Effects of Carbocysteine on the Experimental Chronic Sinusitis Caused by Long-Term Exposure of So2

Abstract

The effects of SO2, one of main factors of air polution, on the nasal mucosa and tracheobronchial mucosa have been relatively well studied, but those on paranasal sinus have been little elucidated.In the present study, the pathology of the sinus mucosa induced in rabbits by exposure to 10 ppm of SO2, 4 hours a day for 4 successive weeks was studied from both functional and morphological point of view. In addition, the effects of carbocysteine given orally on the SO2-induced sinus mucosal disorder was studied.The following results were obtained from the present observations; 1) 24 hours after the final exposure to SO2, the sinus mucosa showed advanced disorder such as formation of compound cilia, vacuolation of epithelial cells, and partial fall-off of epithelial cells.2) The mean ciliary activity at the sinus mucosa 24 hours after the withdrawal of exposure was about 390 beats/min, declined moderately.3) Even 2 weeks after the withdrawal of the exposure, the ciliary activity was declined with a value of 570 beats/min, and epithelial cells showed morphological disorder.4) The ciliary activity and the morphology of the sinus mucosa in rabbits given 200 mg/kg of carbocysteine during or after the exposure to SO2 were almost normal.The results suggested that 1) The exposure to 10 ppm SO2 for 4 hours a day, 7 days a week, for 4 weeks in rabbits induces the pathological sinus mucosa similar to that of human chronic sinusitis; 2) SO2-induced sinus mucosal disorder is a useful model to preclinically study the effects of medical agents for treatment of chronic sinusitis, because being hardly recovered;3) Carbocisteine could be useful as a drug to treat chronic sinusitis.