Alginate oligosaccharides promote wound healing and induce macrophage M2 polarisation by activating the PI3K/AKT1...

The objective of this study was to investigate the effects of alginate oligosaccharides on wound cell proliferation, migration, apoptosis, macrophage polarisation, and wound healing. The results of the Cell Counting Kit-8, Transwell method, and caspase-3 immunofluorescence showed that alginate oligosaccharides effectively promoted keratinocyte proliferation, migration, and reduced apoptosis by activating the PI3K/AKT1 signalling pathway. The polarisation of macrophages was detected using iNOS and Arg-1 immunofluorescence. Alginate oligosaccharides induced M2 polarisation. This was negated after using an AKT1 inhibitor. In vitro cell experiments showed that alginate oligosaccharides did not affect macrophage proliferation but showed a significant reduction in macrophage numbers in in vivo animal wound models, accompanied by a trend in M2 polarisation. Although AOs had no direct in vitro antibacterial effect, their in vivo application modulated the composition of wound microbiota, which may be related to AOs induced macrophage M2 polarization and the improvement of local inflammatory response. The combined effects of alginate oligosaccharides on keratinocytes and macrophages ultimately promoted wound healing and altered microbiota composition, thereby providing a new, potential treatment option for wound healing(Fig. 1).