Guan Qing-Yun, Lin Ya-Ru, Li Ling-Yu, Tang Zhi-Mei, Zhao Xin-Huai, Shi Jia
Key Laboratory of Dairy Science, Ministry of Education, Northeast Agricultural University, Harbin 150030, China.
School of Biology and Food Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China.
Foods. 2021 Nov 12;10(11):2788. doi: 10.3390/foods10112788.
The immunomodulation of chemically selenylated polysaccharides has been attracting more attention recently, but the corresponding performance of the yam polysaccharides (YPS) with lower selenylation extent remains, thus far, unsolved. In this study, the YPS was selenylated with NaSeO under acidic conditions generated by HNO to reach two lower selenylation extents, yielding two selenylated YPSs, namely SeYPS-1 and SeYPS-2 with selenium contents of 715 and 1545 mg/kg, respectively. The results indicated that YPS, SeYPS-1, and SeYPS-2 all had in vitro immuno-modulation when using RAW 264.7 macrophages and murine splenocytes as cell models. In detail, the three polysaccharide samples at dose levels of 5-160 μg/mL showed insignificant cytotoxicity to the macrophages and splenocytes with cell exposure times of 12-24 h, because of the measured values of cell viability larger than 100%. However, NaSeO at dose levels of 1.3-3.25 μg/mL mostly caused obvious cytotoxic effects on the cells, resulting in reduced cell viability values or cell death, efficiently. The results demonstrated that, compared with YPS, both SeYPS-1 and SeYPS-2 at a lower dose level (5 μg/mL) were more active at promoting phagocytosis activity, increasing the CD4/CD8 ratio of the T-lymphocyte sub-population in the murine splenocyte, improving cytokine secretion, including interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α in the macrophages, or increasing interferon-γ secretion, but suppressing IL-4 production in the splenocytes. Consistently, SeYPS-2 has more potential than SeYPS-1 at exerting these assessed bioactivities in the cells. Thus, we conclude that a chemical modification of YPS using trace element Se at a lower selenylation extent could bring about higher immunomodulatory activity towards macrophages and splenocytes, while selenylation extent of YPS is a critical factor used to govern the assessed activity changes of YPS.
化学硒化多糖的免疫调节作用近来备受关注，但硒化程度较低的山药多糖（YPS）的相应性能至今仍未得到解决。在本研究中，YPS在由HNO产生的酸性条件下用NaSeO进行硒化，以达到两个较低的硒化程度，得到两种硒化YPS，即SeYPS - 1和SeYPS - 2，其硒含量分别为715和1545 mg/kg。结果表明，当使用RAW 264.7巨噬细胞和小鼠脾细胞作为细胞模型时，YPS、SeYPS - 1和SeYPS - 2均具有体外免疫调节作用。具体而言，在细胞暴露时间为12 - 24 h时，三种多糖样品在5 - 160 μg/mL的剂量水平下对巨噬细胞和脾细胞显示出不显著的细胞毒性，因为细胞活力的测量值大于100%。然而，1.3 - 3.25 μg/mL剂量水平的NaSeO大多对细胞产生明显的细胞毒性作用，有效地导致细胞活力值降低或细胞死亡。结果表明，与YPS相比，较低剂量水平（5 μg/mL）的SeYPS - 1和SeYPS - 2在促进吞噬活性、增加小鼠脾细胞中T淋巴细胞亚群的CD4/CD8比值、改善细胞因子分泌（包括巨噬细胞中的白细胞介素 - 6（IL - 6）、IL - 1β和肿瘤坏死因子 - α）、增加干扰素 - γ分泌，但抑制脾细胞中IL - 4产生方面更具活性。一致地，SeYPS - 2在发挥这些评估的细胞生物活性方面比SeYPS - 1更具潜力。因此，我们得出结论，在较低硒化程度下用微量元素Se对YPS进行化学修饰可以对巨噬细胞和脾细胞产生更高的免疫调节活性，而YPS的硒化程度是控制YPS评估活性变化的关键因素。
