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-*, -*6Glcp-(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 O2_ production following H2O2_induction. After H2O2_induction, HIF-1 alpha (hypoxia-inducible factor) was translocated in mitochondria PAP55-3-1 increased localization of HIF-1 alpha was located on mitochondria to maintain the stability of mitochondrial function stability, thereby effectively inhibiting H2O2-induced mitochondrial oxidative damage. Additionally, PAP55-3-1 inhibited the M1 polarization of macrophages stimulated by H2O2 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.