Protective effect of 3-aminobenzamide, an inhibitor of poly (ADP-ribose) synthetase, against laryngeal injury in rats

The effect of 3-aminobenzamide, an inhibitor of poly (ADP-ribose) synthetas e activity, was evaluated in a rat model of laryngeal injury induced by end otracheal intubation for 1 h. At 1 h after extubation, the laryngeal damage was characterized by areas of mucosal necrosis, submucosal edema, swelling of subglottic glands, and submucosal infiltration of inflammatory cells. A ctivity of myeloperoxidase, a marker of neutrophil infiltration, was also m arkedly increased into the damaged tissue. Immunohistochemistry for nitroty rosine, an index of nitrosative stress, showed an intense staining in the i nflamed larynx. Treatment with 3-aminobenzamide (10 mg/kg intraperitoneally ) significantly reduced the appearance of mucosal damage and was associated with a significant reduction of tissue myeloperoxidase activity and nitrot yrosine immunoreactivity in the larynx. The results of this study suggest t hat poly (ADP-ribose) synthetase may play a role in the inflammatory proces s after laryngeal intubation and extubation, and administration of 3-aminob enzamide may be a beneficial therapeutic approach.