Effect of theophylline on vascular tissue in a model of oxidative stress induced by titanium dioxide nanoparticles

This study aimed to test the antioxidant effects of prophylactic low dose Theophylline against oxidative stress in rat aorta induced by a single acute dose of dioxide titanium nanoparticles (TiO2-NPs). Seventy-two adult Wistar male rats were allocated in four experimental groups (n = 18): control (saline solution, i.g.), Theophylline (2 mg/kg for 5 days, ig), TiO2-NPs (5 mg/kg, single dose, i.v.), and Theophylline+TiO2-NPs (2 mg/kg i.g. for 5 days, and then 5 mg/kg i.v., single dose, respectively). Oxidative stress biomarkers such as lipoperoxides, carbonyls, reduced glutathione (GSH) in homogenates of aorta were evaluated; systolic blood pressure, diastolic blood pressure, mean blood pressure and histology of aorta were also evaluated at three experimental times (12, 24 and 168 h post treatments). In oxidative stress tests, TiO2-NPs increased the levels of lipoperoxides (174%) and carbonyls (132%), while decreased the levels of GSH (48%) compared to control group. The levels of systolic blood pressure (45%), diastolic blood pressure (46%) and mean blood pressure (46%) increased compared to control group. Theophylline group maintained lipoperoxides, carbonyls, systolic blood pressure, diastolic blood pressure and mean blood pressure at levels similar as control levels. In the histologic test TiO2-NPs group demonstrated signs of rippling that suggest contraction in vascular muscle, these results were not observed in Theophylline+TiO2-NPs, where it showed similar results to control group. Results in this study suggest that low dose Theophylline protects in a prophylactic way the aorta against oxidative stress induced by a single dose of TiO2-NPs.