Recovery following peripheral destruction of olfactory neurons in young and adult mice.
Olfactory neurons (ON) which are located in the olfactory epithelium are responsible of odorous molecule detection. A unique feature of these cells is their continuous replacement throughout life due to the proliferation and differentiation of local neural precursors, the basal cells. Thus, experimental destruction of all ON induces a stimulation of basal cell division followed by tissue regeneration. The fact that ON precursors display such proliferative and neurogenic activity in adults makes these cells particularly attractive as a potential tool for nervous system repair. However, basal cell proliferation and, thus, ON production, decrease in relation to age; mostly during the first months of life. Therefore, we aimed to seek whether the ability of ON precursors to yield new functional ON in regenerative conditions was consequently impaired in adult. ZnSO4 intranasal perfusion administered to young (1 month) and adult (6 months) mice leads in a few days to total ON destruction and to hyposmia. Tissue and function restoration occurred in the following weeks in both mice groups and was preceded by a transient peak of cell division. In adults, although neurogenesis in the impaired olfactory epithelium was less efficient than in young mice, neural precursors retain their ability to provide new functional ON as indicated by the butanol detection recovery. This was achieved more rapidly than total ON regeneration, suggesting that a reduced number of reconnected ON may be sufficient for odor discrimination.
Ducray
Angélique
A
Laboratoire de Neurosciences, EA 481, Université de Franche-Comté, Place Leclerc, 25030 Besançon.
Bondier
Jean-Robert
JR
Michel
Germaine
G
Bon
Karine
K
Millot
J L
JL
Propper
Alain
A
Kastner
Anne
A
D000375:Aging / Q000502:physiology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D002452:Cell Count; D002455:Cell Division / Q000187:drug effects / Q000502:physiology*; D003714:Denervation; D004193:Discrimination Learning / Q000187:drug effects / Q000502:physiology; D019922:GAP-43 Protein / Q000378:metabolism; D007150:Immunohistochemistry; D051379:Mice; D008815:Mice, Inbred Strains; D009410:Nerve Degeneration / Q000139:chemically induced / Q000503:physiopathology; D009416:Nerve Regeneration / Q000187:drug effects / Q000502:physiology*; D009833:Olfactory Pathways / Q000166:cytology / Q000254:growth & development* / Q000502:physiology; D018034:Olfactory Receptor Neurons / Q000166:cytology / Q000254:growth & development* / Q000502:physiology; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D020127:Recovery of Function / Q000187:drug effects / Q000502:physiology*; D012903:Smell / Q000187:drug effects / Q000502:physiology*; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*; D013936:Thymidine / Q000378:metabolism; D014316:Tritium; D019287:Zinc Sulfate
D019922:GAP-43 Protein; D018809:Proliferating Cell Nuclear Antigen; D014316:Tritium; D019287:Zinc Sulfate; D013936:Thymidine