Department of Dermatology, Inha University School of Medicine, Incheon, South Korea.
J Eur Acad Dermatol Venereol. 2012 Dec;26(12):1577-80. doi: 10.1111/j.1468-3083.2011.04223.x. Epub 2011 Sep 20.
Some of chronic hyperpigmentary diseases, such as melasma, induced by multiple factors including chronic sunlight exposure, can recur even after chemical epidermal removal. Dermal factors may be involved in the pathogenesis of melasma. Changes in dermal fibroblasts resulting from chronic sun exposure might cause melanocytes to synthesize melanin in the epidermis.
This study aimed at determining the effects of repetitive ultraviolet (UV) radiation on cultured fibroblasts and the secretion of melanogenic factors.
Cultured human fibroblasts were exposed to ultraviolet A (UVA) or ultraviolet B (UVB) for five consecutive days. After each irradiation, the supernatant medium was isolated from each dish and measured for levels of stem cell factor (SCF) and hepatocyte growth factor using an ELISA kit assay. To assess the effect of the keratinocyte-derived factors on fibroblast-secretion of SCF and hepatocyte growth factor, we added supernatants of the UV-irradiated keratinocytes to the non-irradiated fibroblasts. Finally, the irradiated fibroblasts were stained with senescence associated-β-galactosidase to assess their senescent change.
Fibroblasts irradiated with UVA or UVB for five consecutive days, secreted SCF at levels that increased with repeated UVA or UVB exposure. Conditioned culture medium from UV-irradiated keratinocytes also induced SCF release from fibroblasts, depending on the number of UV exposures. UVA- or UVB-irradiated fibroblasts stained positive for senescence associated-β-galactosidase, and the staining intensity increased with repeated exposure.
These results suggest that fibroblast senescence and increased SCF secretion after repeated UV irradiation may be related to the pathogenesis of recurring hyperpigmentation disorders induced by chronic sun exposure.
一些慢性色素沉着性疾病，如由多种因素引起的黄褐斑，包括慢性阳光暴露，即使在化学表皮去除后也会复发。真皮因素可能参与黄褐斑的发病机制。慢性阳光暴露引起的真皮成纤维细胞的变化可能导致黑素细胞在表皮中合成黑色素。
本研究旨在确定重复紫外线（UV）辐射对培养的成纤维细胞和黑色素生成因子分泌的影响。
将培养的人成纤维细胞暴露于长波紫外线 A（UVA）或中波紫外线 B（UVB）中连续 5 天。每次照射后，从每个培养皿中分离上清液，并使用 ELISA 试剂盒测定干细胞因子（SCF）和肝细胞生长因子的水平。为了评估角质形成细胞衍生的因子对成纤维细胞分泌 SCF 和肝细胞生长因子的影响，我们将经紫外线照射的角质形成细胞的上清液添加到未照射的成纤维细胞中。最后，用衰老相关-β-半乳糖苷酶染色来评估照射后的成纤维细胞的衰老变化。
连续 5 天用 UVA 或 UVB 照射的成纤维细胞，分泌的 SCF 水平随重复 UVA 或 UVB 暴露而增加。来自紫外线照射的角质形成细胞的条件培养基也可诱导成纤维细胞释放 SCF，这取决于紫外线照射的次数。UVA 或 UVB 照射的成纤维细胞染色为衰老相关-β-半乳糖苷酶阳性，并且随着重复暴露，染色强度增加。
这些结果表明，重复紫外线照射后成纤维细胞衰老和 SCF 分泌增加可能与慢性阳光暴露引起的复发性色素沉着障碍的发病机制有关。
