Reaktive Sauerstoffspezies und Gefäßdegeneration

Background: In the current considerations of the genesis of cardiovascular degeneration, reactive oxygen species (ROS) have come into focus as a potential key factor. Several models of nutritive and enzymatic approaches have tried to analyze its causative role; however, they are accompanied by systemic effects and unforeseeable interaction patterns. Objective: This study analyzed the photodynamic reaction (PDR) regarding its potential to initiate a focal, non-systemic impact of oxidative stress. The induced processes and results were characterized by comparing them with the current perception of atherosclerotic vascular degeneration. Material and methods: A PDR was applied to the infrarenal aorta of rats by the combination of rose bengal and a low-power laser. The rats in the ROS and control groups (each n = 5) where killed at six points of time. All specimens were analyzed regarding gross morphological changes as well as detailed cell composition and the dynamics of cell migration. Results: Contrary to the controls, the ROS groups displayed an initial thrombus formation that disappeared not later than at t = 8 days. After a period of morphological latency accompanied by a significantly increased matrix metalloproteinase (MMP) activity, the ROS-exposed area displayed a significant thickening of the media (p < 0,001) as well as a significant focal calcification (p < 0.01). This was accompanied by a focally reduced alpha-smooth muscle actin (alpha-SMA) expression. Conclusion: The PDR induces morphological short-term effects that disappear after not later than 8 days. After a latency period, certain aspects of an atherosclerotic degeneration were obvious. In contrast, key aspects, such as increased inflammation and foam cells were missing. Nevertheless, the established concept is a suitable model to investigate the role of ROS in vascular degeneration.