Department of Biochemistry and Molecular Pathology, Osaka City University Medical School, Osaka, Japan.
Clin Exp Dermatol. 2011 Jan;36(1):52-6. doi: 10.1111/j.1365-2230.2010.03777.x.
Irradiation by ultraviolet (UV) initiates pigmentation of skin; however, it is not known whether changes in intestinal pigmentation are also induced by UVB irradiation of the eye.
To examine the influence of UVB irradiation of the eye or ear on the pigmentation of mouse epidermis and intestine.
DBA/2 male mice were locally exposed to UVB (280-320 nm) using a 20SE sunlamp directed at the eye or ear. The irradiation was given over 3 days, at a dosage of 2.5 kJ/m(2) per day. Five days after irradiation, samples were taken from the skin and intestine. Melanocytes in both epidermis and intestine were stained for dopa and expression of melanocortin-1 receptor (MC1R). Levels of plasma α-melanocyte-stimulating hormone (α-MSH) were measured using ELISA.
Ultraviolet B irradiation of either the eye or ear in increased the number of dopa-positive melanocytes in the skin and the intestine (jejunum and colon). Irradiation of the eye caused a much greater increase in dopa than did irradiation of the ear. Both eye and ear irradiation increased blood α-MSH level to a similar extent, but only irradiation to the eye increased MC1R expression in the intestine.
These results suggest that the UVB-induced pigmentation in the epidermis and the intestine is related to increased levels of α-MSH and MC1R.
紫外线（UV）辐射会引发皮肤色素沉着；然而，目前尚不清楚眼部 UVB 辐射是否也会引起肠道色素沉着的变化。
检查眼部或耳部的 UVB 辐射对小鼠表皮和肠道色素沉着的影响。
使用 20SE 太阳灯将 DBA/2 雄性小鼠的眼部或耳部定向局部暴露于 280-320nm 的 UVB 下。每天照射 3 天，剂量为 2.5kJ/m(2)。照射后 5 天，从皮肤和肠道取样。用多巴对表皮和肠道中的黑素细胞进行染色，并检测黑素皮质素-1 受体（MC1R）的表达。使用 ELISA 测量血浆 α-促黑素细胞激素（α-MSH）的水平。
眼部或耳部的 UVB 辐射均可增加皮肤和肠道（空肠和结肠）中多巴阳性黑素细胞的数量。眼部照射比耳部照射引起的多巴增加更多。眼部和耳部照射均使血液 α-MSH 水平增加到相似的程度，但只有眼部照射才能增加肠道中的 MC1R 表达。
这些结果表明，表皮和肠道中的 UVB 诱导的色素沉着与 α-MSH 和 MC1R 水平的增加有关。
