the crush of musle tissue.At the same time,blood was withdrawn through the trochar into the heparinized syringe,and it made the mean artery pressure descend and shock.After 60 minutes of hypotension,the rat was resuscitated by transfusing the all shed blood and normal saline.The mean artery pressure should be above 70-80mmHg after the resuscitation.3.The practice of hyperbaric oxygen(HBO)The rat was put into the hyperbaric oxygen chamber.The chamber was washed three times.Then the pressure of the chamber was made raise to 0.15MPa with a constant speed and the oxygen concentration of the chamber was higher than 99.5%.Then the constant pressure and oxygen concentration of the chamber would be maintained for 60 minutes.Finally,the pressure of chamber was decreased with a constant speed.When the pressure of chamber was 0MPa,the rat was taken out.4.The determination of biochemical indicatorThe time of before shock,after shock,after resuscitation and after 24 hours were defined as four time points of detection.According the four time points,the rats of every group of the first major group were divided into 4 subgroups:Before shock,After shock,After resuscitation,After 24 hours.Every subgroup were 6 rats.According to the corresponding time points,the rats of every subgroup were killed and the plasma was taken out.The activity of plasma SOD,iNOS was measured,and the concentration of plasma TNF-α,MDA,NO,lactic acid was determined too.5.Histopathological examinationAfter 24 hours,the specimens were excised from the live rats.A part of the lower lobe of the left lung,the terminal ileum,the left lobes of liver and the left kidney were taken out.The specimen was fixed and cut into slices,and then the slices were stained. Finally,the slices were examined via a light microscopy and the histopathological change was scored.6.The caculation of survival rateThe 40 rats of the second major group were randomly divided into 4 groups and every group were 10 rats:Control group(C),Shock group(S),One-time HBO group (HⅠ),Three-times HBO group(HⅢ).Every group's operation was same as that of the first major group.After the operation,all the rats were put into a cotton quilt at room temperature(25℃),and they would be observed for 72 hours.The survival time was recorded,and the survival rate of the 24th,36th,48th,72nd hour was calculated.7.Statistical analysisThe data was dealt with the SPSS13.0 For Windows software.The data of biochemical indicator and pathological score was indicated as Mean±Standard Deviation((?)±s),and the groups were compared with SNK-q test of One-Way analysis of variance(One-Way ANOVA).The correlation analysis was done by the Pearson's Bivariate of Correlate.The survival rate was calculated with life stable method and the result was indicated as Survival rate±Standard Error(P±S_p).The survival rate of groups were compared with Log-Rank test.Differences were considered significant when P＜0.05. Results1.The activity superoxide dismutase(SOD)of plasmaAfter 24 hours,the activity of plasma SOD of the group S was significantly lower than that of the group C(P＜0.05),and the activity of plasma SOD of the group HⅠand HⅢwere higher than that of the group C and S,but the difference with the group C was not significant(P＞0.05),whereas the difference with the group S was greatly significant (P＜0.05).Although the activity of plasma SOD of the group HⅢwas higher than that of the group HⅠ,the difference between them was not significant(P＞0.05).2.The concentration malondialdehyde(MDA)of plasmaAfter 24 hours,the concentration of plasma MDA of the group S,HⅠand HⅢwere significantly higher than that of the group C(P＜0.05),whereas the concentration of plasma MDA of the group HⅠand HⅢwere significantly lower than that of the group S(P＜0.05).Although the concentration of plasma MDA of the group HⅢwas lower than that of the group HⅠ,the difference between them was not significant (P＞0.05).3.The concentration of tumor necrosis factor-α(TNF-α)of plasmaAfter 24 hours,the concentration of plasma TNF-αof the group S,HⅠand HⅢwere significantly higher than that of the group C(P＜0.05),whereas the concentration of plasma TNF-αof the group HⅠand HⅢwere significantly lower than that of the group S(P＜0.05).Although the concentration of plasma TNF-αof the group HⅢwas lower than that of the group HⅠ,the difference between them was not significant (P＞0.05).4.The concentration of nitric oxide(NO)of plasmaAfter 24 hours,the concentration of plasma NO of the group S,HⅠand HⅢwere significantly higher than that of the group C(P＜0.05),whereas the concentration of plasma NO of the group HⅠand HⅢwere significantly lower than that of the group S (P＜0.05).Although the concentration of plasma NO of the group HⅢwas lower than that of the group HⅠ,the difference between them was not significant(P＞0.05).5.The activity of induce nitric oxide synthase(iNOS)of plasmaAfter 24 hours,the activity of plasma iNOS of the group S,HⅠand HⅢwere significantly higher than that of the group C(P＜0.05),whereas the activity of plasma iNOS of the group HⅠand HⅢwere significantly lower than that of the group S (P＜0.05).Although the activity of plasma iNOS of the group HⅢwas lower than that of the group HⅠ,the difference between them was not significant(P＞0.05).6.The correlation analysis of the activity of iNOS and the concentration of NO of plasmaThere was a significant positive correlation between the levels of iNOS and NO (r=0.796,P＜0.001).7.The concentration of lactic acid of plasmaAfter 24 hours,the concentration of plasma lactic acid of the group S,HⅠand HⅢwere significantly higher than that of the group C(P＜0.05),whereas the concentration of plasma lactic acid of the group HⅠand HⅢwere significantly lower than that of the group S(P＜0.05).Although the concentration of plasma lactic acid of the group HⅢwas lower than that of the group HⅠ,the difference between them was not significant(P＞0.05).8.Histopathological injury scoreThe histopathological injury score of the lung,small intestine,liver and kidney of the group C were all significantly lower than that of the three other groups(P＜0.05). The histopathoiogical injury score of the lung,small intestine,liver and kidney of the group S were all significantly higher than that of the group HⅠand HⅢ(P＜0.05). Although the histopathological injury score of the lung,small intestine,liver and kidney of the group HⅢwere lower than that of the group HⅠ,all the differences between them were not significant(P＞0.05). 9.Survival rateThe survival rate of the group C was maintained with 1.00 in 72 hours,and the survival rate of the three other groups all presented a tendency of descend in 72 hours.The survival rate of the 24th,36th,48th,72nd hour of the group S were all significantly lower than that of the three other groups(P＜0.05).Although the survival rate of the 24th,36th,48th,72nd hour of the group HⅢwere all higher than that of the group HⅠ,the difference between them were not significant(P＞0.05).ConclusionsBased on the mechanism of HBO,this study discovered that the hyperbaric oxygen (HBO)treatment can improve tissue oxygen supply after the resuscitation from traumatic shock,and reduce the anaerobic metabolism.It can increase the activity of free radical scavenger,then lessen the damage that result from free radical,and especially can lessen the severity of lipid peroxidation.HBO can decrease the production of inflammatory factor after traumatic shock,therefore can inhibit the excessive inflammatory reaction.HBO can also lessen the histopathological injury of various organs.The above beneficial effects of HBO were reflected in the significantly increased overall survival rate of the rats after resuscitation from traumatic shock,Furthermore,the effect of three times HBO treatment in 24 hours after resuscitation from traumatic shock tend to be better than that of one time HBO treatment in 24 hours,but there was not significant difference between them.,so the further study should be carried out for the best practice plan of HBO for the treatment of traumatic shock and resuscitation from it.