中文摘要：

目的：观察两种皮肤细胞即原代黑素细胞（MC）与角质形成细胞（KC）对中波紫外线（UVB）辐射的反应差异。方法：采用不同剂量（0、30、60、90、120mJ／cm^2）UVB照射上述两种细胞，评估UVB对细胞作用的时间及剂量效应，以倒置光学显微镜观察细胞受损程度，细胞记数法记录生长曲线，MTT法检测细胞活性。结果：UVB照射后，KC的形态学改变、生长曲线及细胞活性的损伤程度随照射剂量加大而加重；MC在较低剂量时无明显受损，但达到一定剂量后其损伤程度亦随照射剂量加大而加重。另经30ml／cm^2照射孵育24h、48h及72h后，分别对两种细胞进行不同时间段的细胞活性比值比较（72h／48h，72h／24h），发现KC活性比依次递减（分别为1．81和1．23）；MC的活性比则相反（分别为0．94和1．01）。结论：低剂量UVB照射后，MC无形态学受损，其细胞突起增多，活性增强；较高剂量UVB照射后，MC和KC均有不同程度受损，KC的损伤程度随孵育时间延长而加重，而MC仍可在48h得到恢复。

英文摘要：

Objective To investigate and compare effects of UVB on human primary melanocytes and keratinocytes. Methods Two kinds of above cells were irradiated with different dosages of UVB and/or were cultured for different intervals. Light microscopy was used for morphological change, cell count and MTT were used to detect their proliferation and cellular activity. Results Compared with controls, UVB-irradiated keratinocytes were damaged morphologically, cell growth was inhibited and cellular activity decreased doseand time-dependently. On the contrary, no obvious damage happened to melanocytes when low-dosage UVB was administrered. However, their cellular activity got even stronger. But with the increase of UVB dosage, They also showed similar effects to those of keratinocytes. In addition, The cellular activity ratios calculated from various intervals after low-dosage UVB irradiation （72h/48h and 72h/24h ） were reversed between the 2 cells. The MTT ratio showed a decrease in keratinocytes（1.81 and 1.23）, while an increase in melanocytes（0.94 and 1.01）. Conclusion The photodamage on keratinocytes and melanocytes induced by UVB irradiation shows quite different. Melanocytes show a stronger resistant ability to UVB irradiation compared with keratinocytes.