Effects of reactive oxygen species scavengers on adipogenesis

Abstract

Reactive oxygen species (ROS) have been implicated in regulating adipogenesis. Lack of a thorough understanding of the interplay between ROS and adipogenesis has hampered efforts to develop effective therapeutic solutions for obesity and its comorbidities. Thus, this study was initiated to investigate the effects of ROS and the ROS scavengers Trolox and apocynin on adipogenic differentiation of adipose-derived stromal/stem cells (ASCs). ASCs are generally viewed as the cells of origin of adipocytes, therefore ASCs derived from human fat tissue samples were chosen as a model to study adipogenesis in vitro. ASCs were induced to differentiate in the presence and absence of ROS scavengers. ASCs were also induced to differentiate during exposure to exogenous hydrogen peroxide (H2O2) in the presence and absence of ROS scavengers. Quantification of adipogenic differentiation and intracellular ROS levels were done using flow cytometry while extracellular ROS release was determined using a spectrofluorimeter.

The results of this study showed that extracellular ROS (H2O2) treatment of ASCs accelerated adipogenesis with faster differentiation kinetics in cells that differentiated in the continuous presence of H2O2. However, the study showed that there was no extracellular ROS release during adipogenesis. Treatment of differentiating ASCs with Trolox had no effect on adipogenesis in the presence and absence of extracellular H2O2. There was also no corresponding change in total intracellular and mitochondrial ROS levels with Trolox addition to differentiating human ASCs. Addition of apocynin to differentiating ASCs also had no change in total intracellular and mitochondrial ROS levels. However, apocynin addition suppressed adipogenesis in ASCs that were pre-treated with H2O2 for 24 hours prior differentiation during the early phases of differentiation. This adipogenic inhibition effect was not associated with changes in total intracellular and mitochondrial ROS levels. These findings suggest that extracellular ROS pre-treatment possibly refines or influences the action of apocynin as an anti-adipogenic agent in differentiating ASCs. Thus, apocynin could be protective in conditions of oxidative stress where cells are exposed to ROS.

This study showed that Trolox has no effect on adipogenesis as well as on intracellular ROS levels in differentiating human ASCs. Apocynin was also shown to have no effect on intracellular ROS levels. However, the study demonstrated that apocynin could potentially be a useful anti- adipogenesis agent that can possibly find applications in the prevention or treatment strategies for obesity. The mechanisms involved during apocynin enhancement of adipogenic differentiation is however not clear and need further investigation.