State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, P. R. China.
Department of Orthopedics, Renmin Hospital of Wuhan University, 9 Zhangzhidong Street, Wuhan, 430060, P. R. China.
Sci Rep. 2018 Apr 4;8(1):5624. doi: 10.1038/s41598-018-24050-6.
We developed a novel technique of bi-enzyme single-step hydrolysis, using recombinant chitosanase (McChoA) and exo-β-D-glucosaminidase (AorCsxA) constructed previously in our lab, to degrade chitosan. The hydrolysis product was shown by HPLC, FTIR, and chemical analyses to be a mixture (termed "GC") composed primarily of glucosamine (80.00%) and chitooligosaccharides (9.80%). We performed experiments with a mouse osteoarthritis (OA) model to evaluate the anti-inflammatory effects of GC against OA. The three "GC groups" (which underwent knee joint damage followed by oral administration of GC at concentrations 40, 80, and 160 mg/kg·bw·d for 15 days) showed significantly downregulated serum expression of pre-inflammatory cytokines (IL-1β, IL-6, TNF-α), and significant, dose-dependent enhancement of anti-inflammatory cytokine IL-2, in comparison with Model group. Levels of C-reactive protein, which typically rise in response to inflammatory processes, were significantly lower in the GC groups than in Model group. Thymus index and levels of immunoglobulins (IgG, IgA, IgM) were higher in the GC groups. Knee joint swelling was relieved and typical OA symptoms were partially ameliorated in the GC-treated groups. Our findings indicate that GC has strong anti-inflammatory effects and potential as a therapeutic agent against OA and other inflammatory diseases.
我们开发了一种新的双酶一步水解技术，使用先前在我们实验室构建的重组壳聚糖酶（McChoA）和外切-β-D-葡糖胺酶（AorCsxA）来降解壳聚糖。HPLC、FTIR 和化学分析表明，水解产物是一种主要由葡萄糖胺（80.00%）和壳寡糖（9.80%）组成的混合物（称为“GC”）。我们使用小鼠骨关节炎（OA）模型进行实验，以评估 GC 对 OA 的抗炎作用。三个“GC 组”（膝关节损伤后，分别以 40、80 和 160mg/kg·bw·d 的浓度口服 GC 治疗 15 天）与模型组相比，血清中促炎细胞因子（IL-1β、IL-6、TNF-α）的表达显著下调，抗炎细胞因子 IL-2 的表达显著上调，呈剂量依赖性。通常在炎症过程中升高的 C 反应蛋白水平在 GC 组中明显低于模型组。GC 组的胸腺指数和免疫球蛋白（IgG、IgA、IgM）水平更高。GC 治疗组缓解了膝关节肿胀，部分改善了典型的 OA 症状。我们的研究结果表明，GC 具有很强的抗炎作用，有望成为治疗 OA 和其他炎症性疾病的药物。
