The Study Of Effect Of Escharectomy During Shock Stage On Cellular Immune Function In Severe Burned Rats

Objective:1.To investigate the effect of escharectomy en mass during shockstage on cellular immune function in rats with 30% TBSA(total body surfacearea)â…¢degree scald. 2. Then illustrate its probable mechanism in the immunedamage post-burn.Methods:In the experiment 70 healthy wistar rats(body weighting200±20g)were acclimatized for a period of one week. This population wassubdivided randomly into three categories:in group A escharectomy duringshock stage(in 6 hour postburn,n=30);in group B escharectectomy routinely(in 4 day postburn,n=30);in group C(control group)animals weren't subjectedto thermal injury and operation (n=10). The solution of 8% sodium sulfide wasused to epilate and nothing was given them to drink or to eat for 12 hours beforeexperiment. 5% Ketamine Hydrochloride(2ml/Kg)was given throughintraperitoneal injection then made it in ventral decubitus when it was perfectlyanesthetized. According to the formula S =K·W^2/3 (K=0.091;S=body surfacecm²; W= body weight gramme),calculate the area of 30% TBSA then adjustthe acreage of the sprayer of the scald apparatus delimit this area to be scalded onrats'back. With the other area protected properly the animal's back, rats was putinto 106℃,3MPa,for 8 second and which made â…¢degree scald(confirmed bythe pathology slice). Resuscitation was given included intraperitoneal lactatedRinger's solution injection according to Parkland Formula. Animals took foodfreely after waking. The group A were given escharectomy en mass at 6 hourpostburn. The wound were managed by iodoformand twice a day untilescharectomy en mass at 4 day postburn in group B. All animals were cut bladethickness and skin graft with during 20 minute. The radiated swine skinimpregnated with norfloxacin and silver grafts were transplanted on the woundsin groups A and B. Ten Animals were killed in 1,5 and 9 days postburnrespectively in group A and B. And four milliliters of blood were collected insterile K3 EDTA vacutainer tubes and spleen was harvested aseptically. BloodSamples were stained within 6 h and assayed within 24 h of collection. Theperipheral blood T-lymphocyte subsets,NK cells activity,the CD25 expressionof T-lymphocyte of peripheral blood and the splenic T-lymphocyte in vitrothrough Con A culture were assay by Flow Cytometry(FCM). Splenocytes wereisolated aseptically,and were diluted into 1～10×106 with RPMI 1640 solutionand were cultured 48 hours with Con A in culturing plate under 37℃including 5% CO2. The cells was separated by the centrifugal effect(1000r/min 5minute),and were diluted into 1～10×106 with PBS solution. The cells were stained withCD3 (PE)and CD25(FITC). The cells were analyzed by Flow Cytometry. Theexperimental data were handled by the software of SPSS 12.0. Results: Peripheral blood T-lymphocyte subsets:1.There was nosignificance diversity in CD3 among three groups(p>0.05). CD4 ,CD4 /CD8 + + + +ratio in rats with severe burn were significantly lower while CD8 greatly higher +than those in controlled group(P<0.01 or P<0.05). 2. CD4 ,CD4 /CD8 ratio + + +in rats with severely burned after escharectomy during burn shock stage weresignificantly higher while CD8 greatly lower than those in routine group at 5,9 +PBD(P<0.01 or P<0.05). 3.The immune index was improved in group A at 9PBD, there were no significance diversity in CD4 ,CD8 ratio than control group + +(p>0.05)but the CD4 /CD8 ratio not resume. + + NK cells activity: 1.NK cells activity in peripheral vein of Group A andGroup B is lower than Group C after burn injury with significant difference (P<0.01 or P<0.05);2. NK cells activity in peripheral vein of escharectomygroup in the shock stage increased obviously compared with the group receivingconventional therapy at 5,9 PBD with significant difference. And they approachto the normal level until day 9 PBD (p<0.05). The CD25 expression of T-lymphocyte of peripheral blood:1. The CD25expression of T-lymphocyte in rats with severe burn were significantly lowerthan those in controlled group (P<0.01 or P<0.05). 2. The CD25 expression ofT-lymphocyte of peripheral blood in rats with severely burned after escharectomyduring burn shock stage were significantly higher than those in routine group (p<0.01 or P<0.05). The CD25 expression of the splenic T-lymphocyte in vitro through Con Aculture: 1. The CD25 expression of T-lymphocyte in rats with severe burn weresignificantly lower than those in controlled group (P<0.01 or P<0.05). 2. TheCD25 expression of T-lymphocyte of the splenic T-lymphocyte in vitro throughCon A culture in rats with severely burned after escharectomy during burn shockstage were significantly higher than those in routine group(P<0.01 or P<0.05). Conclusion: The immunity was suppressed in the rats with severe burn. These data suggest that escharectomy during burn shock stage may bebeneficial in at immune suppressed by improving the T-lymphocyte subsets,NKcell,the CD25 expression of T-lymphocyte of peripheral blood and the splenicT-lymphocyte in vitro through Con A culture. Meanwhile it also keeps theorganism from immunosuppression. According to all of this, we hold thatescharectomy during shock stage will play an important roll in the clinicaltherapy of severe burn.