gms | German Medical Science

Objectives/Interrogation: Dupuytren's disease is characterized by an increased proliferation and differentiation of fibroblasts to myofibroblasts, which provides an enhanced expression of alpha Smooth Muscle Actin (alpha-SMA). alpha-SMA modulates the contraction of fibrotic nodules and cords of the palmar aponeurosis. In prior studies, we could already demonstrate, that exposure of myofibroblasts to blue light reduces alpha-SMA-expression and subsequently contraction of the palmar aponeurosis. Reason for this phenomenon seems to be increased concentrations of reactive oxygen species (ROS) due to photobiomodulation with blue light. Aim of this study was to examine how far exposure with blue light leads to higher concentrations of ROS. Moreover, the influence of ROS-concentrations on alpha-SMA-expression and on ROS-modulating enzymes like catalase and Manganese Superoxide Dismutase (M-SOD) as well as on the transcriptional factor Nuclear Factor-kB (NF-kB) was detected.

Methods: Isolation and cultivation of fibroblasts from palmar aponeurosis tissue of patients with Dupuytren's Disease (n=7) as well as from carpal tunnel tissue (CTS, n = 7), as control group, was ensued. Differentiation of fibroblasts to myofibroblasts was established by dispensation of Transforming Growth Factor beta (TGF-beta). LED-Arrays that emit at wavelength of 453 nm (40 Joule, 38 mW/cm2) were used for irradiation with blue light. Expression of catalase, alpha-SMA, NF-kB and Mn-SOD were detected by western blot analysis.

Results and Conclusions: In both experimental groups, exposure to blue light lead to decreased expressions of catalase, Mn-SOD and tendentially reduced levels of NF-kB. Moreover, augmentation with hydrogen peroxide showed a reduced alpha-SMA expression. This suggests, that the therapeutic benefit of decreased alpha-SMA expression by blue light treatment could be modulated by ROS concentrations, especially by hydrogen peroxide levels. Our results demonstrate that decreased expressions of catalase through blue light exposure appears to be the cause for higher ROS- concentrations and seems to participate relevantly in pathophysiological mechanisms as well as therapeutic options in Dupuytren' s disease.