芍药甘草汤调控血浆外泌体miR-216a-5p干预脊髓损伤后肌痉挛的研究OA

Objective To investigate the mechanism by which Shaoyao Gancao Decoction(SGD)intervenes spasm in spinal-cord-injured(SCI)rats.Methods ① Forty male SD rats were randomly assigned to four groups(n=10 each):Normal,Model,SGD and Positive.Except for the Normal group,rats in other groups received spinal cord hemisection at T9-10 to establish the SCI model.The third day after surgery,rats in Normal and Model groups were gavaged with de-ionized water;Rats in SGD group were gavaged with SGD(at the dose of 3.3 g/kg),and rats in the Positive group were gavaged with baclofen(at the dose of 1.35 mg/kg).The treatment lasted for 2 weeks.Drug efficacy was evaluated with the Basso-Beattie-Bresnahan(BBB)locomotor score.HMGB1 protein in spinal cord homogenates and expression of miR-216a-5p levels were quantified.The regulatory relationship between miR-216a-5p and HMGB1 was further validated by a dual-luciferase reporter gene assay.②Spinal-cord neurons were cultured in vitro,the effect of HMGB1 expression by SGD and miR-216a-5p mimic/inhibitor were assessed.③ Fifty additional SD rats were divided into Model,SGD,miR-216a-5p mimics,miR-216a-5p inhibitor,and exosome groups(n=10 each)to observe HMGB1 expression after the respective interventions.Results ① After 1 and 2 weeks of treatment,BBB scores in the SGD group were markedly higher than in the Model group(P<0.01),exhibited comparable efficacy to the Positive group.The level of HMGB1 increased after the SCI.After the treatment,the HMGB1 decreased in spinal cord tissue,meanwhile the miR-216a-5p expression in the plasma exosome increased.Dual-luciferase reporter gene assay confirmed that the HMGB1 was the target gene of miR-216a-5p.② In cultured neurons in vitro,HMGB1 was up-regulated in the Model group;HMGB1 down-regulated after the SGD and miR-216a-5p mimic transfection,while the miR-216a-5p inhibitor played a promotion role in the expression of HMGB1.③Further animal experiments confirmed that miR-216a-5p from plasma exosomes in the SGD group inhibited the expression of HMGB1 in spinal cord tissue.Conclusion SGD exerts a positive effect on neural repair in SCI rats by downregulating miR-216a-5p in plasma-derived exosomes,which consequently suppresses the expression of HMGB1 in spinal cord tissue.