The present study involves the structural characterization of an iota-carrageenan from Agardhiella ramosissima (IC-Ar) and its ability to suppress the inflammatory response in experimental arthritis. The IC-Ar was structurally characterized by Size Exclusion Chromatography (SEC) and Nuclear Magnetic Resonance (NMR) techniques. Experimentally, the mice were treated with IC-Ar (3, 10, or 30 mg/kg) e submitted to arthritis with zymosan and Complete Freund's Adjuvant (CFA). IC-Ar has a molecular mass of 730 KDa and contains 3,6 anhydro-α-d-galactose-2 sulfate (DA2S), β-d-galactose-4 sulfate (G4S) and glucose, structural characteristic typical of an iota carrageenan. IC-Ar treatment reduced zymosan-induced hypernociception, in a dose-dependent manner, accompanied by reduced edema, vascular permeability, and histopathological scores. Likewise, IC-Ar also significantly decreases MPO activity, leukocytes, neutrophils, IL-1β, and nitrite levels in the synovial fluid. Therapeutically, IC-Ar inhibited the hypernociception, edema, and arthritic index in both acute, sub-chronic, and chronic phases of CFA-induced arthritis. In summary, we demonstrated the protective efficacy of an iota-carrageenan extracted from A. ramosissima in arthritis models by negatively modulating the inflammatory response and by reducing polymorphonuclear cell migration, IL-1β, and nitrite levels, culminating in the inhibition of hypernociception and edema. Thus, IC-Ar could be a promising molecule to treat arthritis conditions.

本研究涉及来自Agardhiella ramosissima (IC-Ar) 的 iota-角叉菜胶 (IC-Ar) 的结构特征及其抑制实验性关节炎炎症反应的能力。通过尺寸排阻色谱 (SEC) 和核磁共振 (NMR) 技术对 IC-Ar 进行结构表征。实验上，用 IC-Ar（3、10 或 30 mg/kg）治疗小鼠，并用酵母聚糖和弗氏完全佐剂 (CFA) 治疗关节炎。IC-Ar 的分子量为 730 KDa，含有 3,6 脱水-α- d-半乳糖-2 硫酸盐 (DA2S)、β -d-半乳糖-4 硫酸盐 (G4S) 和葡萄糖，具有 iota 卡拉胶的典型结构特征。IC-Ar 治疗以剂量依赖性方式减少酵母聚糖诱导的过度伤害性，同时减少水肿、血管通透性和组织病理学评分。同样，IC-Ar 还显着降低滑液中的 MPO 活性、白细胞、中性粒细胞、IL-1β 和亚硝酸盐水平。在治疗上，IC-Ar 抑制 CFA 诱导的关节炎的急性期、亚慢性期和慢性期的痛觉过度、水肿和关节炎指数。总之，我们证明了从分枝A. ramosissima中提取的iota-角叉菜胶在关节炎模型中的保护功效，通过负向调节炎症反应并减少多形核细胞迁移、IL-1β和亚硝酸盐水平，最终抑制过度伤害感受和水肿。因此，IC-Ar 可能是治疗关节炎疾病的有前途的分子。