[miR-153 aggravates lung injury induced by lipopolysaccharide via inhibiting activated protein C (APC) in rats with sepsis and its mechanism].

Objective To investigate the mechanism of miR-153 targeting activated protein C (APC) to regulate lipopolysaccharide (LPS)-induced lung injury in rats with sepsis. Methods Female SD rats were divided into control group, LPS group, LPS combined with miR-153 inhibitor (miR-153 inhibitor) group, LPS combined with miR-153 inhibitor negative control (inhibitor NC) group, LPS and miR-153 inhibitor combined with APC small interfering RNA (si-APC) group, LPS and miR-153 inhibitor combined with APC small interfering RNA negative control (si-NC) group. Except for the control group, the other groups were given corresponding treatments, and then LPS were given to establish rat sepsis injury models. Real-time quantitative PCR was used to detect the expression of miR-153 and Western blot analysis to detect the protein expression of APC, B-cell lymphoma 2 (Bcl2) and cleaved caspase-3 (c-caspase-3). The rat alveolar epithelial cells were isolated and cultured, and their cell viability was detected by CCK-8 assay, along with cell apoptosis detected by flow cytometry. ELISA was performed to test the expression levels of superoxide dismutase (SOD), malondialdehyde (MDA), interleukin 6 (IL-6), IL-1β and tumor necrosis factor α (TNF-α) in rat serum; and the dual fluorescein reporter experiment detects the relationship between miR-153 and APC. Results Compared with the control group, rat model of sepsis lung injury showed significantly increased expression of miR-153 and reduced APC. The cell viability, Bcl2 protein expression and SOD activity of the LPS group were significantly reduced, and the apoptosis rate, c-caspase-3 protein expression, MDA, IL-6, IL-1β, and TNF-α content significantly escalated. Compared with the LPS combined with inhibitor NC group, the cell viability, Bcl2 protein expression and SOD activity of the LPS combined miR-153 inhibitor group significantly increased, while the apoptosis rate, c-caspase-3 protein expression, the content of MDA, IL-6, IL-1β and TNF-α dropped considerably. miR-153 can target and regulate the expression of APC. Compared with the LPS and miR-153 inhibitor combined with si-NC group, the cell viability, Bcl2 protein expression and SOD activity of the LPS and miR-153 inhibitor combined with si-APC group significantly down-regulated, and the apoptosis rate, c-caspase-3 protein expression, MDA, IL-6, IL-1β, and TNF-α contents increased significantly. Conclusion LPS induces increased expression of miR-153 in lung tissue, inhibits APC expression, promotes apoptosis, oxidative stress and inflammatory response in lung tissue of septic rats, and aggravates damage.