Effect Of Lyn Kinase On Acute Lung Injury(ALI) Mouse Model And Its Mechanism

Objective: To investigate the effect of Lyn kinase on acute lung injury(ALI)mouse model induced by lipopolysaccharide(LPS)and its mechanism.Methods: Ten transgenic C57 BL / 6J mice with high expression of Lyn were randomly divided into two groups:LPS group(LPS+ Lyn-TG group)and PBS group(PBS+Lyn-TG group).Ten wild-type C57 BL / 6J mice were equally divided into LPS group(LPS + WT group)and PBS group(PBS + WT group),with 5 mice in each group.All groups were anesthetized with intraperitoneal injection of pentobarbital sodium before intratracheal injection.The LPS + WT group and the LPS+ Lyn-TG group were injected with 5 μ g / g LPS(LPS dissolved in 50 μl PBS solution),and the other two groups were given the same volume of PBS(phosphate buffer solution).Four hours after LPS / PBS administration,all mice were killed and lung tissue and blood samples were collected.Part of the right lung tissue was weighed and the wet / dry ratio(W /D)was calculated,The middle lobe tissue was collected and frozen to make tissue homogenate,the right lower lobe was fixed with formaldehyde and used for HE staining for lung histopathological examination.The left lung was used for alveolar lavage to collect lavage fluid,and the total cell number of leukocytes was measured.The neutrophils were counted by HE staining method,and the protein concentration in alveolar lavage fluid and serum was measured to calculate lung permeability index(LPI).The content of IL-6,IL-8 and TNF-α in serum were detected by ELISA.The expressions of ZO-1,Occludin and β-Catenin were detected by immunofluorescence.The expression levels of CHOP,Bi P,caspase-3 and Bcl-2 were detected by Western blot.Results: The mice in PBS + WT group and PBS + Lyn-TG group treated with PBS showed complete lung tissue structure,no destruction of alveolar wall,no widening of alveolar septum,and there was no inflammatory cell infiltration.Compared with PBS+WT group,LPS+ WT group showed obvious pathological damage in lung tissue,there were discontinuous structure of alveolar wall,obvious destruction,interstitial edema,intra alveolar hemorrhage and septal thickening,but the above changes were significantly alleviated in LPS+Lyn-TG group.Compared with PBS + WT group,the number of inflammatory cells of BALF in LPS+WT group and LPS+Lyn-TG group increased significantly(P < 0.001),and the change in LPS+WT group was more obvious than that in LPS+Lyn-TG group(P < 0.001),while the number of inflammatory cells in LPS+WT group was close to that in PBS + WT group(P > 0.05).After LPS treatment,W / D and LPI of the WT+LPS group mice were higher than those of mice with high expression of Lyn kinase(P < 0.001).Compared with the results of ELISA,the content of IL-6,IL-8 and TNF-α in PBS + WT group and PBS + Lyn-TG group were close(P > 0.05),while compared with PBS +WT group,the contents of LPS + WT group and LPS + Lyn-TG group were significantly increased(P < 0.05),and the content of LPS + Lyn-TG group was lower than that of LPS+WT group(P < 0.05).Compared with PBS + WT group,the fluorescence intensity of ZO-1,occludin and β-Catenin in LPS + WT group and LPS + Lyn-TG group all decreased,and the LPS + WT group was weaker than that of LPS + Lyn-TG group,but there was no significant difference between PBS + Lyn-TG group and PBS + WT group.Compared with PBS + WT group and PBS + Lyn-TG group,the expression levels of CHOP,BIP and Caspase-3 in LPS+WT group and LPS + Lyn-TG group were all increased,on the contrary,the expression level of Bcl-2 was decreased,and the change of LPS + WT group was more significant than that of LPS + Lyn-TG group(P < 0.05),which suggested that endoplasmic reticulum stress and apoptosis are more obvious.Conclusion:1.Lyn kinase can reduce the damage of lung tissue structure,inflammatory exudation and tight junction protein degradation induced by LPS in mice,and play a protective effect on acute lung injury.2.The level of endoplasmic reticulum stress in LPS induced ALI / ARDS mice increased significantly.3.Lyn kinase can reduce endoplasmic reticulum stress in LPS induced ALI/ ARDS mice.4.Lyn kinase can protect LPS induced ALI / ARDS through its anti-inflammatory effect,which may be regulated by a new mechanism related to endoplasmic reticulum stress..