The Effects of PUVA on the Morphologic Changes , Proliferation of Cultured Human Keratinocytes , and on the Proliferation , Melanization and Dendricity of Cultured Human Melanocytes / 대한피부과학회지

BACKGROUND: The combination of psoralen and UVA (PUVA) as a model of photochemotherap, has been used in a wicle variety of cutaneous disorders such as psoriasis, vitiligo, mycosis fungoides and atopic dermatitis. The mechanism of PUVA of psoriasis is based on the fact. that PUVA causes photoconjugation of psoralens to DNA and a subsequent suppression of mitosis, DNA synthesis, and keratinocyte proliferation. Although PUVA apparently inhibits keratinocytie proliferation and is effective therefore in the treatment of psoriasis, PUVA increases pigmentations by stimulating melanocyte proliferation and melanin synthesis in vivo. OBJECTIVE: We tried to investigate the PUVA effects on the proliferation and different,iation in cultured human keratinoc tes and melanocytes. METHODS: We examined morphologic changes, and the number of the cultured human keratinocytes and melanoiytes and melanin contents in a control group and experimental group. (UVA group, 8-MOP group and PUVA group). i.e., UVA group was exposed to UVA at 60mJ, of. 8-MOP group was acJded at dose of 2 x 10 M to medium for 30 minutes. PUVA group was exposed to UVA at 60mJ, of after adding in 8 MOP at Zx 10 M for 30 minutes. RESULTS: 1. Morphologic changes of cultured human keratinocytes and melanocytes. There were no significent changes between the control group and the experimental groups in keratinocytes and melanocytes after 24, 48 and 72 hours culture. The number and length of meianocyte dendrites showecl no significant differences between the groups after 24, 48 and 72 hours culture(p>0.05). 2. Proliferation of cultured human keratinocytes and melanocytes 1) The number of keratinocytes in 8-MOP and PUVA groups decreased significantly more than in the control and LVA groups at 72nd hour after culture (p0.05). 3. Melanin contents in iultured human melanocytes The melanin contents increased significantly in the PUVA groups compared to that in the other groups at 72nd hour after culture (p<0.01). CONCLUSION: In culturel human keratinocytes, PUVA has no effect on the morphology and differentiation, hut inhibit proliferation. In cultured human melanocytes, PUVA has no effect on morphology and proliferation, but it increases the melanin contents.

The effects of a single exposure of UVB on morphologic changes and proliforation in cultured normal melanocytes / 대한피부과학회지

In humans, the major stimulus for cutaneous pigmentation is ultraviolet radiation. Little is known about the mechanism underlying this response, in part, because of the complexity of the interactions involving the whole epidermis. The present stucy was undertake to evaluate the effects of a single exposure of UVB on cultured normal melanocytes. Melanocytes were exposed to UVB from 5.1 mJ/cm to 203 mJ/cm. The results were as follows : 1. The main morphologic changes in UVB-exposed groups w re larger sized cells, more blunted dendrites, and shorter dendrites than in the control group. These cells increased sized according to the increased doses of VVB, but above 101.5 mJ/cm, the melanocytes shrunk and were destroyed. 2. From 20.3 mJ/cm of UVB, the proliferation of melanocyte was decreased, Especially, there was statistical!y significant difference above 50.8 mJ/cm (p<0.05, p<0.01). 3. The antiproliferativo effect increased with the passage of tirie after UVB exposure. So, cell count could not be done in 101.5 mJ/cm and 203 mJ/cm on the third day, and in 50.8 mJ/cm, 101.5 m J/cm and 203 mJ/cm on the seventh day. 4. Statistically the melanin content per well was significantl dicreased to 11-28% of each control group with dose above 50.8 mJ/cm (p<0.05, p<0.01). The melanin content per cell was increased to 107-128% of each control group when doses were below 20.3 mJ/cm and decreased to 49-79% of each control group when above 0.8 mJ/cm on the third day, but there was no statistically significant difference. In summary, when melarocytes were exposed to UVB, morphclogic changes progressed to cell differentiation. The results also suggested that a low or dose of UVB has an antiproliferative arid mild melanogenic effect, and a higher dose of UVB has a direct cytotoxic effect.