Tong Bei, Yu Juntao, Wang Ting, Dou Yannong, Wu Xin, Kong Lingyi, Dai Yue, Xia Yufeng
Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing 210009, China.
State Key Laboratory of Natural Medicines, Department of Natural Medicinal Chemistry, China Pharmaceutical University, Nanjing 210009, China.
Mol Immunol. 2015 May;65(1):94-103. doi: 10.1016/j.molimm.2015.01.014. Epub 2015 Feb 2.
Sinomenine (SIN) has long been used as a therapeutic agent of rheumatoid arthritis (RA) in China. However, the discrepancy between low oral bioavailability and higher minimal effective concentration made its action mode mysterious. The present study aimed to gain insight into the mechanisms by which SIN suppressed collagen-induced arthritis (CIA) in rats in view of Th17 and regulatory T (Treg) cell balance. SIN was orally administered, and the clinical symptoms of CIA rats were monitored; inflammatory cytokines levels in serum were measured by ELISA; pharmacokinetic studies were performed in normal and CIA rats; Th17 and Treg cell frequencies were analyzed by flow cytometry. The data showed that SIN treatment resulted in a dramatic decrease of arthritis scores and paw volume of CIA rats, which was accompanied by down-regulation of IL-17A and up-regulation of IL-10 in rat serum. The frequency of Treg cells was increased and the frequency of Th17 cells was decreased in the gut lymphoid tissues of SIN-treated rats. Immunohistochemistry assay demonstrated that more α4β7-positive cells were detained in joint tissues after SIN treatment. Moreover, the anti-arthritis efficacy of SIN disappeared when it was given by intraperitoneal injection, further confirming the action of SIN was gut-dependent. In conclusion, SIN exerts anti-RA action probably through modulating the frequencies of Treg cells and Th17 cells in intestinal lymph nodes and yielding a trafficking of lymphocytes (especially Treg cells) from gut to joint.
青藤碱（SIN）在中国长期以来一直被用作类风湿性关节炎（RA）的治疗药物。然而，口服生物利用度低与较高的最小有效浓度之间的差异使得其作用方式成谜。本研究旨在从Th17细胞和调节性T（Treg）细胞平衡的角度深入了解SIN抑制大鼠胶原诱导性关节炎（CIA）的机制。口服给予SIN，并监测CIA大鼠的临床症状；通过酶联免疫吸附测定法（ELISA）检测血清中的炎性细胞因子水平；在正常大鼠和CIA大鼠中进行药代动力学研究；通过流式细胞术分析Th17细胞和Treg细胞的频率。数据显示，SIN治疗导致CIA大鼠的关节炎评分和爪体积显著降低，同时大鼠血清中白细胞介素-17A（IL-17A）下调，白细胞介素-10（IL-10）上调。在接受SIN治疗的大鼠肠道淋巴组织中，Treg细胞频率增加，Th17细胞频率降低。免疫组织化学分析表明，SIN治疗后关节组织中滞留了更多α4β7阳性细胞。此外，当通过腹腔注射给予SIN时，其抗关节炎功效消失，进一步证实SIN的作用依赖于肠道。总之，SIN可能通过调节肠道淋巴结中Treg细胞和Th17细胞的频率，并使淋巴细胞（尤其是Treg细胞）从肠道向关节迁移来发挥抗类风湿性关节炎作用。
