Paz Mariela L, González Maglio Daniel H, Weill Federico S, Bustamante Juanita, Leoni Juliana
Institute of Immunology, School of Pharmacy and Biochemistry, University of Buenos Aires, Buenos Aires, Argentina.
Photodermatol Photoimmunol Photomed. 2008 Jun;24(3):115-22. doi: 10.1111/j.1600-0781.2008.00348.x.
Ultraviolet (UV) radiation is the major environmental harmful factor that affects human skin. UVB radiation is known to be a potent inducer of reactive oxygen species (ROS) production and has also been associated with the generation of nitric oxide (NO), all of which have been implicated in various skin disorders. It is well known that mitochondria can also be affected by UVB, leading to alterations in their membrane structure and permeabilization with cytochrome c release, which consequently affects the cell function. However, the loss of keratinocyte mitochondrial function generated by UVB, as well as its kinetics, has not been characterized completely.
We evaluated the effect of UVB irradiation on HaCat cells' mitochondrial function, assessed by membrane potential loss and superoxide anion (O(2)(*-)) production, correlating with apoptosis, p53 expression, ROS levels and NO production, 0, 6, 12, 24 and 48 h post-irradiation.
HaCat cells progressed toward apoptotic cell death as the time post-irradiation increased, with the highest levels found 48 h after irradiation. Increased levels of ROS were observed 6 h after irradiation while high O(2)(*-) levels and mitochondrial membrane depolarization were detected 12 h post-UVB. Nevertheless, NO production was not significantly increased at any of the evaluated times.
The kinetics of mitochondrial dysfunction after UVB irradiation in human keratinocytes progressed in a time post-irradiation-dependent manner, and they are closely related to cell death. However, there are certain levels of apoptosis, although low, in the absence of mitochondrial alterations. In addition, our data suggest that ROS play a greater role in keratinocyte UVB damage than reactive nitrogen species.
紫外线（UV）辐射是影响人类皮肤的主要环境有害因素。已知UVB辐射是活性氧（ROS）产生的强效诱导剂，并且还与一氧化氮（NO）的生成有关，所有这些都与各种皮肤疾病有关。众所周知，线粒体也会受到UVB的影响，导致其膜结构改变和细胞色素c释放引起的通透性改变，从而影响细胞功能。然而，UVB引起的角质形成细胞线粒体功能丧失及其动力学尚未完全明确。
我们评估了UVB照射对HaCat细胞线粒体功能的影响，通过膜电位丧失和超氧阴离子（O(2)(*-)）产生来评估，并将其与照射后0、6、12、24和48小时的细胞凋亡、p53表达、ROS水平和NO产生相关联。
随着照射后时间的增加，HaCat细胞逐渐走向凋亡性细胞死亡，在照射后48小时达到最高水平。照射后6小时观察到ROS水平升高，而在UVB照射后12小时检测到高O(2)(*-)水平和线粒体膜去极化。然而，在任何评估时间NO产生均未显著增加。
人角质形成细胞在UVB照射后线粒体功能障碍的动力学呈照射后时间依赖性进展，并且它们与细胞死亡密切相关。然而，在没有线粒体改变的情况下存在一定程度的细胞凋亡，尽管程度较低。此外，我们的数据表明ROS在角质形成细胞UVB损伤中比活性氮发挥更大的作用。
