Long non-coding RNA MEG3 alleviates postoperative cognitive dysfunction by suppressing inflammatory response and oxidative stress via has-miR-106a-5p/SIRT3

Postoperative cognitive dysfunction (POCD), a neurological complication after surgery, is common among the elderly in particular. Maternal expression gene 3 (MEG3) is a novel long non-coding RNA (lncRNA) that contributes to glial cell activation and inflammation. We aim to further explore its role in POCD. Mice were induced with sevoflurane anesthesia and underwent orthopedic surgery to establish a POCD model. BV-2 microglia activation was induced by lipopolysaccharide. The overexpressed lentiviral plasmid lv-MEG3 and its control were injected into mice. pcDNA3.1-MEG3, has-miR-106a-5p mimic, and its negative control were transfected into BV-2 cells. The expressions of has-miR-106a-5p MEG3 and Sirtuin 3 (SIRT3) in rat hippocampus and BV-2 cells were quantitatively detected. Levels of SIRT3, TNF-α, and IL-1β were detected by western blot, levels of TNF-α and IL-1β by ELISA, and expression of GSH-Px, SOD, and MDA by kits. The targeting relationship between MEG3 and has-miR-106a-5p was confirmed using bioinformatics and dual-luciferase reporter assay. LncRNA MEG3 was down-regulated in POCD mice, whereas has-miR-106a-5 levels were up-regulated. Overexpression of MEG3 could attenuate cognitive dysfunction and inflammatory response in POCD mice, inhibit lipopolysaccharide-induced inflammatory response and oxidative stress in BV-2 cells, and promote has-miR-106a through competitive binding with has-miR-106a-5-5 expression of target gene SIRT3. Overexpression of has-miR-106a-5p had a reverse effect on overexpression of MEG3 functioning on lipopolysaccharide-induced BV-2 cells. LncRNA MEG3 could inhibit the inflammatory response and oxidative stress via has-miR-106a-5p/SIRT3, thereby reducing POCD, which might be a potential biological target for the diagnosis and treatment of clinical POCD.