Effects of microRNA-206 and its target gene IGF-1 on sevoflurane-induced activation of hippocampal astrocytes in aged rats through the PI3K/AKT/CREB signaling pathway

The study aims to explore the effects of microRNA-206 (miR-206) targeting IGF-1 on the activation of hippocampal astrocytes in aged rats induced by sevoflurane through the PI3K/AKT/CREB signaling pathway. Wistar rats and astrocytes were divided into the normal/blank, sham/negative control (NC), sevoflurane (sevo), miR-206 mimics+sevo, miR-206 inhibitors+sevo, miR-206 NC+sevo, IGF-1 shRNA+sevo, and miR-206 inhibitors+IGF-1 shRNA+sevo groups. The Morris water maze test was exhibited to assess the cognitive functions. Glial fibrillary acidic protein (GFAP) expression was detected by immunofluorescence assay. Western blotting and RT-qPCR were used to detect the expression of miR-206, IGF-1, PI3K, AKT, CREB, pPI3K, pAKT, pCREB, cytochrome-c (Cyt-c), and caspase-3. Cell viability and apoptosis were detected by MTT assay and annexin V/PI double staining respectively. Mitochondrial transmembrane potential (MTP) were determined by flow cytometry. The IGF-1 shRNA+sevo group showed reduced miR-206 expression. Compared with the normal/blank group, the sevo, and miR-206 NC+sevo groups showed decreased miR-206 and GFAP expressions, cell viability and MTP but increased expressions of IGF-1, PI3K, AKT, CREB, pPI3K, pAKT, pCREB, Cyt-c and caspase-3, as well as cell apoptosis. Similar trends were observed in the miR-206 inhibitors+sevo group when compared with the sevo group. The study provides evidence that miR-206 alleviates the inhibition of activation of hippocampal astrocytes in aged rats induced by sevoflurane by targeting IGT-1 through suppressing the PI3K/AKT/CREB signaling pathway.