[Protective effect of lytic cocktail (inhibition of stress) on lung injury in severe burn rat].

OBJECTIVE: To investigate the protective effect of inhibition of stress (lytic cocktail) on lung injury in severe burn rats at early stage. METHODS: Sprague-Dawley rats inflicted with 30% TBSA full-thickness burn were randomly divided into A group (n = 36, fluid resuscitation with administration of lytic cocktail), B group (n = 36, fluid resuscitation only). Lung function was evaluated by partial pressure of oxygen (PaO2) in arterial blood and histopathologic changes on 3, 5, 7, 10 post burn day (PBD). The levels of malonyldialdehyde (MDA), myeloperoxidase (MPO), tumor necrosis factor-alpha(TNF-alpha) and interferon-gamma (IFN-gamma) in lung tissue were measured at the same time points. RESULTS: The PaO2 level in A group on 3 PBD (12.58 +/- 0.41 kPa) was significantly higher than that in B group (8.86 +/- 0.23 kPa, P < 0.01). Compared with those in B group, the levels of MDA and MPO were significantly decreased in A group at each time point (P < 0.05 or 0.01), the levels of TNF-alpha on 3, 5, 7 PBD (P < 0.05 or 0.01) and IFN-gamma on 5, 7, 14 PBD (P < 0.01) were also decreased in A group. Swollen lung mesenchyme was alleviated, infiltration of inflammatory cell was lessened in A group. CONCLUSION: Lytic cocktail combined with immediate fluid resuscitation can inhibit stess response, downregulate the expression of inflammatory factor, ameliorate lung function in severe burn rat at early stage.

[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.