| Section 1 A preliminary study of broadband ultraviolet radiation and 17p-estradiol on non-classical Wnt pathways of human melanocytesObjective To study influence of ultraviolet radiation and 17β-estradiol on the proliferation, tyrosinase activity and melanin level of melanocyte, and the possible effects of ultraviolet radiation and 17β-estradiol on melanogenesis-related gene through the regulation of noncanonical Wnt pathway.Methods Primary melanocytes were isolated from skin of normal human in vitro. They were irradiated with different doses of ultraviolet radiation or cultured in medium containing different concentrations of 17β-estradiol. CCK8 assay was performed to evaluate the proliferation and activity of melanocytes; tyrosinase activity was evaluated with L-dopa staining assay; melanin level was detected by NaOH dissolution assay. Appropriate ultraviolet radiation dose and concentration of 17p-estradiol were selected to perform next stimulation tests. Real-time PCR was applied to detect mRNA expression of non-classical pathway after ultraviolet radiation or 17β-estradiol stimulation. Western blot was done to detect protein expression of non-classical pathway after ultraviolet radiation or 17β-estradiol stimulation. One-way ANOVA was used for statistical analysis of the differences between groups.Results Proliferation and activity of melanocytes were decreased after the treatment with different doses of ultraviolet irradiation (P<0.01). Tyrosinase activity was increased after different doses of ultraviolet irradiation(P<0.05). Melanin level of melanocytes was increased as compared with that of control group after 100mJ/cm2 of ultraviolet irradiation (P<0.01). Messenger RNA expression of WIF-1 was reduced as compared with that of control group after 100mJ/cm2 of ultraviolet irradiation (P<0.01). Messenger RNA expression of WNT5A, JNK, MITF, RAC1 and TYR was increased as compared with the control group after 100mJ/cm2 of ultraviolet irradiation(P<0.05). Protein expression of WIF-1 became lower than that of control group after 100mJ/cm2 of ultraviolet irradiation.Protein expression of WNT5A, JNK, MITF, RAC1 and TYR became higher than those of control group after 100mJ/cm2 of ultraviolet irradiation. Proliferation and activity of melanocytes were increased after 10-3mol/L to 10-3mol/L 17β-estradiol stimulation (P<0.01). Tyrosinase activity and melanin level of melanocytes were increased after 17β-estradiol stimulation (P<0.01). Messenger RNA expression of WIF-1 was increased as compared with the control group after 10-9mol/L of 17β-estradiol stimulation (P<0.01). Messenger RNA expression of JNK, MTTF and RAC1 was decreased as compared with the control group after 10-9mol/L of 17β-estradiol stimulation (P<0.01). Messenger RNA expression differences of WNT5A and TYR was not statistically significant as compared with the control group(P>0.05). Protein expression of WNT5A, WIF-1 and TYR became higher than that of control group after 10-9mol/L of 17β-estradiol stimulation. Protein expression of MITF, JNK and RAC1 became lower than that of control group after 10-9mol/L of 17β-estradiol stimulation.Conclusion Ultraviolet radiation reduces the proliferation and activity of melanocytes, increases tyrosinase activity and melanin level of melanocytes.17β-estradiol could increase proliferation, tyrosinase activity and melanin level of melanocytes. Non-classical wnt pathway plays an important role in the regulation of 17β-Estradiol and ultraviolet radiation on melanocyte melanogenesis. WIF-1 gene may inhibiting melanogenesis. The low expression of WIF-1 gene, by the effects of the non-classical pathway wnt proteins, activate JNK/MITF/TYR pathway, may ultimately promote the synthesis of melanin.Section 2 Cross-sectional study on etiology, aggravating factors and the influence to quality of life of patients with melasmaObjective To investigate on the etiology, aggravating factors, severity of melasma and its impact on quality of life in patients with melasma.Methods Clinical data of 166 female patients with melasma were collected through a questionnaire. The questionnaire covered the information concerning demographic characteristics, behaviours, and clinical evaluation of melasma. The score of melasma area severity index (MASI), dermatology life quality index (DLQI) and melasma quality of life scale (MELA-SQOL) were also be analyzed. The risk factors that influence melasma severity and quality of life in patients were determined by multiple linear regression analysis.Results Fifty-five patients had a history of pregnancy within 1 year before the onset of melasma. Eight patients had a history of sun exposure within 1 year before the onset of melasma. One hundred and three people have poor quality of sleep which lead to the aggravation of lesions. The patients’ score of MASI was 5.99±4.01, the score of DLQI was 4.34±4.41 and the score of MELA-SQOL was 30.54±.91. The score of MELA-SQOL was decreased with the growth of age, increased as the color of the lesions become deeper (P<0.05). The score of MELA-SQOL had no effects on the score of MASI. The score of MASI increased with age increasing and patients of Fitzpatrick skin type Ⅳ had a higher MASI score than patients of Fitzpatrick skin type Ⅲ did (P<0.05).Conclusion The etiologies of melasma have relationships with hormone levels fluctuate and sun exposure. Sleep loss and poor sleep quality are major causes of melasma aggravation. Younger patients with darker skin lesions have their quality of life affected by melasma heavier. The melasma severity of patients with Fitzpatrick skin type Ⅳ are higher than patients with Fitzpatrick skin type Ⅲ. Melasma patients’ lesions have an aggravating trend as age increasing before menopause.
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