Protective Effects Of Anti-rat IL-6R Monoclonal Antibody On Apoptosis Of Alveolar Type Ⅱ Epithelial Cells Induced By Lipopolysaccharide In Adult Rats In Vitro

Objective:To investigate the protective effects of Anti-rat IL-6R monoclonal antibody on apoptosis of alveolar typeⅡepithelial cells through the establishment of apoptosis model of alveolar typeⅡepithelial cells induced by lipopolysaccharide(LPS) in adult rats in vitro.Methods: Alveolar typeⅡepithelial cells which were isolated, purified and identified by electron microscopy from adult rats were cultured in 24-well culture plates (1×106cells/well). After primary culture for 23 hours, they were divided into 5 groups (4 well each group): Group A (control group): DMEM only ; Group B(LPS injury group): DMEM + LPS 10μg/ml; Group C: DMEM + LPS 10μg/ml + Anti-rat IL-6R monoclonal antibody 5μg/ml; Group D: DMEM + LPS10μg/ml + Anti-rat IL-6R monoclonal antibody 10μg/ml; Group F: DMEM + LPS10μg/ml + Anti-rat IL-6R monoclonal antibody 20μg/ml. After culture for 48 hours, the apoptosis rate of alveolar typeⅡepithelial cells were detected by flow cytometry (FCM) and concentrations of IL-6 and TNF-αin alveolar typeⅡepithelial cells culture supernatant were measured with enzyme linked immunosorbent assay (ELISA) .Results: Flow cytometry results showed that the apoptosis rate of alveolar typeⅡepithelial cells in group B, group C, group D and group E was obviously higher compared with group A and the apoptosis rate of alveolar typeⅡepithelial cells in group C, group D and group E was obviously lower compared with group B, the differences were statistically significant (P<0.05),which indicated that Anti-rat IL-6R monoclonal antibody had protective effects on apoptosis of alveolar typeⅡepithelial cells induced by lipopolysaccharide. This study also analyzed the concentrations of IL-6 and TNF-αin alveolar typeⅡepithelial cells culture supernatant and found that concentrations of IL-6 and TNF-αin group B, group C, group D and group E were obviously higher compared with group A, the difference was statistically significant (P<0.05). Concentrations of IL-6 and TNF-αin group C, group D and group E had no significant difference compared with group B (P>0.05).And there was also no significant difference among group C, group D and group E in concentrations of IL-6 and TNF-α(P>0.05).Conclusion: (1) LPS can induce apoptosis of alveolar typeⅡepithelial cells and stimulate secretion of IL-6 and TNF-αof alveolar typeⅡepithelial cells in adult rats in vitro; (2) Anti-rat IL-6R monoclonal antibody have protective effects on apoptosis of adult rat alveolar typeⅡepithelial cells induced by lipopolysaccharide in a concentration-dependent manner, but its exact mechanism remains to be further researched; (3) Anti-rat IL-6R monoclonal antibody have no significant effect on secretion of IL-6 and TNF-αof alveolar typeⅡepithelial cells.