Recovery Of Olfactory Sensory Neurons After Damage Involves Changes In Proliferation Patterns
The ability of lower vertebrates to regenerate entire organs is an intriguing phenomenon that has various beneficial implications for improving human health. Zebrafish have shared and conserved features with mammals, making them an ideal model to study regeneration. Intranasal irrigation with Triton X-100 produces severe degeneration of the olfactory epithelium, followed by rapid regeneration. We hypothesize that following chemical lesioning of the olfactory epithelium there will be changes in proliferation patterns that lead to recovery of the epithelium. Adult zebrafish were intraperitoneally injected with 50 L/g body weight of BrdU, and the right naris was irrigated with TX-100. Anti-BrdU was used to label newly born cells. In control fish, scattered BrdU+ profiles were present deep in the epithelium of the trough region, with few profiles in the side regions of the olfactory organ. One day after TX-100 treatment, there was obvious thinning of the epithelium; many BrdU+ profiles were observed in the trough region, with very few in the side region. By three days, the epithelial thickness appeared to return to control level; BrdU+ profiles were observed at various levels of the olfactory epithelium in both the trough and side regions. This appears to be evidence of differentiation and migration of olfactory sensory neurons. At five and seven days, BrdU profile numbers were substantially diminished, even below controls levels. Further investigation will focus on understanding the mechanisms involved in regenerating neurons after damage, with an overall goal of facilitating recover from neurodegenerative diseases and traumatic brain injuries.