目的 探讨长波紫外线（ UVA ）对人皮肤成纤维细胞增殖及诱导型一氧化氮合酶（ inducible nitric oxide synthase ， iNOS ）表达的影响，探讨白藜芦醇对此影响的防护作用及其机制。 方法 5 J·cm^-2 UVA 照射原代培养的成纤维细胞后予以 0.01 ， 0.1 mmol·L^-1 浓度的白藜芦醇干预，四甲基偶氮唑盐 (MTT) 法检测细胞增殖活性，半定量逆转录聚合酶链反应（ RT-PCR ）和蛋白质印迹（ Western-blot ）方法检测细胞 iNOS mRNA 和蛋白的表达。 结果 UVA 辐射后成纤维细胞的增殖活性（ 0.345 ± 0.020 ）较正常对照组（ 0.581 ± 0.038 ）降低， iNOS mRNA/ 蛋白的表达水平［（ 0.834 ± 0.087 ） / （ 0.804 ± 0.021 ）］较正常对照组 ( 未见表达 ) 显著增加。 UVA 辐射后立即予以 0.01 或 0.1 mmol·L^-1 浓度的白藜芦醇处理发现成纤维细胞的增殖活性上升而 iNOS mRNA/ 蛋白的表达下调，与单独 UVA 辐射组相比，差异有统计学意义 (<>P<0.05) 。 结论 UVA 可抑制体外培养的真皮成纤维细胞的增殖，诱导 iNOS 的表达，而白藜芦醇对 UVA 辐射损伤的成纤维细胞有保护作用。

OBJECTIVE To study the effects of ultraviolet A(UVA) on the proliferation and iNOS gene expression of cultured human dermal fibroblasts in order to explore the protective effect of resveratrol and possible mechanism. METHODS Human skin fibroblasts were incubated with 0.01 or 0.1 mmol·L-1 resveratrol after exposure to 5 J·cm-2 UVA, the activity of fibroblasts was detected by MTT assay，iNOS mRNA/protein expressions were measured by RT-PCR and Western-blot analysis techniques. RESULTS After exposure to UVA, the activity of fibroblasts (0.345±0.020) was decreased compared to control group (0.581±0.038), iNOS mRNA/protein expression level in fibroblast [(0.834±0.087)/(0.804±0.021)] were enhanced compared with control group (no iNOS expression) (P<0.05). In addition, our results found that 0.01 or 0.1 mmol·L-1 resveratrol after UVA irradiation could promote activity of fibroblasts and down-regulate iNOS mRNA/protein expression compared to the UVA group (P<0.05). CONCLUSION UVA irradiation can inhibit the growth and induce the expression iNOS mRNA/protein of cultured dermal fibroblasts in vitro, while resveratrol has potential protective effects on cultured fibroblasts from UVA induced damage.