Therapeutic effect of ulinastatin combined with dexamethasone on blast-induced acute lung injury in rabbits

Objective To discuss the therapeutic effect of ulinastatin combined with dexamethasone on blast-induced acute lung injury (ALI) in rabbits. Methods Thirty-eight New Zealand white rabbits with blast-induced ALI were divided into four groups according to the random number table: injury group (n=8), treatment group Ⅰ (dexamethasone alone, n=10), treatment group Ⅱ (ulinastatin alone, n=10), combination therapy group (dexamethasone+ ulinastatin, n=10). In addition, 8 uninjured rabbits were randomly selected as control group. Treatment groups were given relevant medication by intramuscular injection at 0.5, 12, 24, 36 and 48 hours after successful modeling. Injury group and control group were given equal volume of isotonic saline at the same time. Parameters of respiratory rate, oxygenation index (PaO2/FiO2), TNF-α, IL-6, IL-8 and neutrophil elastase (NE) were detected before and afterfirst treatment at 6, 24, 48 and 72 hours. All rabbits were sacrificed after 72 hours to detect TNF-α, IL-6, IL-8 and NE contents in bronchoalveolar lavage fluid (BALF) and to measure wet to dry lung weight ratio. HE staining was performed to observe pathological changes of lung tissues. Results In contrast, respiratory rate was high in injury group at each time point, which increased to the peak (75.0±7.4)times/min at 6 hours far higher than (33.0±4.5)times/min in control group (P <0.01). Wet to dry lung weight ratio and TNF-α, IL-6 as well as IL-8 contents of the peripheral blood and BALF in injury group were significantly higher than those in control group (P <0.01). PaO2/FiO2 in injury group was decreased to the lowest level of (180.5±12.6)mmHg at 72 hours far lower than (403.7±8.0)mmHg in control group (P<0.01). While improvements were observed in treatment groups with respect to these indicators, and significantly much better results were detected in combination therapy group rather than in treatment groups Ⅰ and Ⅱ(P<0.01). Conclusion Ulinastatin combined with dexamethasone is an effective therapy on blast-induced ALI in rabbits, and the effect is significantly better than that with single use of ulinastatin or dexamethasone. Key words: Blast injuries; Acute lung injury; Dexamethasone; Ulinastatin