Cosmeceutical effect on skin surface profiles and epidermis in UV-B-irradiated mice

IMPORTANCE These data may be useful for developing guidelines for clinicians and the general population related to the reversal of photoaging effects on the aging face damaged by solar radiation. OBJECTIVE To investigate antiaging effects of 4 commercially available topical agents on the dorsal skin in photoaged hairless mice. DESIGN AND SETTING Animal study at an academic medical center. Animals comprised 56 female Skh-1 hairless mice (6-8 weeks old). Skin samples were collected from nonirradiated intact mice (control), mice irradiated with UV-B for 8 weeks, mice irradiated with UV-B and then exposed to a topical cosmeceutical applied for 5 weeks, and UV-B-irradiated mice not exposed to cosmeceuticals and retained for 5 weeks until the end of the experiment. INTERVENTION The mice were exposed to UV-B light 3 times a week for 2 months, followed by topical application of a peptide, antioxidant, estrogen, and retinoic acid agent for 5 weeks. MAIN OUTCOMES AND MEASURES Surface features such as wrinklingwere analyzed from replicas along with histomorphometric determination of epidermal thickness, sebocyte counts, and immunohistochemical study of proliferating cell nuclear antigen (PCNA). RESULTS Exposure to UV-B induced significant wrinkle formation after 13 weeks, which was attenuated with treatments with a peptide cream, antioxidant mixture, and estrogen cream (mean [SD] Rz values: control [C], 60.7 [19.0]; irradiated [RAD], 51.8 [15.9] [P < .001]; irradiated-long [RAD-long], 86.0 [28.3] [P = .01]; antioxidant [AO], 45.2 [13.2]; peptide, 63.4 [18.8], estrogen, 64.6 [21.2]; retinoic acid [RA], 73.9 [28.5]; RAD-long vs C [P = .01], vs RAD [P < .001], vs estrogen [P = .04], vs peptide [P = .02], vs AO [P<001], vs RA [P = .25]. There was a trend of reversal of irradiation-induced augmentation of epidermal thickness in animals treated with the peptide and AO (mean [SD] epidermal width: C, 21.0 [2.2] μm; RAD, 41.3 [7.0] μm [P < .001]; RAD-long, 39.1 [11.0] μm[P = .006]; AO, 37.3 [14] μm [P < .001]; peptide, 33.9[3.8] μm [P = .01]; estrogen, 59.2 [9.2] μm [P = .003]; RA, 52.4 [8.7] μm [P < .001]). Retinoic acid augmented epidermal width and sebocyte counts (mean [SD] sebocyte data [number per gland]: C, 9.4 [2.0]; RAD, 11.69 [1.5] [P < .001]; RAD-long, 6.5 [1.3] [P = .73]; peptide, 7.2 [1.7] [P = .03]; estrogen, 4.1 [0.9] [P < .001]; AO, 7.2 [1.7] [P = .06]; RA, 11.0 [1.4] [P = .01]). Estrogen cream was effective in restoring surface features but enhanced thickness of epidermis in irradiated specimens. All groups had a higher PCNA index score except for peptide treatment, which brought it down to the control level (mean [SD] PCNA index values: C, 17.3 [1.5]; RAD, 32.4 [6.8] [P < .001]; RAD-long, 34.0 [6.1] [P < .001]; AO, 62.1 [3.5] [P = .01]; peptide, 20.1 [6.3] [P < .001]; estrogen, 56.8 [10.0] [P < .001]; RA, 35.2 [10.2] [P < .001]). CONCLUSIONS AND RELEVANCE Of the 4 cosmeceuticals tested within this experimental period, peptide cream and antioxidant mixture were the most effective overall in reversing photoaging effects; retinoic acid was the least effective of these topical agents.