Colchicine-induced ciliated vacuoles in tracheal mucosa

In most cells the microtubules are destroyed and disappear after administration of colchicine in concentrations as low as 10(-6) M; colchicine inhibits the polymerization of tubulin and destroys the microtubules. Ciliary microtubules have resistance to colchicine but can, on the other hand, be destroyed by high concentrations of colchicine. In this study, we treated rabbits with considerably high concentrations (10 or 20 mg/100 g body weight) of colchicine for four successive weeks and examined the effects on the tracheal cilia. Abdominal administration of colchicine did not affect the morphology and structure of the cilia projecting on the cellular surface. However, ciliated vacuoles were observed in tracheal epithelial cells of rabbits treated with colchicine. The occurrence of such ciliated vacuoles depended on the dosage of colchicine: 2.4 +/- 0.4 per 100 microns epithelial length when treated with 10 mg/100 g body weight of colchicine, and 3.8 +/- 0.3 per 100 microns epithelial length when treated with 20 mg/100 g body weight. Some cilia present in ciliated vacuoles were pathological. In conclusion, a considerably high dosage of colchicine can inhibit ciliary microtubules during ciliogenesis, resulting in ciliated vacuoles.