Activation of mitochondria apoptotic pathway is involved in the sevoflurane-induced hippocampal neuronal HT22 cells toxicity through miR-145/Binp3 axis.

Sevoflurane is a commonly used inhalation anesthesia, which has been previously demonstrated to impair long-term emotional memory consolidation and induce learning dysfunction through inducing hippocampal dysfunction. However, the underlying molecular mechanisms remain largely unknown. MicroRNAs (miRNAs) play critical roles in multiple cells apoptosis, including hippocampal neural. The present study, therefore, was aimed to investigate the miR-145 function on the hippocampal neural apoptosis induced by sevoflurane exposure. A hippocampal neural cell line HT22 was used, and treated with 4.1% sevoflurane. Cell viability and apoptosis were determined by MTT assay and flow cytometry, respectively. microRNA microarray was used to select differentially expression miRNAs in cells with sevoflurane exposure and controls. Results showed that sevoflurane could significantly induce the hippocampal neural cell apoptosis via mitochondria apoptotic pathway. Then, miR-145 was selected as a significantly down expression microRNA in sevoflurane treated HT22 cell lines, by microarray analysis and real-time PCR verification. Furthermore, we found that miR-145 overexpression could protect HT22 cells against apoptosis caused by sevoflurane. Bioinformatics analysis and dual-luciferase reporter assays indicated that Bnip3, which has a key role in the mitochondrial dysfunction, is a novel target of miR-145. Finally, we found that over expression of Bnip3 by pcDNA-Bnip3 transfection significantly induced apoptosis in HT22 cells, which was inhibited by miR-145 mimic. Therefore, it concluded that miR-145 could protect against sevoflurane-induced hippocampal apoptosis through the mitochondrial pathway at least by directly inhibiting its target gene-Bnip3 expression in hippocampal neural cell lines.