DISACCHARIDE ANALYSIS OF HUMAN SKIN GLYCOSAMINOGLYCANS IN SUN-EXPOSEDAND SUN-PROTECTED SKIN OF AGED PEOPLE

The total amount of main disaccharide units of skin glycosaminoglycans was compared between sun-exposed (n = 12) and sun-protected skin (n = 14) of aged people using high performance liquid chromatography after labeling with 1-phenyl-3-methyl-5-pyrazolone. The total amount of mai n disaccharide units in sun-exposed skin was comparable to sun-protect ed skin presumably due to the diversity of individuals. Consequently, we compared sun-exposed skin with sun-protected skin in identical indi viduals (n = 6). The total amount of main disaccharide units in sun-ex posed skin was significantly greater than that in sun-protected skin ( P < 0.05). In addition, the ratio of Delta Di-HA (hyaluronic acid, HA) /Delta Di-4S (dermatan sulfate, DS) in sun-exposed skin showed a decre asing trend as compared with sun-protected skin in four of six individ uals. These results are in agreement with our previous results obtaine d in animal experiments of photoaging, i.e., hairless mouse skin expos ed to repeated UV irradiation showed an increase in total amount of ma in disaccharide units and a decrease in the ratio of Delta Di-HA(HA)/D elta Di-4S(DS). We could confirm similar changes in skin glycosaminogl ycans both in human and murine photoaging supporting the appropriate r ationale for using the hairless mouse as an animal model for photoagin g. Again, disaccharide analysis should provide a useful method to exam ine the biochemical changes of skin glycosaminoglycans in human photoa ging.