Maeda K, Tomita Y, Naganuma M, Tagami H
Shiseido Research Center, Yokohama, Japan.
Photochem Photobiol. 1996 Jul;64(1):220-3. doi: 10.1111/j.1751-1097.1996.tb02446.x.
Guinea pig skin becomes more pigmented following exposure to UV rays. This melanization was accompanied by enhanced intensity of tyrosinase-staining and increased number of tyrosinase-positive melanocytes (MELty+), with resultant enhancement of melanin synthesis. To clarify the regulatory mechanism for melanization following UV irradiation, organ-cultured guinea pig skins have been used to examine their melanogenic responses to exogenous stimulation. This organ culture system responded well to UV irradiation, by increasing melanogenic activity. Also, in this system, phospholipases (PL), arachidonic acid, interleukin-1 alpha and melanocyte-stimulating hormone, but not endothelin-1 or phosphatidylinositol-specific PLC (PI-PLC), stimulated melanogenesis to various extents as indicated by the number of MELty+ and morphological changes. Among them, the PLA2 and PLD were found to have a potent stimulatory property for melanocytes. They might affect melanocytes directly or indirectly through an effect on keratinocytes. These results suggest that PLA2 and PLD play a key role in epidermal hyperpigmentation after UV irradiation or inflammation.
豚鼠皮肤在暴露于紫外线后色素沉着增加。这种黑色素沉着伴随着酪氨酸酶染色强度增强以及酪氨酸酶阳性黑素细胞（MELty+）数量增加，从而导致黑色素合成增强。为了阐明紫外线照射后黑色素沉着的调节机制，已使用器官培养的豚鼠皮肤来检测其对外源刺激的黑素生成反应。该器官培养系统对紫外线照射反应良好，通过增加黑素生成活性来实现。此外，在该系统中，磷脂酶（PL）、花生四烯酸、白细胞介素-1α和促黑素细胞激素，但内皮素-1或磷脂酰肌醇特异性磷脂酶C（PI-PLC）不会，以MELty+数量和形态变化表明，在不同程度上刺激了黑素生成。其中，发现PLA2和PLD对黑素细胞具有强大的刺激特性。它们可能直接或通过对角质形成细胞的作用间接影响黑素细胞。这些结果表明，PLA2和PLD在紫外线照射或炎症后的表皮色素沉着过度中起关键作用。
