ATRA Improves Nerve Function After SAH by Promoting Microglia M2 Transformation

CHEN Bo; CHEN Hao; SUN Luyuan; LI Linhe; LIN Shan; ZHOU Jingyi; GUAN Ning

doi:10.3969/j.issn.2096-305X.2025.02.003

Abstract：Objective To clarify the effects of all-trans retinoic acid(ATRA)on neurological damage and microglial polarization after subarachnoid hemorrhage(SAH).Methods Eighteen male Kunming mice were randomly divided into three groups:Sham group,SAH group,and SAH+ATRA group,with 6 mice in each group.The SAH model was created by injecting blood into the occipital cistern.The experimental animals in each group were randomly divided into two groups,A and B,and the neurological function score of the mice in each group was performed 24 hours after surgery.After the evaluation,the brain tissue was kept on the ice,paraffin sections of group A were made for HE staining and immunohistochemistry,and group B was used for brain edema determination and ELISA.Results Compared with the Sham group,the SAH group showed a significant decrease in neurological function scores(P＜0.05),while the SAH+ATRA group showed a significant increase compared to the SAH group(P＜0.05);according to the comparison of brain water content measurements,the brain water content of SAH group mice was markedly increased compared to the Sham group(P＜0.05),while the brain water content of SAH+ATRA group mice lessened compared to the experimental results of SAH group mice(P＜0.05);the immunohistochemical staining results showed that the expression levels of small glial cell specific markers CD206 and CD163 in the brain tissue of the SAH group were relatively higher than those of the Sham group(P＜0.05),while the expression levels of small glial cell specific markers CD206 and CD163 in the SAH+ATRA group were significantly increased(P＜0.05);the ELISA results showed that compared with the Sham group,the SAH group had anti-inflammatory mediators IL-10 and TGF in brain tissue-β The expression level increased(P＜0.05),while the SAH+ATRA group had IL-10 and TGF levels-β The expression level significantly increased(P＜0.05).Conclusion ATRA treatment for subarachnoid hemorrhage can effectively improve neurological function,which is likely achieved by promoting the transformation of microglia into M2 type.