Protective effect of Inonotus obliquus polysaccharide on MGO-induced nonenzymatic glycation fibroblasts

Background

The nonenzymatic glycation of fibroblasts causes functional downregulation and behavioral disorders in the skin.

Methods

To investigate the effect of Inonotus obliquus on the nonenzymatic glycation of skin, we examined the inhibition of advanced glycation end products (AGEs) using four extraction methods: n-butanol, ethyl acetate, n-hexane and aqueous alcohol precipitation. The physical properties and chemical structure of the most effective, purified, crude I. obliquus polysaccharide (IOP) were examined. The effects of IOP on carboxymethyl lysine (CML) accumulation, inflammatory factor release, reactive oxygen species (ROS) production, key extracellular matrix (ECM) protein (MMP 1, 2 and 9; FN-1, LM-5 and COL-1) mRNA expression, and cell survival, migration and adhesion were also examined via cellular assays.

Results

IOP is a polysaccharide with a molecular weight (Mw) of 2.396 × 104 (±6.626%) that is composed mainly of glucose, galactose, xylose, mannose and arabinose (29.094:21.705:14.857:9.375:7.709). In addition, a cellular antiglycation assay showed that IOP, which can promote ECM formation by inhibiting the accumulation of CML, inhibiting the release of inflammatory factors (IL-1β, IL-6, and TNF-α), inhibiting the production of reactive oxygen species (ROS), inhibiting the expression of matrix metalloproteinases (MMP-1\-2\-9), promoting the synthesis of ECMs (COL1, FN1, and LM5), and improving cellular dysfunction, had strong antiglycation activity at concentrations in the range of 6-24 μg/mL.

Conclusion

IOP effectively reduced the levels of inflammatory factors and reactive oxygen species produced by AGEs, further preventing the impairment of cell behavior (decreased migration and reduced cell adhesion) and preventing the downregulation of the expression of key extracellular matrix proteins induced by AGEs. The results indicate the potential application of IOP as an AGE inhibitor in skin care.