Up-regulation of miR-106a targets LIMK1 and contributes to cognitive impairment induced by isoflurane anesthesia in mice

Background Postoperative cognitive dysfunction (POCD) had a great relationship with anesthesia during surgery, and miRNAs have been found involved in anesthesia-induced cognitive impairment. Objective To explore the role and potential mechanism of miR-106a in isoflurane anesthesia-induced cognitive impairment. Methods Adult male mice were treated with isoflurane anesthesia; Morris water maze tests and fear conditioning tests were performed; and expression levels of miR-106a and LIMK1 were determined by quantitative real-time PCR (qRT-PCR) and western blot. Dual luciferase reporter assay was used to determine the binding of miR-106a and 3'UTR of LIMK1. To verify the role of miR-106a, antagomir of miR-106a were intrahippocampally injected. Finally, expression of BCL2 apoptosis regulator (Bcl-2), LIM domain kinase 1 (LIMK1), BCL2-associated X, apoptosis regulator (Bax) and cleaved caspase3 was determined by western blot. Results In isoflurane anesthesia-treated group (IS), the percentage of target quadrant dwell time was significantly lower and the escape latency was significantly higher than in the control group (sham), and the freezing behavior of IS was significantly less in contextual fear conditioning tests. Expression levels of miR-106a were increased and those of LIMK1 were decreased in response to IS. Dual luciferase reporter assay showed that miR-106a could bind with the 3'UTR of LIMK1. Decreased expression levels of miR-106a improved the cognitive impairment of the mice treated with isoflurane. Intrahippocampally injected antagomir of miR-106a also increased LIMK1 and Bcl-2 levels, decreased the BAX and cleaved caspase3 expression levels in the mice treated with isoflurane. Conclusion Decrease of LIMK1 expression by miR-106a played an important role in isoflurane anesthesia-induced cognitive impairment.