miR-483-5p通过调控小胶质细胞M1/M2极化减轻心肺复苏后大鼠神经功能损伤OA

AIM:To elucidate the role and underlying molecular mechanism of microRNA-483-5p(miR-483-5p)in regulating microglial polarization and neurological outcomes following cardiopulmonary resuscitation(CPR).METHODS:In vivo,an asphyxia-induced cardiac arrest(CA)/CPR model was established in Wistar rats.Four weeks before CA/CPR induction,an empty adeno-associated virus serotype 9(AAV9)vector(AAV9-NC),an AAV9 vector ex-pressing a negative control sponge(AAV9-sponge-NC),an AAV9 vector expressing miR-483-5p(AAV9-miR-483-5p),and an AAV9 vector expressing a miR-483-5p sponge(AAV9-sponge-miR-483-5p)were stereotactically injected into the lateral ventricle.Sixty rats were randomly assigned to 6 groups:sham,CA/CPR,CA/CPR+AAV9-NC,CA/CPR+AAV9-sponge-NC,CA/CPR+AAV9-miR-483-5p,and CA/CPR+AAV9-sponge-miR-483-5p groups(n=10).Hippocampal histo-pathology was assessed using HE and Nissl staining.Neurological function was evaluated by neurological deficit score and Morris water maze test.Microglial activation was determined by immunofluorescence staining for ionized calcium-binding adapter molecule 1(Iba1)in the hippocampus.Protein expression levels of microglial polarization markers and inflamma-tory mediators were quantified by Western blot analysis.In vitro,an oxygen-glucose deprivation/reoxygenation(OGD/R)model was established in BV2 microglial cells.The cells were randomly divided into the following groups:NC,OGD/R,OGD/R+LV-NC,OGD/R+miR-483-5p mimic,and OGD/R+miR-483-5p inhibitor.The miR-483-5p expression was quan-tified using RT-qPCR.Western blot,immunofluorescence staining and flow cytometry were used to assess the protein ex-pression levels and positive rates of microglial polarization-related markers.RESULTS:Following CA/CPR,miR-483-5p expression was significantly down-regulated in the hippocampus,concomitant with enhanced microglial activation and a shift towards the pro-inflammatory(M1)phenotype,along with impaired neurological function.Overexpression of miR-483-5p markedly reduced hippocampal histopathological damage,improved neurological performance,and promoted mi-croglial polarization toward the anti-inflammatory M2 phenotype,thereby enhancing neurological outcomes.Consistently,in vitro experiments further demonstrated that OGD/R promoted M1 polarization of BV2 microglia and increased pro-inflam-matory cytokine expression.Overexpression of miR-483-5p facilitated M2 polarization,whereas its inhibition promoted M1 polarization and exacerbated inflammatory responses.CONCLUSION:miR-483-5p may attenuate post-resuscitation brain injury and improve neurological outcomes by regulating microglial polarization from the pro-inflammatory M1 pheno-type toward the anti-inflammatory M2 phenotype.