Dexmedetomidine attenuates the neuroinflammation and cognitive dysfunction in aged mice by targeting the SNHG14/miR‑340/NF‑κB axis

Neuroinflammation plays a key role in the pathogenesis of postoperative cognitive dysfunction (POCD). Results of our previous study demonstrated that dexmedetomidine (Dex) attenuates neuroinflammation in BV2 cells treated with lipopolysaccharide (LPS) by targeting the microRNA (miR)-340/NF-κB axis. However, the molecular mechanisms by which Dex improves POCD remain unclear. In the present study, the association between long non-coding (lnc)RNA small nucleolar RNA host gene 14 (SNHG14) and miR-340 in BV2 microglial cells was determined using a dual-luciferase reporter assay. In addition, SNHG14, miR-340 and NF-κB expression levels were measured in LPS-treated BV-2 cells and hippocampal tissues of mice with POCD, and an enzyme-linked immunosorbent assay was used to determine the levels of proinflammatory mediators. Results of the present study demonstrated that SNHG14 exhibited potential as a target of miR-340. In addition, SNHG14 knockdown increased the levels of miR-340 and reduced the levels of NF-κB in LPS-treated BV2 cells. In addition, Dex treatment significantly reduced the levels of SNHG14 and NF-κB, and elevated the levels of miR-340 in the hippocampus of aged mice with POCD. Moreover, Dex treatment notably decreased the expression levels of TNF-α, IL-1β, IL-2, IL-6, IL-8 and IL-12 in the hippocampus of aged mice with POCD by upregulating miR-340. The spatial memory impairments in aged mice with POCD were also notably increased following Dex treatment via upregulation of miR-340. Collectively, results of the present study demonstrated that Dex may protect microglia from LPS-induced neuroinflammation in vitro and attenuate hippocampal neuroinflammation in aged mice with POCD in vivo via the SNHG14/miR-340/NF-κB axis. The present study may provide further insights into the mechanisms underlying Dex in the treatment of POCD.