Effect of vitamin C on tracheal responsiveness and pulmonary inflammation in chronic obstructive pulmonary disease model of guinea pig

In the present study, the prophylactic effect of vitamin C, as a potent anti-oxidant, on tracheal responsiveness to methacholine and ovalbumin, bronchoalveolar lavage fluid white blood cell (WBC) count and differential count, and also lung pathology in chronic obstructive pulmonary disease (COPD) -guinea pigs (cigarette exposed guinea pigs) were examined. In addition, the relaxant effects of theophylline on tracheal chains of guinea pigs were studied. Twenty four male guinea pigs were randomly divided to three groups; control (C group), COPD model of guinea pigs (COPD group) and pretreated group (COPD+ Vit C group). The two first groups were given drinking water alone, and the third group used water containing vitamin C. The relaxant effects of four cumulative concentrations of theophylline were examined by their relaxant effects on precontracted tracheal chains of guinea pig by 60 mM KCl (group 1) and 10 μM methacholine (group 2). The tracheal responsiveness to methacholine and ovalbumine, and WBC count of COPD guinea pigs were significantly higher than those of controls (p<0.05 to p<0.001). The lung in COPD group showed significant pathological changes. The tracheal responsiveness to methacholine and avalbumine and WBC count were significantly decreased in pretreated group compared with the COPD guinea pigs (COPD group) (p<0.05 to p<0.001). In both groups, the relaxant effect of theophylline in the COPD group was lower than the control group (group C) (p<0.05 to p<0.001). These results showed prophylactic effect of vitamin C on tracheal responsiveness and pulmonary inflammation of COPD-guinea pigs.