Wang Ruiyan, Liu Wei, Gu Weijie, Zhang Ping
Department of Dermatology, Xijing Hospital, the Fourth Military Medical University, Xi'an, China.
Photomed Laser Surg. 2011 Oct;29(10):685-90. doi: 10.1089/pho.2011.3006. Epub 2011 May 19.
The purpose of this study was to evaluate the influence of intense pulsed light (IPL) irradiation on 8-methoxypsoralen plus ultraviolet-A irradiation (PUVA)-induced senescence of fibroblasts in vitro.
Exposure to PUVA may result in stress-induced senescence in fibroblasts. IPL has been widely used to treat photo-aged skin, but the mechanism is not clear.
The expression of senescence-associated β-galactosidase (SA-β-gal) was determined by histochemical staining, cell viability was assessed via an MTT assay, telomere length was determined by real-time polymerase chain reaction (PCR), and changes in the generation of reactive oxygen species (ROS) were determined by flow cytometry (FCM).
In comparison with the control cells, cells irradiated with PUVA and PUVA+IPL showed a general elevation in SA-β-gal activity (p<0.05). The number of SA-β-gal-positive fibroblasts in the PUVA+IPL group was clearly lower than that in the PUVA group (p<0.05). Cell viability showed a time-dependent decrease in both the PUVA and PUVA+IPL groups, in comparison with the viability in the control group, and there was no difference in viability between the PUVA and PUVA+IPL groups. PUVA treatment shortened telomere length and increased the level of ROS, in comparison with the corresponding findings for the control cells (p<0.05), whereas irradiation with IPL after PUVA exposure prevented telomere shortening and decreased the ROS level, in comparison with PUVA treatment only (p<0.05).
PUVA treatment induced fibroblast senescence, and irradiation with IPL after PUVA exposure partially rejuvenated the cells, demonstrating a protective effect against PUVA-induced fibroblast senescence.
本研究旨在评估强脉冲光（IPL）照射对8-甲氧基补骨脂素加紫外线A照射（PUVA）诱导的成纤维细胞体外衰老的影响。
暴露于PUVA可能导致成纤维细胞应激诱导的衰老。IPL已被广泛用于治疗光老化皮肤，但其机制尚不清楚。
通过组织化学染色测定衰老相关β-半乳糖苷酶（SA-β-gal）的表达，通过MTT法评估细胞活力，通过实时聚合酶链反应（PCR）测定端粒长度，并通过流式细胞术（FCM）测定活性氧（ROS）生成的变化。
与对照细胞相比，用PUVA和PUVA+IPL照射的细胞SA-β-gal活性普遍升高（p<0.05）。PUVA+IPL组中SA-β-gal阳性成纤维细胞的数量明显低于PUVA组（p<0.05）。与对照组相比，PUVA组和PUVA+IPL组的细胞活力均呈时间依赖性下降，且PUVA组和PUVA+IPL组之间的活力无差异。与对照细胞的相应结果相比，PUVA处理缩短了端粒长度并增加了ROS水平（p<0.05），而与仅PUVA处理相比，PUVA暴露后用IPL照射可防止端粒缩短并降低ROS水平（p<0.05）。
PUVA处理诱导成纤维细胞衰老，PUVA暴露后用IPL照射可使细胞部分恢复活力，表明对PUVA诱导的成纤维细胞衰老具有保护作用。
