Perflubron (PFOB) protects cell monolayers against direct in vitro oxidative injury

Introduction: Oxidative stress is often implicated in the genesis of injury to living tissues, even though intact cells generally possess sophisticated antioxidant systems. PFOB attenuates oxidative lung injury in vivo, at least in part due to a decrease in free radical release by macrophages. We hypothesized that PFOB would also protect a biological system from direct injury by reactive oxygen species. Methods: Rat pulmonary artery endothelial cells (RPAECs) were grown to confluence on optical grade culture dishes using standard technique. Cells were labeled with a permeable intracellular probe containing dihydrochlorofluorescein-diacetate (DCFH-DA), activated by cytoplasmic esterases. The cells were exposed to PFOB or culture medium for 15 min, after which all PFOB was removed by a transfer pipette. The monolayers were washed with medium prior to introduction of a buffer containing H₂O₂ to induce oxidative stress. Changes in cell fluorescence were measured in a kinetic fashion using a confocal fluorescence microscope. The digital images were analyzed with dedicated software to measure the amount of oxidative stress experienced by each monolayer. Results: Values are means ± SEM.*p < 0.05 vs baseline, 1 p < 0.05 vs PFOB. Conclusions: PFOB attenuates oxidative injury to cell monolayers. We speculate that due to its high spreading coefficient, PFOB may act as a physical barrier against free radicals originated in the aqueous phase. The lipophilic PFOB could potentially alter cell membrane fluidity and confer some protection even after its removal. Supported, in part, by the American Lung Association- NY Affiliate, and by Alliance Pharmaceutical Corporation.