Effects of insulin on alveolar fluid clearance in lipopolysaccaride-induced acute lung injury rats

AIM To investigate the effects of insulin on alveolar fluid clearance(AFC)in lipopoly-sacccharide(LPS)-induced acute lung injury(ALI)rats.METHODS Thirty-six Sprague-Dawley rats were randomly divided into three groups,with 12 rats in each group.The rats in the model group and treatment group were received LPS at a dose of 5 mg·kg-1 to establish ALI model.One hour later,insulin was administrated at a dose of 0.1 U·kg-1·h-1 by micro-osmotic pump in the treatment group for 8 hours.Normal saline was administrated at a dose of 1 mL·kg-1 by micro-osmotic pump in the normal group and control group for 8 hours.The pathological changes in lung,lung wet/dry weight ratio and AFC were observed.The expressions of alveolar epithelial sodium channel(ENaC)were measured by immunocytochemistry and Western blot.RESULTS The blood glucose level in the treatment group showed no significant difference compared with that in the model group(P 0.05).Compared with the control group,lung wet/dry weight ratio was higher in the model group(P 0.05),while arterial partial pressure of oxygen,AFC and the expressions of α-,β-and γ-ENaC were lower(P 0.05).The lung injury was alleviated in the treatment group.Compared with the model group,lung wet/dry weight ratio was lower in the treatment group,while arterial partial pressure of oxygen,AFC and the expressions of α-,β-and γ-ENaC were higher(P 0.05).CONCLUSION Insulin can promote AFC and alleviate pulmonary edema in LPS-induced ALI rats,which is possibly achieved by up-regulation of the expressions of α-,β-and γ-ENaC.