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) synthetase activity, was evaluated in a rat model of laryngeal injury induced by endotracheal 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. Activity of myeloperoxidase, a marker of neutrophil infiltration, was also markedly increased into the damaged tissue. Immunohistochemistry for nitrotyrosine, an index of nitrosative stress, showed an intense staining in the inflamed 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 nitrotyrosine immunoreactivity in the larynx. The results of this study suggest that poly (ADP-ribose) synthetase may play a role in the inflammatory process after laryngeal intubation and extubation, and administration of 3-aminobenzamide may be a beneficial therapeutic approach.