Effects of IL-8 and IL-10 in mediating lipopolysaccharide-induced acute lung injury in rabbits

Objective To study the mechanism of acute lung injury(ALI) induced by lipopolysaccharide(LPS)in rabbits. Methods The model was produced by intravenous injection of 3 μg/kg LPS and at 24 hours followed by infusion of 50 μg/kg LPS for 2 hours.When pulmonary dynamic compliance (Cdyn) decreased to 75% of the baseline level, rabbits were randomly divided into two groups:treatment group and controls. Each group had 8 animals, treatment group was receired dexamethasone 1mg/kg intravenously, while control group was receired 0.2 ml/kg 0.9% sodium chloride. Plasma interleukin-8 (IL-8) and interleukin-10 (IL-10) levels were measured. 6 hours after administration of dexamethasone, the animals were killed. Lung tissue and bronchoalveolar lavage fluid (BALF) were collected for measurement of IL-8 and IL-10,and amount of PMN in BALF. In addition,lung tissue was also used for histological examination. Results The levels of IL-8 and IL-10 were significantly higher at the time of 75% Cdyn than those at the baseline in both groups(P0.05).The levels of IL-8 in plasma,lung tissue,BALF in treatment group significantly decreased(P0.05).The ratios of IL-8 to IL-10 in lung tissue and BALF in treatment group were significantly lower than those in control group(P0.05). In addition, the injury and inflammatory cellular infiltration in the pulmonary stroma and alveoli in C group were much severe than those in T group. Conclusion IL-8 and IL-10 may play a role in the development of LPS-induced ALI. 1 mg/kg dexamethasone early administered could reduce LPS-induced ALI in rabbits,which might be related to IL-8 decrease.