Leite Paulo Emílio Correa, Gandía Luís, de Pascual Ricardo, Nanclares Carmen, Colmena Inés, Santos Wilson C, Lagrota-Candido Jussara, Quirico-Santos Thereza
Department of Cellular and Molecular Biology, Fluminense Federal University, Rio de Janeiro, Brazil.
Instituto Teófilo Hernando, Department of Pharmacology and Therapeutics, Autonomous University of Madrid, Madrid, Spain.
Brain Res. 2014 Jul 21;1573:27-36. doi: 10.1016/j.brainres.2014.05.004. Epub 2014 May 14.
Amount evidence indicates that α7 nicotinic acetylcholine receptor (nAChRα7) activation reduces production of inflammatory mediators. This work aimed to verify the influence of endogenous nAChRα7 activation on the regulation of full-blown muscular inflammation in mdx mouse with Duchenne muscular dystrophy. We used mdx mice with 3 weeks-old at the height myonecrosis, and C57 nAChRα7(+/+) wild-type and nAChRα7(-/-) knockout mice with muscular injury induced with 60µL 0.5% bupivacaine (bp) in the gastrocnemius muscle. Pharmacological treatment included selective nAChRα7 agonist PNU282987 (0.3mg/kg and 1.0mg/kg) and the antagonist methyllycaconitine (MLA at 1.0mg/kg) injected intraperitoneally for 7 days. Selective nAChRα7 activation of mdx mice with PNU282987 reduced circulating levels of lactate dehydrogenase (LDH, a marker of cell death by necrosis) and the area of perivascular inflammatory infiltrate, and production of inflammatory mediators TNFα and metalloprotease MMP-9 activity. Conversely, PNU282987 treatment increased MMP-2 activity, an indication of muscular tissue remodeling associated with regeneration, in both mdx mice and WTα7 mice with bp-induced muscular lesion. Treatment with PNU282987 had no effect on α7KO, and MLA abolished the nAChRα7 agonist-induced anti-inflammatory effect in both mdx and WT. In conclusion, nAChRα7 activation inhibits muscular inflammation and activates tissue remodeling by increasing muscular regeneration. These effects were not accompanied with fibrosis and/or deposition of non-functional collagen. The nAChRα7 activation may be considered as a potential target for pharmacological strategies to reduce inflammation and activate mechanisms of muscular regeneration.
大量证据表明，α7烟碱型乙酰胆碱受体（nAChRα7）的激活可减少炎症介质的产生。这项研究旨在验证内源性nAChRα7激活对杜氏肌营养不良症mdx小鼠严重肌肉炎症调节的影响。我们使用了3周龄处于严重肌坏死阶段的mdx小鼠，以及C57 nAChRα7(+/+)野生型和nAChRα7(-/-)基因敲除小鼠，通过在腓肠肌注射60µL 0.5%布比卡因（bp）诱导肌肉损伤。药物治疗包括腹腔注射选择性nAChRα7激动剂PNU282987（0.3mg/kg和1.0mg/kg）和拮抗剂甲基lycaconitine（MLA，1.0mg/kg），持续7天。用PNU282987选择性激活mdx小鼠的nAChRα7可降低循环中的乳酸脱氢酶（LDH，坏死导致细胞死亡的标志物）水平、血管周围炎性浸润面积以及炎症介质TNFα的产生和金属蛋白酶MMP-9活性。相反，在bp诱导的肌肉损伤的mdx小鼠和WTα7小鼠中，PNU282987治疗均增加了MMP-2活性，这表明与再生相关的肌肉组织重塑。PNU282987治疗对α7KO小鼠无影响，且MLA消除了mdx和WT小鼠中nAChRα7激动剂诱导的抗炎作用。总之，nAChRα7激活通过增加肌肉再生来抑制肌肉炎症并激活组织重塑。这些作用并未伴随纤维化和/或无功能胶原蛋白的沉积。nAChRα7激活可被视为减少炎症和激活肌肉再生机制的药理学策略的潜在靶点。
