中文摘要：

目的：研究西罗莫司诱导自噬对UVB致HaCaT细胞光损伤的干预作用。方法：设置6组，分别为空白组、二甲基亚砜（DMSO）组、25mJ／cm2UVB组、25mJ／cm2UVB＋西罗莫司组、50mJ／cm2UVB组、50mJ／cm2UVB＋西罗莫司组。单丹（磺）酰戊二胺（MDC）法检测不同处理后HacaT细胞的自噬并比较各组自噬水平。噻唑蓝（Myr）法检测不同处理后HaCaT细胞的增殖活性。Hochest、碘化丙啶（PU染色观察HaCaT细胞的凋亡和坏死。结果：MDC染色结果可见西罗莫司处理组的自噬体阳性细胞百分率分别高于相应UVB照射组。MTr法检测到25mJ／cm2UVB＋西罗莫司组的细胞增殖抑制率低于25mJ／cm2UVB组，而50mJ／cm2UVB＋西罗莫司组高于50mJ／cm2UVB组。Hochest染色观察到西罗莫司处理组的凋亡百分率分别低于相应UVB组。PI染色可见UVB照射组出现坏死细胞，而西罗莫司干预组未见坏死细胞。结论：西罗莫司诱导自噬可减轻25mJ／cmzUVB辐照对HaCaT细胞增殖能力的抑制，而在50mJ／cmzUVB辐照下加重对细胞的抑制。西罗莫司诱导自噬可明显减轻25、50mJ／cm2UVB辐照下HaCaT细胞的凋亡和坏死，对UVB损伤有保护作用。

英文摘要：

Objective： To study the effects of sirolimus-induced autophagy on UVB-irradiation induced HaCaT cell damaged. Methods： HaCaT cells were divided into 6 groups, each of which was treated with vehicle, sirolimus, UVB or combination of sirolimus and UVB. MDC and MTT assays were used to measure cell autophagosome levels and proliferation respectively. Apoptosis and necrosis in HaCaT cells were assessed by Hoechest and PI staining respectively. Results： The percentage of the autopagosome-positive cells in sirolumus treated group was higher than that in UVB irradiated cells. In comparison with U- VB irradiation alone, combination of sirolimus and 25 mJ/cm2 UVB irradiation induced less inhibition of proliferation. In corn parison with 50 mJ/cm2 UVB irradiation alone, combination of sirolimus and 50 mJ/cm2 UVB irradiation induced a higher growth inhibition rate. Hoechest staining showed that apoptosis rate in sirolimus-treated cells was lower than that in UVB irradiated cells. Moreover, no necrotic cells were seen in sirolimus-treated groups while some necrotic ceils were observed following UVB irradiation. Conclusions： Sirolimus induced autophagy can attenuate HaCaT cell growth inhibition caused by 25 mJ/cm2 UVB irradiation. In contrast, sirolimus enhances growth inhibition induced by 50 mJ/cm2 UVB irradiation. Sirolimus induced au- tophagy can decrease HaCaT cell apoptosis and necrosis induced by UVB irradiation at the doses of 25 or 50 mJ/cm2, and protect HaCaT ceils against UVB irradiation.