Changes in Matrix Gene and Protein Expressions After Single or Repeated Exposure to One Minimal Erythemal Dose of Solar-simulated Radiation in Human Skin In Vivo

Abstract

Damage to the skin extracellular matrix (ECM) is the hallmark of long-term exposure to solar UV radiation. The aim of our study was to investigate the changes induced in unexposed human skin in vivo after single or repeated (five times a week for 6 weeks) exposure to 1 minimal erythemal dose (MED) of UV solar-simulated radiation. Morphological and biochemical analyses were used to evaluate the structural ECM components and the balance between the degrading enzymes and their physiologic inhibitors. A three-fold increase in matrix metalloproteina.se 2 messenger RNA (mRNA) (P < 0.02, unexposed versus exposed) was observed after both single and repeated exposures. Fibrillin 1 mRNA level was increased by chronic exposure (P < 0.02) and unaltered by a single MED. On the contrary, a single MED significantly enhanced mRNA levels of interleukin-1α (IL-1α), IL-1β (P < 0.02) and plasminogen activator inhibitor-1 (P < 0.05). Immunohisto-chemistry demonstrated a significant decrease in Type-I procollagen localized just below the dermal-epidermal junction in both types of exposed sites. At the same location, the immunodetected tenascin was significantly enhanced, whereas a slight increase in Type-IΠ procollagen deposits was also observed in chronically exposed areas. Although we were unable to observe any change in elastic fibers in chronically exposed buttock skin, a significant increase in lysozyme and alpha-1 antitrypsin deposits on these fibers was observed. These results demonstrate the existence of a differential regulation, after chronic exposure compared with an acute one, of some ECM components and inflammatory mediators.

The benefit of daily photoprotection

“…Types I and III procollagens were predominantly located in the extracellular papillary dermis. 2 In 1SSR biopsy specimens, type I procollagen decreased significantly whereas type III was unaltered. Pretreatment with the photoprotecting DC (1SSR/1DC) prevented type I procollagen decrease.…”

“…Using a double staining procedure, we looked simultaneously at the elastin component of elastic fibers and lysozyme or alpha-1 antitrypsin, which have been described to be associated with damaged elastic fibers. 2,16,17 Sixweek SSR exposure (1SSR) did not induce any significant change in the elastin network. However, lysozyme and alpha-1 antitrypsin deposits on elastin fibers were significantly increased in 1SSR skin biopsy specimens.…”

“…[1][2][3] In body sites regularly exposed to sun, skin damage caused by photoaging is superimposed on tissue degeneration resulting from chronologic aging. Chronologic aging alone, as seen in sunprotected sites, leads to remarkably few clinically apparent changes.…”

Expression of Cathepsins in Human Skin Photoaging

“…Five areas received no exposure (recorded as control). The other 5 areas were exposed to 1 MED of SSR/day for 5 days/ week for a total of 6 weeks, as previously reported [25] . At intervals of 48 h, 72 h, 7, 14, 21, 28, 35 and 42 days, skin moisture and melanin were analyzed using the bioengineering devices (Corneometer CM 825 and Mexameter MX 18; CK, Germany).…”

Moisture absorption and retention properties, and activity in alleviating skin photodamage of collagen polypeptide from marine fish skin

“…The indirect damage induced by UV irradiation is suggested to be initiated by ROS, such as superoxide anion radical (O 2 ÀÅ ), perhydroxy radical (HOO Å ), hydrogen peroxide (H 2 O 2 ), hydroxyl radical (OH ÀÅ ), and singlet oxygen ( 1 O 2 ). Substantial evidence indicates that ROS are involved in connective tissue alterations, for example, levels of type I and III collagen precursors, the number of cross-links, the ratio of type III/I collagen, water content, total lipids level, glycosaminoglycan content, and elastin levels (Seite et al, 2004).…”