Adenovirus-mediated gene transfer in olfactory epithelium and olfactory bulb: a long-term study.

OBJECTIVES: We sought to study the spatiotemporal gene expression mediated by adenoviral vector in the olfactory pathways.
METHODS: The replication-defective adenoviral vector AxCALacZ, which encodes the enzyme Escherichia coli beta-galactosidase, was applied to mouse olfactory epithelium by intranasal instillation.
RESULTS: The LacZ gene product, beta-galactosidase, was expressed not only in the olfactory receptor neurons and their axons, but also in the olfactory bulbs. The first evidence of anterograde labeling was observed at postinfection day (PID) 2. At PID 3, beta-galactosidase was strongly expressed in olfactory nerve axons, as well as their terminal glomeruli, in the olfactory bulbs. beta-Galactosidase expression persisted up to PID 90, and there was a significant decrease in the number of labeled neurons at PID 30.
CONCLUSIONS: These results suggest possible long-term effects of adenovirus-mediated gene transfer on the olfactory neurons, as well as the olfactory bulbs.