Effects Of Vacuum Sealing Drainage Combined With Heparin Irrigation On Wound Pathological Changes In Scalded Rabbits With Seawater Immersion

Since China's reform and opening-up,marine industry developed quickly.Significant progress was made in the transport of navigation,fishery,scientific research,military and other aspects of maritime navigation.As China's ambition to build blue water navy,all kinds of fighting terrorism,piracy,marine rescue activities are increasing.The risk of the offshore workers suffer accidental trauma,burn,and shipwreck increased greatly,and has great possibility of sea falls after injury.Kidney,heart,liver,lung,and other important organs will have obvious pathological changes after burn patients suffered seawater immersion.Meanwhile be the first to bear,the burn wound is to suffer further damage.The special physical and chemical properties of sea water,such as hypertonic,high sodium chloride,high amount of bacteria,low temperature,alkaline can increase the microcirculatory disturbance of burn wound.The wound would progressively deepen,the necrosis range would increase,and the treatment would be more difficult.Ma Jun's reach found that the microcirculation could increasingly obstacles and the burn wound has been gradually deepened by seawater immersion,and provided theoretical reference for clinical treatment of the burn with seawater immersion.Clinical study and previous experimental results show that the vacuum sealing drainage can reduce tissue edema and improve the local blood supply.One important reason for wound deepening after burn is local tissue edema caused by blood fluid leakage.Edema is a result of tissue damage and also one important reasons of hinder wound healing.Tissue swelling make the cell gap increase which hinder the intercellular substance exchange.The local compression on micro vascular cause wound ischemia-hypoxia and impedes wound healing.Compression of local lymphatic makes the reflux disorder and aggravates the tissue edema.Negative pressure increases the drainage of wound exudates and avoids local infiltration liquid accumulation.Vacuum sealing drainage can reduce serum and edema fluid leaking to stasis zone and solidification zone of burn wound and thereby preventing the further deepening of burn wounds.Lv Xiaoxing's animal model of full-thickness skin defects of rabbit ears proved VSD technique can effectively reduce wound edema and blood vessel permeability.Morykwas MJ pointed out that fluid removal both decreases edema--thus decreasing interstitial pressure and shortening distances of diffusion--and removes soluble factors that may affect the healing process.Kamolz LP's clinical reachfound VSD treatment of limb drained a large amount of liquid and swelling subsided quickly.Local wound ischemia is one of the major problems that hinder wound healing?Because oxygen and other nutrients must through blood to transport to the wound,and toxic substances and metabolites are outputted from wound through blood too.Chen's experiment showed that negative pressure can significantly increase the wound blood flow perfusion by the laser doppler blood flow detection.Li Jing's reach on the rabbit ears skin wound model found that VSD treatment can significantly increase the number of capillaries,increase the wound capillary cross-sectional area,accelerate the blood circulation in the local wound,also can induce the recovery of endothelial cells so as to promote the recovery of damaged capillaries.It can stimulate new blood capillary sprouting and narrow the gap of endothelial cells.Angelica in the study of pigs found that in the negative pressure suction to several centimeters from the wound of capillary,blood flow increased,this change may make partial oxygen pressure increase so as to promote wound healing.Li Xueyong and other researchers believe that the interaction between VSD and the wound tissue after force each other can accelerate the wound blood circulation.This provides a mechanical effect explanation for VSD promotes wound blood circulation.Studies have found that,negative pressure drainage can not only improve the microcirculation blood flow velocity,but also can significantly increase the acute wound capillary density,increase nitric oxide synthesis,thus improve wound microcirculation blood supply,promote wound healing.Hypoxia and slightly acidic can stimulate vascular fibroblast proliferation,and increase wound blood flow.Animal experiments have found that after treatment of the vacuum sealing drainage,local wound vessel diameter increased,and blood vessel density increased,blood flow of negative pressure wound increased.Heparin is a kind of glycosaminoglycan(GAG),can play the anticoagulant effect in vivo and in vitro,which was extracted from the liver in 1916,and gradually applied to the treatment of burn patients.The mechanism of heparin anticoagulation and thrombolysis is through binding antithrombin and activating heparin cofactor,which can inactivate multiple coagulationfactor,generate anticoagulant activity.Hang Shouyun's method of using India ink perfusion of found that heparin can effectively improve the deep II degree wound microcirculation in guinea pigs.Clinical observation found that heparin on burn wound can accelerate the recovery of ischemic tissue blood supply.Vascular regeneration was found in 24 hours after using heparin.At the beginning,small red spots appear in the burned wound,then along with the increase of the number and density of red dot,vascular bed gradually formed and establish blood circulation,ischemia tissues were gradually replaced by granulation tissue?On the basis of these theoretical and experimental study,this study design the animal experiment,in which the closed negative pressure drainage and heparin solution techniques were applied to the treatment of scalded New Zealand white rabbits with seawater immersion.It may provide experimental reference by observing the pathological angiogenesis,wound healing time,water content and micro vessel count,and provides reference for the clinical treatment of burn wound with seawater immersion.ObjectiveTo investigate the effect of vacuum sealing drainage combined with heparin irrigation on wound pathological changes in scalded rabbits with seawater immersion?MethodsAnimal model:20 rabbits of cleaning grade(provided by the experimental animal center of Southern Medical University)weight 2.0kg-2.5kg,male or female(excluding pregnant rabbit rabbit),age 3-4 months.Injury and the experimental method:80 g/L sodium sulfide unhair rabbits' back 24 hours before scaled.3%sodium pentobarbital was injected from ear vein for anesthesia with the dosage of 30 mg/kg before scaled.Four 4cm*4cm size scaled wound were made by 36 layer gauze after 99? constant temperature water bath for 17s.Four 1%TBSA deep second degree burn wound(tissue pathology)were made in each experimental animal.3 wounds were treated with seawater immersion for 2 hours,1 wound was exposed in air for 2 hours.The exposed wound was dealed with common dressing(group a),the other three wound were divided into common dressing after seawater immersion(group b),vacuum sealing drainage after seawater immersion(group c),vacuum sealing drainage combined with heparin irrigation after seawater immersion(group d).Test index and Methods:Wounds welling and necrotic tissues were observed at 1,3,5,7d after scalded?Samples were selected from wounds and stained by HE and immunohistochemistry technique?The morphology and expression of VEGF and CD34 were detected under light microscope?The changes of endothelial cells in wound capillary were observed by electron microscopy.Wet and dry weight method was used to determine water content in wound tissues?Wound healing rate was calculated at day3,5,7,14 after scalded.Data processing:Statistical software of SPSS 13 was used for data analyze.Numerical data were expressed as the standard deviation of addition and subtraction(mean ± SD).The measurement data were analyzed using analysis of variance.Multiple comparisons using LSD method(variance not neat use Dunnett T3 method),P<0.05 was significant difference.Enumeration data were compared using the wilcoxon rank sum test.Results1.Gross observation:1 day after injury,all the wound were edema.Wound without immersion(group a)was dry,wound with seawater immersion(group b)deepened,wounds of negative pressure drainage group(group c and d)were humid.3 days after injury,the wound swelling had subsided.Group a and b had necrosis tissue attachment.Base in group c and d were fresh,rosy.5 days after injury,the wound surface encrusted in a group,necrotic tissue gradually dissolved in group b,wounds were fresh in group c and d.necrotic tissue of group d was less than that of group c.7 days after injury,a and b groups still had necrotic tissue attached,while most necrotic tissue had been cleared in c and d groups.2.Pathological observation:1 day after injury,epidermis necrosis,dermal edema,inflammatory cells infiltration,capillaries expansion can be observed in each groups'wound,especially in group b.3 days after injury,wounds of a and b group still edema,dermis necrotis deepened.Edema of c and d group were lighter than that of a and b group.5 days after injury,tissue edema significantly reduced in all groups.Group of a and b still have a large number of inflammatory cell infiltration,edema of collagen fibers with necrosis.7 days after injury,wound tissue edema of c and d group were obviously receded;new blood vessels were more visible.New blood vessels of group c and d were more intensive than group b.3.Electron microscope observation:In group a,red blood cells packed in vascular cavity,endothelial cells edema and was still intact,the cell gap widened,cavitations occurred in mitochondria,ribosomes were visible.In group b,basement membrane partly disappeared,red blood cells shrinked and deformated in the capillary lumen,endothelial gap increased obviously,boundary between cells was not distinct,part of the endothelial cell necrosis,part apoptosis,cytoplasm in remaining endothelial cells decreased significantly.In group c,capillary endothelial basement membrane was integrity,intercellular gaps broadened,connections between cells opened.Part of endothelial cells apoptosis,autophagy body was forming.In group d,capillary basement membrane was integrity,red blood cells was scattered in the cavity,endothelial cells is still intact,and chromatin gathered under the nuclear membrane,intercellular gaps broadened.4.Wound tissue water content:In each group,water content reached the peak 3 days after injury,and then decreased gradually.5 days after injury,it dropped to less than first days,but still higher than that of normal skin,group d was the lowest and group b was the highest,differences between the groups was statistically significant.5.Wound VEGF staining results:In group d VEGF expression rate were higher than that of other groups,there was statistically significant difference between these groups.6.Wound vascular density detection:the change of capillary density was similar to VEGF expression,positive signal mainly located in the cytoplasm.Each phase MVD in group d were the highest and group b were lowest.The difference between groups was statistically significant.Conclusion1.Seawater immersion can aggravate the damage of endothelial cells in rabbit scaled wound and make the microcirculation dysfunction more serious.2.Vacuum sealing drainage combined with heparin irrigation can relieve edema of scaled wound with seawater immersion,improve microcirculation,accelerate the removal of necrotic tissue,and promote the growth of new blood vessels?It is an effective method for the treatment of scaled wound after seawater immersion.