中文摘要：

目的探讨西罗莫司能否增加中波紫外线（UVB）照射下HaCaT细胞的自噬水平。方法0、25、50mJ／cm^2 UVB照射HaCaT细胞，单丹（磺）酰戊二胺（MDC）染色法检测自噬。设置空白组、DMSO组、25mj／cm^2 UVB组、25mJ／cm^2 UVB＋西罗莫司组、50mJ／cm2UVB组、50mJ／cm^2 UVB＋西罗莫司组共6组，MDC染色法检测自噬，并比较各组自噬水平。结果结果UVB照射HacaT细胞后出现了自噬，0、25、50mJ／cm^2照射组自噬体阳性细胞分别为1．07％±1．85％、9．37％±1．14％、16．29％±3．03％，3个剂量间差异有统计学意义；6组自噬体阳性细胞百分率分别为：0．56％±0．79％、1．61％±2．27％、10．00％±0．47％、21．18％±3．03％、15．82％±4．13％、29．45％±1．24％，各组两两比较差异均有统计学意义，且25mJ／cm^2 UVB＋西罗莫司组、50mJ／cm^2 UVB＋西罗莫司组的自噬水平均高于相应UVB组。结论UVB辐照HaCaT细胞后出现MDC染色自噬体阳性细胞，西罗莫司可能增加UVB照射下HaCaT细胞后的自噬水平。

英文摘要：

Objective To investigate whether sirolimus increases the autophagy level in HaCaT human keratinocytes induced by ultraviolet B （UVB） irradiation. Methods HaCaT cells were irradiated by UVB of 0, 25 and 50 mJ/cm2 respectively. After additional 6-hour culture, monodansylcadaverin （MDC） staining was carried out to detect autophagosomes in HaCaT cells. Then, some HaCaT cells were classified into 4 groups to be irradiated with UVB （25 and 50 mJ/cm2 respectively） alone or followed by sirolimus （10 nmol/L） treatment, those remaining untreated served as the blank control group, and those treated by dimethyl sulfoxide （DMSO） served as the DMSO group. The level of autophagy in these groups was determined by monodansylcadaverin （MDC） staining. Results Autophagy was detected in HaCaT cells after UVB irradiation. Significant differences were observed in the percentage of autophagosome-positive cells irradiated by UVB at O, 25 and 50 mJ/cm2 （1.07% ±1.85% vs. 9.37% ± 1.14% vs. 16.29%±3.03%, F= 37.34, P 〈 0.01）. The percentage of autophagosome-positive cells was 0.56% ± 0.79%, 1.61% ± 2.27%, 10.00% ± 0.47%, 21.18%± 3.03%, 15.82% ± 4.13% and 29.45% ± 1.24% in the blank control group, DMSO group, 25 mJ/cm2 UVB group, 25 mJ/cm2 UVB ＋ sirolimus group, 50 mJ/cm2 UVB group, 50 mJ/cm2 UVB ＋ sirolimus group, respectively （F = 45.23, P 〈 0.01 ）. Sirolimus significantly elevated the level of autophagy in HaCaT cells irradiated by UVB of 50 and 25 mJ/cm2. Conclusions Autophagosomes are observed in HaCaT cells irradiated by UVB. And sirolimus may upregulate the autophagy level in UVB-induced HaCaT cells.