Izykowska Ilona, Piotrowska Aleksandra, Podhorska-Okołów Marzena, Cegielski Marek, Zabel Maciej, Dziegiel Piotr
Katedra i Zakład Histologii i Embriologii Akademii Medycznej im. Piastów Slaskich we Wrocławiu.
Postepy Hig Med Dosw (Online). 2008 Jan 22;62:23-7.
Melatonin (Mel) is a hormone synthesized mainly by the pineal gland. The principal function of Mel in the body involves the control of circadian and seasonal rhythms. Moreover, numerous reports document its anti-oxidative properties. Skin and eyes are particularly sensitive to the noxious influences exerted by UV exposure. The most dangerous radiation of the UVB (ultraviolet-B) and UVA (ultraviolet-A) range induces the formation of reactive oxygen species and thus stimulates the apoptosis of exposed cells. In numerous in vivo and in vitro studies, Mel produced in the skin and eye has been found to protect against the sequelae of UVB- and UVA-induced oxidative stress. In in vitro studies involving UVB irradiation of keratinocytes, fibroblasts, and leukocytes, Mel applied in both pharmacological (10(-3) and 10(-4 )M) and physiological doses (10(-7) and 10(-9) M) decreased the fraction of damaged cells. A similar pattern of Mel action at various doses of Mel probably reflected the presence of melatonin receptors (mainly MT1 receptors) in skin and eye cells. Moreover, intraperitoneally administered Mel or Mel applied to the skin before UVB exposure protects against the development of cataract and erythema, respectively. Thus only intracellular Mel may protect cells against the effects of UVB exposure. Although there are numerous reports describing the effects of UVA on cells of the skin and eye, no studies have described the anti-oxidative properties of Mel in relation to UVA-irradiated cells.
褪黑素（Mel）是一种主要由松果体合成的激素。Mel在体内的主要功能涉及昼夜节律和季节节律的调控。此外，众多报告记录了其抗氧化特性。皮肤和眼睛对紫外线照射产生的有害影响特别敏感。UVB（紫外线B）和UVA（紫外线A）范围内最危险的辐射会诱导活性氧的形成，从而刺激受照射细胞的凋亡。在众多体内和体外研究中，已发现皮肤和眼睛中产生的Mel可保护免受UVB和UVA诱导的氧化应激的后遗症影响。在涉及角质形成细胞、成纤维细胞和白细胞UVB照射的体外研究中，以药理学剂量（10⁻³和10⁻⁴ M）和生理剂量（10⁻⁷和10⁻⁹ M）应用的Mel均降低了受损细胞的比例。不同剂量Mel的类似作用模式可能反映了皮肤和眼睛细胞中存在褪黑素受体（主要是MT1受体）。此外，腹腔内注射Mel或在UVB照射前将Mel应用于皮肤分别可预防白内障和红斑的发生。因此，只有细胞内的Mel可以保护细胞免受UVB照射的影响。尽管有许多报告描述了UVA对皮肤和眼睛细胞的影响，但尚无研究描述Mel对UVA照射细胞的抗氧化特性。
