Effects of Polysaccharides from Urtica macrorrhiza Hand.-Mazz. on Phagocytic Function and Polarization of Macrophage

Objective: To investigate the effects of Urtica macrorrhiza Hand.-Mazz. rhamnnogalacturonans (UMRG), and Urtica macrorrhiza Hand.-Mazz. arabinogalactan (UMAG) on the immunological function by regulating phagocytic and polarization of macrophages. Methods: The effects of UMRG and UMAG on the viability of macrophage were studied by the cell counting kit-8 (CCK-8). The effects of UMRG and UMAG on the phagocytosis of macrophage were investigated by neutral red assay, flow cytometry and laser confocal microscopy. The effects of UMRG and UMAG on macrophage polarization were studied by flow cytometry. The effects of UMRG and UMAG on the secretion of nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) were detected by Griess assay and enzyme-linked immunosorbent assay (ELISA). Results: UMRG and UMAG exhibited no significant cytotoxicity to macrophages in the concentration range of 10~320 µg/mL. Both UMRG and UMAG significantly enhanced the macrophage phagocytosis of neutral red and model antigens (P<0.05) by macrophage, and the activity of UMRG was stronger than UMAG. Both UMRG and UMAG significantly up-regulated the expression of CD86 and CD206 molecules on macrophage (P<0.01), however, the up-regulation proportion of CD86 was significantly higher than that of CD206, and the activity of UMRG was stronger than UMAG. Both UMRG and UMAG stimulated the secretion of NO, TNF-α, and IL-6 by macrophage (P<0.01). Conclusion: UMRG and UMAG from Urtica macrorrhiza Hand.-Mazz. can activate macrophage, enhance its phagocytic function and predominantly promote its polarization towards M1 type, thus they may be natural imunopotentiators. The activity of UMRG is stronger than UMAG.