雌二醇及中波紫外线在豚鼠皮肤色素沉着形成中的作用及其机制

目的：研究雌二醇和中波紫外线( UVB)辐射对豚鼠背部棕色皮肤中黑素代谢的影响，探讨雌激素及UVB在皮肤色素沉着中的作用。方法选取健康花色豚鼠，设立溶媒对照组、UVB照射组、雌二醇处理组和雌二醇预处理后UVB照射组(雌二醇+UVB组)；雌二醇浓度设为3．67×10-5、3．67×10-4、3．67×10-3 mol/L；UVB 照射剂量统一为500 mJ/cm2。采用皮肤在体共聚焦激光扫描显微镜(简称皮肤CT)以及透射电子显微镜等观察雌二醇和UVB对黑素小体合成及降解的影响。结果①一定浓度雌二醇可加深豚鼠皮肤色素沉着，且随着雌二醇浓度的递增，沉着程度逐渐加深(P<0．05)。② UVB照射组豚鼠皮肤色素沉着较未照射组明显增加(P<0．05)。③ UVB照射后豚鼠表皮角质形成细胞中自噬体增加，而雌二醇处理后自噬体减少。结论雌二醇及UVB照射均可促进豚鼠皮肤色素沉着，其机制可能与促进黑素小体合成有关，黑素小体的降解异常也参与了豚鼠皮肤色素沉着的形成。

The effect and mechanism of estradiol and UVB radiation on pigmentation of guinea-pig skin

Objective To investigate the influence of estradiol and ultraviolet B ( UVB) radiation on melanin me-tabolism of guinea-pig’ s brown dorsal skin, and explore the relationship between the estrogen and ultraviolet in skin pigmentary disorder. Methods Healthy suit guinea-pigs were selected in this study. The guinea-pigs skin was di-vided into solvent control group, UVB irradiation group, estradiol treatment group and UVB irradiation after estradi-ol pertreatment group ( estradiol + UVB group) . The concentrations of estradiol were set to 3. 67 × 10 -5 ,3. 67 × 10 -4 ,3. 67 × 10 -3 mol/L. The UVB exposure dose was unified as 500 mJ/cm2 . In vivo confocal laser scanning mi-croscopy ( referred to as skin CT) and transmission electron microscopy were used to observe the effects of estradiol and UVB on melanin metabolism and degradation. Results ①The pigmentation of guinea-pig skin was deepened after a certain concentration of estradiol treatment, increased gradually with the increasing of estradiol concentration (P<0. 05). ② The pigmentation of guinea-pig skin was also deepened significantly in UVB irradiation group, compared with non-UVB irradiation group(P<0. 05). ③The autophagy of epidermal keratinocytes of Guinea pigs increased with UVB irradiation, but decreased with estradiol treatment. Conclusion Estradiol and UVB irradiation can promote pigmentation of guinea-pig skin and the mechanism may be related to the promotion of melanosomes synthesis. The degradation of abnormal melanosomes may also be involved in the formation of pigmentation.