The Regulation Of Glycogen Synthase Kinase-3β During Treatment Of Mesenchymal Stem Cells In Acute Lung Injury In Rat

BACKGROUND:Acute lung injury(ALI)is a one of severe manifestation and remains a major cause of morbidity and mortality in critically ill patients.However,protective mechanical ventilation is a current treatment of ALI that provides essential life support of critically ill patients,it leads to exacerbate lung functional and structural alterations.Mesenchymal stem cell(MSCs)based therapy is a promising and novel treatment,it has been considered to be a potential treatment of acute lung injury;however,the mechanism involved are barely understood.Glycogen synthase kinase-3β(GSK-3β)has been associated with the pathogenesis of several diseases.We hypothesized that,glycogen synthase kinase-3p(GSK-3β)may represent potential therapeutic targets in acute lung injury.In the current study,we were focused on the possible enhancement,the contributing factor of MSCs therapy,what improves the outcome of cell treatment,thus we explored the role of inhibition of GSK-3p with a selective inhibitor of LiCl during treatment of MSCs in the acute lung injury,in vivo.METHODS:Experiments were carried out on 40 adults,Sprague-Dawley(SD)rats,those were randomly classified into 4 groups:1.Control group(treated with normal saline(NS)5 mg/kg),n = 10.2.Acute lung injury(ALI)group(treated with lypopolysaccharide(LPS)15 mg/kg),n = 10.3.ALI+ MSCs group(treated with MSCs via tail vein,after LPS administration 2 h)n = 10.4.ALI+ MSCs + Lithium chloride(LiCl)group(treated with MSCs and LiCl 20 mg/kg after LPS administration 2 h).LiCl was injected at every 24 hours to maintain blood concentration during the experiment.The blood serum was collected at 12 h of the study to determine the concentration of inflammatory cytokines by ELISA.The lung tissues were harvested on the 7th of the study to determine gene expression of surfactant protein-A,C(SP-A,C)for demonstrating an alveolar epithelial type Ⅱ cell’s alteration,and gene expression of β-catenin,GSK-3β for demonstrating regulation of Wnt/β-catenin signaling by RT-PCR.β-catenin protein level and lung histological changes were determined on the 7th and 14th day of study by WB assay,Hemotoxylin&Eosin and Masson’s trichrome staining,respectively.Finally,the mean area percentage of collagen fibers were measured by morphometric analysis.RESULTS:The results were revealed that intravenous transplantation of MSCs supplemented with inhibition of GSK-3β(LiCl)treatment group was determined more efficiency suppressed inflammatory cytokines in blood serum and expression level of SP-C mRNA was significantly higher in lung tissue after LPS administration.Moreover,inflammatory cell infiltration,pulmonary edema,pathological impairment,collagen depositions were revealed dramatically low in lung sections on the 7th day of study compared with the MSCs alone treatment group.The protein level of β-catenin,irregular cell proliferation and collagen deposions were determined higher in lung tissue on the 14th day of study compared to the 7th day.CONCLUSIONS:In the present study suggested that inhibition of GSK-3β likely to play a facilitating role to improve outcome of MSCs treatment in early stage(<7 days)of acute lung injury in vivo.But excessive inhibition of GSK-3β may lead to aberrant activation of β-catenin,which contribute fibrosis phase(>14 days)of acute lung injury and accelerate irregular cell proliferation.