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Updated: Aug 7, 2026
Transplantation of Olfactory Ensheathing Cells to Evaluate Functional Recovery after Peripheral Nerve Injury
Published on: February 23, 2014
[Apoptosis of olfactory receptor neurons induced by bulbectomy]
Yu-rong Gu1, Hua-wei Li, Chong-hua Zhang
1Department of Otorhinolaryngology, Eye Ear Nose & Throat Hospital, Fudan University, Shanghai, China. yuronggu@eent.shmu.edu.cn
Objective:
To study whether apoptosis plays a role in controlling the number of olfactory receptor neurons, so as to reveal the specialty and mystery of neurogenesis.
Methods:
Using terminal deoxynucleotidyl transferase-mediated dUTP-fluorescein nick end labeling (TUNEL) and transmission electron microscopy to detect apoptosis in olfactory mucosa of normal adult rats and damaged olfactory mucosa of 16, 32, 48 hours and 3, 7, 30 days after bulbectomy.
Results:
In normal olfactory epithelium, a subpopulation of immature neurons, as well as mature neurons, showed internucleosomal DNA-fragmentation. The number of TUNEL-labeled neurons increased dramatically 32 hours after removal of olfactory bulb. Then it declined quickly and remained at low level. Ultrastructural data of olfactory mucosa showed that the feature of apoptotic neurons was chromatin condensation and cell shrinkage. Besides, some dying cells were characterized by the formation of numerous autophagic vacuoles, and few had some of the features of necrosis but without obvious mitochondrial swelling.
Conclusions:
Apoptosis might play a role in turnover of the olfactory epithelium and regeneration in adult rats. There might be other two types of neural death through different mechanism.
Insights
Apoptosis, programmed cell death, is crucial for regulating olfactory receptor neuron numbers during regeneration in adult rats. This study reveals programmed cell death as a key factor in olfactory system renewal.
Area of Science:
- Neuroscience
- Cell Biology
Context:
- The olfactory epithelium undergoes continuous neurogenesis throughout life.
- Understanding the mechanisms controlling neuron number is vital for comprehending olfactory system function and regeneration.
Purpose:
- To investigate the role of apoptosis in regulating olfactory receptor neuron populations.
- To elucidate the mechanisms of neural death during olfactory neurogenesis and regeneration.
Summary:
- This study utilized TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP-fluorescein nick end labeling) and electron microscopy to examine apoptosis in rat olfactory mucosa after bulbectomy.
- Results indicated that apoptosis occurs in both mature and immature olfactory neurons, with a significant increase observed 32 hours post-bulbectomy, followed by a decline.
- Ultrastructural analysis revealed characteristic features of apoptotic cells, including chromatin condensation and cell shrinkage, with some cells exhibiting autophagic vacuoles or features of necrosis.
Impact:
- The findings suggest that apoptosis plays a significant role in the turnover and regeneration of the olfactory epithelium in adult rats.
- The study hints at the existence of alternative neural death pathways distinct from classical apoptosis and necrosis.
