The Protective Effect Of Mesenchymal Stem Cells(MSCs) On Type Ⅱ Alveolar Epithelial Cells Damage In Sepsis By Transferring MiR-223

Objective:This research adopts the Lipopolysaccharide(LPS)stimulation type Ⅱ alveolar epithelial cells(AECⅡ)model to simulate the sepsis lung injury.To explore the relationship between miR-223,inflammatory body-3(NLRP-3)and sepsis l ung injury.It was confirmed that mesenchymal stem cells may reduce the infla mmatory response of sepsis type II alveolar epithelial cells(AECⅡ)by transferring miR-223 and inhibiting the expression of NLRP-3.Methods:After the establishment of sepsis induced alveolar epithelial injury model,it is divided into: control group,LPS stimulates AEC;PCR detection of miR-223,NLRP-3expression and inflammatory factors levels.At the same time,miR-223 agonists and inhibitors were transfected into AECⅡ and the changes of these factors were detected after LPS treatment.The target NLRP-3 was determined by gene target protein prediction and then by a two-way luciferase experiment.To further explore the relationship between NLRP-3and AECⅡ injury,the experimental groups were: blank control group,si NLRP-3,and si NC blank group.The expression of inflammatory factors was detected after LPS stimulation.Mesenchymal stem cells were transfected with miR-223 agonist and inhibitor,and the experiment was divided into five groups: control group,AEC group,AEC+MSC group,AEC+MSCmiR-223 agonist and AEC+MSCmiR-223 inhibitor group.The expression of inflammatory factors and NLRP-3 were detected.Result:(1)After treatment with different concentrations of LPS,the miR-223 and NLRP-3expression levels of each group were statistically significant compared with the blank group at P<0.05.In the miR-223 agonist transfected group,the expression level of NLRP-3 and the level of inflammatory factors were P<0.05 compared with the groups,and the difference was statistically significant.(2)Target gene prediction and two-way luciferase experiments have shown that miR-223 can target and regulate the expression of NLRP-3..And after interfering with the expression of NLRP-3,the levels of inflammatory factors were significantly lower than those in each group,and the difference of P<0.05 was statistically significant.(3)The mesenchymal stem cells were co-cultured with the modeled alveolar epithelial cells,and the expressions of miR-223 and NLRP-3 were detected by PCR,and the expression of NLRP-3 was detected by Wester Blot.The results showed that the expression of miR-223 and NLRP-3 in the MSCs and AEC co-culture group was significantly different from that in the AEC group P<0.05,which was statistically significant.Conclusion:(1)miRNA-223 and NLRP-3 are related to the occurrence of sepsis-related lung injury,and miR-223 can inhibit the production of inflammatory factors by targeting the expression of NLRP-3.(2)Mesenchymal stem cells may reduce the inflammatory damage of type Ⅱ alveolar epithelium by sepsis via transferring miR-223 and inhibiting the expression of NLRP-3.