Alterations in Dermal Collagen in Ultraviolet Irradiated Hairless Mice

Pomegranate as a cosmeceutical source: Pomegranate fractions promote proliferation and procollagen synthesis and inhibit matrix metalloproteinase-1 production in human skin cells

“…Damage to the skin occurs as a consequence of the natural aging process and damage is exacerbated in chronically sunexposed skin (photoaging) (Smith et al, 1962;Lavker, 1979;Lovell et al, 1987;Kligman and Balin, 1989;Oikrinen and Kallioinen, 1989;Schwartz et al, 1989;Schwartz et al, 1993; Abbreviations: ANOVA, analysis of variance; DMEM-FBS, Dulbecco's modified minimal essential medium supplemented with 10% fetal bovine serum; EA, ethyl acetate; EDTA, ethylenediamine tetraacetic acid; ELISA, enzymelinked immunosorbant assay; KBM, keratinocyte basal medium; KGM, keratinocyte growth medium; MMP-1, matrix metalloproteinase-1; RA, retinoic acid; SDS-PAGE, sodium dodecyl sulfate polyacrylamide gel electrophoresis; TDS, total dissolved solids Lavker, 1995). Skin damage is also seen as a consequence of diabetes (Prakash et al, 1974;Klenerman et al, 1996;Laing, 1998;Reiber, 1998), in other diseases that compromise the vasculature of the skin (Strigini and Ryan, 1996;Mendez et al, 1998;Stadelmann et al, 1998) and following long-term corticosteroid use (McMichael et al, 1996).…”

THE HAIRLESS MOUSE and PHOTOAGING

“…In contrast, Schwartz et al (1989), using antibodies directed against the helical domain of type I collagen, found no change after 10 weeks of UV-B irradiation. With purified specific rabbit antibodies directed against the aminopropeptide (pN al) of types I and 111 calf skin procollagens, these workers found the pN al of type I procollagen located at the dermal-epidermal junction of both UV-B irradiated and control skins.…”

“…The amount of type 111 collagen was expressed as a percentage of total collagen, followed by a determination of the ratio of type I11 in the irradiated skin over that in the ventral skin. Using a different technique of collagen extraction (pepsin digestion) Schwartz et al (1989) were unable to confirm changes in the ratio of types 1Wtotal collagen after 10 weeks despite higher doses of UV-B. undertook to correlate histochemical collagen damage with biochemical changes by sampling the skin at 4 week intervals for up to 24 weeks of UV-B irradiation (-4 MED/exposure).…”

Peeling agents and irritants, unlike tretinoin, do not stimulate collagen synthesis in the photoaged hairless mouse

“…The immunofluorescence methodology was as previously described [22]. Briefly, sections were cut on a cryostat (6 µm), placed in cold acetone for 5 min, rinsed with phosphate-buffered saline (PBS) and incubated with affinity-purified rabbit antibovine antibodies [22] directed against the aminopropeptide (pN type III) of type III procollagen for 30 min at 37°C.…”

“…Briefly, sections were cut on a cryostat (6 µm), placed in cold acetone for 5 min, rinsed with phosphate-buffered saline (PBS) and incubated with affinity-purified rabbit antibovine antibodies [22] directed against the aminopropeptide (pN type III) of type III procollagen for 30 min at 37°C. The sections were then rinsed with PBS and incubated for 30 min at 37°C with goat antirabbit IgG conjugated with fluorescein isothiocyanate (Organon Teknika; Cappel, West Chester, Pa.) After rinsing with PBS, the sections were mounted in PBS-glycerol (1 : 9, v/v) and examined with a Nikon 18 microscope.…”