OBJECTIVETo investigate the effect of bicyclol on vascular oxidative stress injury induced by superoxide anion.

METHODSRat thoracic aortic rings were isolated for isometric tension recording using organ bath technique. Superoxide arterial injury was induced by pyrogallol exposure, and the effect of bicyclol on endothelium-dependent relaxation was evaluated.

RESULTSBicyclol (10(-8) - 10(-5) mol/L) relaxed endothelium-intact aortic rings precontracted by phenylephrine. This effect was abolished by L-NAME, an inhibitor of nitric oxide synthase and indomethacin, an inhibitor of cyclooxygenase. Exposure to pyrogallol (500 micromol/L) resulted in decrease of acetylcholine(ACh)-induced endothelium-dependent relaxation in aortic rings, and pre-incubation of bicyclol (10(-5) mol/L) for 45 min improved the relaxation attenuated by pyrogallol. In aortic rings pre-treated with indomethacin, bicyclol increased the ACh-induced relaxation that was inhibited by pyrogallol (500 micromol/L). This effect was not found in aortic rings pre-treated with L-NAME.

CONCLUSIONBicyclol has endothelium-dependent vasodilating effect on rat thoracic aorta and improves vascular function by attenuating oxidative stress. Nitric oxide from endothelium is involved in the anti-oxidative effect of bicyclol.

Animals ; Antioxidants ; pharmacology ; Aorta, Thoracic ; metabolism ; physiology ; Biphenyl Compounds ; pharmacology ; Endothelium, Vascular ; physiology ; In Vitro Techniques ; Male ; Oxidative Stress ; drug effects ; Pyrogallol ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Superoxides ; pharmacology ; Vasodilation ; drug effects ; physiology