A polysaccharide from Periplaneta americana promotes macrophage M2 polarization, exhibiting anti-inflammatory and wound-healing activities.

A miscellaneous polysaccharide, PAP55-3-1, with a molecular weight of 23.03 kDa, was isolated from Periplaneta americana through extraction with dilute alkali solution, ethanol precipitation, and column chromatography purification. Structural analysis shows that PAP55-3-1 is mainly composed of five monosaccharides: galactosamine hydrochloride, glucosamine hydrochloride, galactose, glucose and mannose. Its main glycosidic bonds are: Manp-(1→, Galp-(1→, →3)-Galp-(1→, →3,6)-Manp-(1→, →2,6)-Manp-(1→, →6)-Manp-(1→, →4)-Galp-(1→, →6-Glcp-(1→, →6)-Galp-(1→, →2)-Manp-(1 →, →3,4)-Glcp-(1→, →3,6)-Galp-(1→. In vitro experiments demonstrated that PAP55-3-1 can effectively inhibit reactive oxygen species (ROS) and O production following HOinduction. After HOinduction, HIF-1α (hypoxia-inducible factor) was translocated in mitochondria PAP55-3-1 increased localization of HIF-1α was located on mitochondria to maintain the stability of mitochondrial function stability, thereby effectively inhibiting HO-induced mitochondrial oxidative damage. Additionally, PAP55-3-1 inhibited the M1 polarization of macrophages stimulated by HO and promoted the phenotype polarization of macrophages from M1 to M2, displaying anti-inflammatory and pro-repair properties. In vivo experimental results indicated that PAP55-3-1 promoted wound healing in mice. Immunohistochemical experiments revealed a reduction in CD68 expression and increase in CD206 expression in both positive and the high-dose polysaccharide group control group. This further demonstrated that PAP55-3-1 promotes the phenotype polarization of macrophages from M1 to M2, exerting anti-inflammatory and wound-healing activities.