为了探究铁皮石斛多糖（Dendrobium officinale Polysaccharide, DOP）硒化修饰工艺及铁皮石斛硒多糖（Selenated Dendrobium officinale Polysaccharide, SeDOP）免疫调节活性，采用单因素结合响应面法优化SeDOP制备工艺；建立RAW 264.7细胞增殖模型及环磷酰胺所致的免疫力低下动物模型，考察SeDOP免疫调节活性。结果表明，SeDOP的最佳制备工艺条件为：反应温度72 ℃，mNa2SeO3:mDOP=1.1，硝酸体积分数为0.6%，反应时间7.2 h，在此工艺条件下，SeDOP中硒含量为1.55 mg/g。细胞增殖试验显示，DOP与SeDOP可剂量依赖促进RAW 264.7细胞增殖，质量浓度为200 μg/mL时，DOP与SeDOP促进细胞增殖率分别为132.93%和175.44%。动物试验评价表明，与模型组相比，DOP及SeDOP组均能增大实验小鼠的免疫脏器指数，显著提高小鼠血清中IL-2、TNF-α和IFN-γ水平，DOP组IL-2、TNF-α和IFN-γ分别为155.31、184.26和152.91 pg/mL，SeDOP高剂量组分别为316.27、385.24和208.22 pg/mL。脾脏H&E染色结果显示，SeDOP中、高剂量组能明显改善环磷酰胺所致的脾脏受损。总体而言，SeDOP具有较好的免疫调节活性，且效果优于单纯的DOP，该研究可为DOP硒化修饰及补硒产品的开发应用奠定理论基础。

The modification of Dendrobium officinale polysaccharide (DOP) with selenium and the immune-regulating activity of selenated Dendrobium officinale polysaccharide (SeDOP) were investigated. The preparation of SeDOP was optimized using a combination of single-factor experiments and response surface methodology. The immunomodulatory activity of SeDOP was assessed using RAW 264.7 cell proliferation models and immunosuppressed animal models induced by cyclophosphamide. The results indicated that the optimal preparation conditions for SeDOP were as follows: reaction temperature of 72 ℃, mNa2SeO3: mDOP=1.1, the nitric acid volume fraction of 0.6%, and reaction time of 7.2 h, resulting in a selenium content in SeDOP of 1.55 mg/g. Cell proliferation assays demonstrated a dose-dependent enhancement of RAW 264.7 cell proliferation by both DOP and SeDOP at a concentration of 200 μg/mL; DOP and SeDOP increased cell proliferation rates by 132.9% and 175.4%, respectively. Animal experiments demonstrated that DOP and SeDOP increased the immune organ index in experimental mice compared to the model group. Serum levels of IL-2, TNF-α, and IFN-γ were significantly elevated in the DOP group, reaching 155.3, 184.2, and 152.9 pg/mL, respectively. In the SeDOP group, the values were 316.2, 385.2, and 208.2 pg/mL. H&E staining of the spleen indicated that SeDOP at medium and high doses significantly alleviated spleen damage induced by cyclophosphamide. Overall, SeDOP exhibited notable immunomodulatory activity, surpassing the effects of pure DOP. This study provides a theoretical foundation for developing and applying selenium-modified DOP and selenium supplements.

贵州省科技支撑计划项目（黔科合支撑[2020]4Y068）