COL-3 prevents intracellular oxidative stress generated in
microglial cells in response to inflammatory signals
To test the hypothesis of a ROS-dependent NADPH production, we used a
quantitative cell-based fluorescence assay to evaluate ROS in microglial
cells exposed to 10 ng/ml LPS or 70 µg/ml αSa (Figure 5). As expected, a
24-h treatment with LPS (10 ng/ml) or αSa (70 µg/ml) induced a
significant increase of intracellular ROS levels in microglial cells. In
contrast, αSm does not induce significant effects on ROS levels. Of
interest, ROS production returned to control values when cultures
exposed to either LPS or αSa were previously treated with 20 µM COL-3
(Figure 5A,B), confirming the hypothesis that the non-antibiotic
tetracycline may exert anti-inflammatory effects by counteracting
oxidative stress-dependent mechanisms. As expected, the inhibitory
effect of COL-3 on ROS production was mimicked by DOX at 50 µM.
Noticeably, the NADPH oxidase inhibitor APO (300 µM) and the antioxidant
TROL (10µM) reduced ROS production with an efficacy similar to that
demonstrated by COL-3.