OBJECTIVETo observe and study the effects of sivelestat on acute lung injury in dogs with severe burn-blast combined injury.

METHODSThirty-two male beagle dogs of clean grade were divided into 4 groups: uninjured group (U), combined injury control group (CIC), combined injury+low dose of sivelestat group (CI+LS), combined injury+high dose of sivelestat group (CI+HS), with 8 dogs in each group. Except for the dogs in group U which were not injured, the dogs in the other 3 groups were inflicted with severe burn-blast combined injury. According to the Parkland formula, the dogs in groups U and CIC were infused with physiological saline, and the dogs in groups CI+LS and CI+HS received sivelestat with the dosage of 0.5 and 2.0 mg·kg(-1)·h(-1) respectively in addition. The 24 h continuous intravenous infusion was carried out for 2 days. At post injury hour (PIH) 6, CT scanning was conducted to observe the lung damage. At PIH 2, 6, 12, 24, and 48, mean arterial pressure (MAP), respiratory rate (RR), extra vascular lung water (EVLW), pulmonary vascular permeability index (PVPI), PaO2, and PaCO2 were measured; the contents of neutrophil elastase (NE), IL-8, and TNF-α were determined by ELISA. At PIH 48, all the dogs were sacrificed, and the lung tissues were harvested to measure the wet to dry lung weight ratio. The same examination was carried out in the dogs of the group U at the same time points. Data were processed with analysis of variance of repeated measurement and LSD test.

RESULTS(1) CT images showed some exudative lesions in the dogs of groups CIC and CI+LS but not in the dogs of groups U and CI+HS. (2) No statistically significant differences were observed in MAP at each time point between every two groups (with P values above 0.05). The RR values in group U were significantly different from those of the other 3 groups at all time points (with P values below 0.05). The values of EVLW and PVPI in 3 combined injury groups were significantly different from those in group U at PIH 6, 12, 24, and 48 (with P values below 0.05). The values of RR and EVLW in group CI+LS were significantly different from those in group CI+HS at PIH 12, 24, and 48 (with P values below 0.05). The values of PVPI in group CI+LS were significantly different from those in group CI+HS at PIH 24 and 48 (with P values below 0.05). (3) The levels of PaO2 and PaCO2 showed significant differences between group U and the other 3 groups at each time point (with P values below 0.05). The levels of PaO2 in group CI+LS were significantly different from those in CI+HS group at PIH 12, 24, and 48 (with P values below 0.05). The level of PaCO2 showed significant differences between group CI+LS and group CI+HS at PIH 24 and 48 (with P values below 0.05). (4) The contents of NE (except for PIH 2), TNF-α, and IL-8 showed significant differences between group U and the other 3 groups at each time point (P < 0.05 or P < 0.01). At PIH 2, 6, 12, 24, and 48, the contents of NE in groups U, CIC, CI+LS, and CI+HS were respectively (69 ± 21), (83 ± 24), (80 ± 20), (75 ± 17), (72 ± 27) pg/mL; (66 ± 24), (196 ± 20), (231 ± 26), (252 ± 25), (266 ± 22) pg/mL ; (71 ± 22), (180 ± 27), (214 ± 21), (194 ± 24), (218 ± 20) pg/mL; (68 ± 22), (136 ± 24), (153 ± 22), (146 ± 26), (150 ± 28) pg/mL. NE values in group CI+HS were statistically different from those in groups CIC and CI+LS at PIH 6, 12, 24, and 48 (with P values below 0.05). The contents of TNF-α in group CI+LS were statistically different from those in groups CIC and CI+HS at PIH 24 and 48 (with P values below 0.05). The contents of IL-8 in group CI+LS were statistically different from those in group CI+HS at PIH 24 and 48 (with P values below 0.05). (5) At PIH 48, the wet to dry lung weight ratio of group CIC was statistically different from that in group CI+LS or group CI+HS (with P values below 0.05); there was also difference between group CI+LS and group CI+HS (P < 0.05).

CONCLUSIONSSivelestat, especially in a high dose, exerts a protective effect in acute lung injury after burn-blast combined injury through improving the index of blood gas analysis, ameliorating pulmonary edema, and lowering the production of pro-inflammatory mediators.