Cell death, phagocytosis, and neurogenesis in mouse olfactory epithelium and vomeronasal organ after colchicine treatment.

The cytotoxic agent colchicine induced apoptotic cell death in the mouse olfactory epithelium and vomeronasal organ. The terminal deoxynucleotidyl transferase-mediated biotinylated deoxyuridine triphosphate nick end labeling (TUNEL) method revealed the presence of many apoptotic bodies in the middle to basal region of the septal olfactory epithelium and vomeronasal organ near the boundary of the respiratory epithelium at 1 day after intraperitoneal (i.p.) injection of colchicine (4 mg/kg). In some areas of the nasal turbinates, massive apoptosis was observed in the olfactory epithelium. Electron micrographs showed that immature olfactory cells and globose basal cells were killed by the colchicine and had been phagocytized by the supporting cells and macrophages. In some areas of the nasal turbinates, mature olfactory cells were also killed, and thus only the supporting cells and horizontal basal cells remained in the epithelium. Bromodeoxyuridine (BrdU) labeling showed that regeneration occurred in the septum and vomeronasal organ at 4-6 days after colchicine treatment; however, there were no regenerated olfactory cells in some areas of the turbinates up to 30 days after colchicine treatment.