Clearance effect of regulation of serine/threonine protein kinase-1 signaling pathway by insulin on pulmonary edema in mice with acute lung injury / 中国生物制品学杂志

ABSTRACT

@#Objective To investigate the mechanism of insulin alleviating pulmonary edema in mice with acute lung injury(ALI) by serine/threonine protein kinase-1(SGK1).Methods 32 male adult C3H/HeN mice were randomly divided into control group(only pumped with the same amount of normal saline as the treatment group),ALI group(continuously pumped with the same amount of normal saline as the treatment group after modeling),treatment group [continuously pumped with 0.1 U/(kg·h) of insulin through jugular vein after establishing ALI model] and SGK1 siRNA group[continuously pumped with 0.1 U/(kg·h) of insulin and given SGK1 siRNA(75 μg SGK1 siRNA diluted in 100 μL saline) simultaneously after establishing ALI model] with 8 mice in each group.After 8 h,the mice were killed for arterial blood gas analysis(1 h after establishment of the model) and the changes of plasma glucose levels were detected(0,1,4and 8 h);The bronchoalveolar lavage fluid(BALF) was collected to detect the content of total protein,and the alveolar epithelial permeability and lung water content were measured;The pathological changes of lung tissue and apoptosis of lung epithelial cells were observed;The protein expressions of alveolar epithelial sodium channel(ENaC) and α_1-Na~+,K~+-ATPase and the phosphorylation level of SGK1 were determined by Western blot.Results There was no significant difference in plasma glucose level of ALI and treatment group at 0,1,4 and 8 h after insulin infusion(t=1.330 0,0.986 0,0.565 7 and 0.724 3,P=0.204 7,0.340 7,0.580 6 and 0.480 8,respectively).Compared with ALI group,the partial pressure of oxygen in arterial blood in treatment group increased significantly(t=6.026,P <0.000 1),while the BALF protein content,alveolar epithelial permeability,lung water content and lung epithelial cells apoptosis decreased significantly(t=7.39,5.286,5.651 and 3.312,P <0.000 1,=0.000 4,=0.000 2 and=0.007 8,respectively),and the expression of α-ENaC and α_1-Na~+,K~+-ATPase and the phosphorylation level of SGK1 in lung tissue significantly increased(t=26,18.67 and 8.547,P <0.000 1,<0.000 1 and=0.000 1,respectively);Compared with the treatment group,the BALF protein content,alveolar epithelial permeability,lung water content and lung epithelial cells apoptosis increased significantly in SGK1 siRNA group(t=5.964,3.449,3.148 and 3.520,P=0.000 2,0.006 2,0.010 4 and0.016 9,respectively),while α-ENaC and α_1-Na~+,K~+-ATPase protein expression and SGK1 phosphorylation level decreased significantly(t=13,9.874 and 7.741,P <0.000 1,<0.000 1 and=0.001 5,respectively).Conclusion Exogenous insulin can alleviate the pulmonary edema in ALI mice,which might be mediated via up-regulation of the expressions of α-ENaC and α_1-Na~+,K~+-ATPase by SGK1.