抑制应激反应措施对严重烧伤大鼠早期创面侵袭性感染的影响

目的　观察严重烧伤大鼠早期创面遭受侵袭性感染后,抑制应激反应措施对大鼠生存率、脏器损害及其辅助性T淋巴细胞(Th)1 /Th2细胞因子格局的影响。　方法　建立30%TBSAⅢ度烧伤大鼠模型,随机分为对照组(未用冬眠合剂)和冬眠合剂组,每组36只。两组大鼠背部痂下注射1×108 集落形成单位(CFU) /ml铜绿假单胞菌菌液0. 1ml,观察两组大鼠痂下组织细菌定量、注射细菌后96h的生存率、脏器损害情况及白细胞介素(IL)2、IL 4、IL 10、γ型干扰素(IFN γ)的mRNA表达水平。　结果　两组大鼠痂下注菌后5h每克组织细菌数量>1×105 个,两组比较,差异有统计学意义(P<0. 01).冬眠合剂组大鼠生存率(66. 7±2. 6)%,明显高于对照组( 33. 3±1. 7 )% (P<0.01).冬眠合剂组大鼠脏器炎性细胞浸润和病理损害程度较对照组轻。冬眠合剂组注射细菌后即时(0h)IL 2mRNA表达水平低于对照组(P<0. 01),但注射细菌后48、96h其表达增强,对照组表达减弱(P<0. 05);对照组IFN γmRNA的表达水平低于冬眠合剂组(P<0. 01);冬眠合剂组IL 4、IL 10mRNA表达水平低于对照组(P<0. 05或0. 01)。　结论　抑制大鼠严重烧伤后早期应激反应水平对创面细菌的侵袭有保护作用,这一保护作用可能与抑制应激反应水平的同时Th1 /Th2细胞因子格局发生改变有关。

Influence of stress inhibition on invasive infection in burn wound during early postburn stage in severely burned rats

OBJECTIVE: To investigate the influence of inhibition of stress on the survival rate, organ dysfunction and (Th)1/Th2 cytokine profiles of the rats with invasive infection in the wound at early postburn stage. METHODS: Sprague-Dawley rats inflicted with 30% TBSA full thickness burn were randomly divided into A (n = 36, with immediate resuscitation), B (n = 36, with immediate resuscitation and lytic cocktail administration). After subeschar injection of 0.1 ml Pseudomonas aeruginosa (10(8) CFU/ml) on 3rd postburn day, the subeschar bacterial quantitative analysis, the survival rate at 96 hours after bacteria injection, the parameters of organ dysfunction and the mRNA expression of IL-2, IL-4, IL-10 and IFN-gamma were determined by corresponding methods. RESULTS: The quantity of subeschar bacteria was larger than 1 x 10(5)/gram in both groups. The survival rate in B group (66.7 +/- 2.6)% was obviously higher than that in A group (33.3 +/- 1.7)%, (P < 0.01). Inflammatory infiltration and pathological changes in the internal organs in B group were alleviated obviously compared with A group. The expression of IL-2 mRNA in B group was significantly lower than that in A group before bacterial inoculation, but increased at 48 and 96 hours after bacterial inoculation, while it was lowered in A group at the same time points (P < 0.05). The expression of IFN-gamma mRNA in A group was significantly lower than that in B group (P < 0.01), while that of IL-4 and IL-10 mRNA in A group was evidently higher than that in B group (P < 0.05 approximately 0.01). CONCLUSION: Inhibition of the stress response during early postburn stage could be beneficial to the prevention of the bacterial invasion due to the changes in Th1/Th2 ratio.