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Optic Nerve Transection: A Model of Adult Neuron Apoptosis in the Central Nervous System
Published on: May 12, 2011
Apoptosis in relation to neuronal loss in experimental Creutzfeldt-Jakob disease in mice
D Jesionek-Kupnicka1, R Kordek, J Buczyński
1Department of Molecular Biology, Medical Academy, Łódź, 8/10 Czechoslowacka St., 92-216 Łódź, Poland.
Abstract:
Apoptosis constitutes a genetically determined process to eliminate superfluous or damaged cells in tissues. Deficiencies in apoptosis regulation are involved in different pathologies including prion diseases. Some experimental studies show that neuronal loss--one of the hallmarks of prion diseases may be accomplished by apoptosis. We evaluated twenty five mice infected experimentally with the Fujisaki strains of CJD and sacrified sequentially in one week intervals. Apoptotic cells in various brain regions were detected by in situ end labelling (TUNEL) and electron microscopy in comparison with neuronal cell loss. The number of labelled cells per brain was very low--from a few labelled cells 6 weeks after inoculation to a maximum of 14 in the terminal stage. The number of neurones counted in 8 selected areas were considerably lower in terminally sick animals (20 and 21 week of incubation period) than in control mice. The mean value of loss of neuronal cells was 32%. The greatest loss (55%) of neurones was noted in the septal nuclei of the paraterminal body and the least lost (16%) in the hypothalamus. Compared to the extensive neuronal loss (30-50%), the number of apoptotic cells detected by in situ end labelling seems to be very low, and the process of neuronal death become more intensive during the progression of the disease.
Insights
Apoptosis, programmed cell death, plays a role in prion diseases like Creutzfeldt-Jakob disease (CJD). While significant neuronal loss occurs, the study found very few apoptotic cells, suggesting other cell death mechanisms are involved.
Area of Science:
- Neuroscience
- Cell Biology
- Pathology
Background:
- Apoptosis is a crucial cellular process for tissue homeostasis.
- Dysregulation of apoptosis is implicated in various diseases, including neurodegenerative disorders.
- Neuronal loss is a key feature of prion diseases, with a potential role for apoptosis.
Purpose of the Study:
- To investigate the extent of apoptosis in the brain during experimental prion disease.
- To compare the number of apoptotic cells with the degree of neuronal loss in a mouse model of CJD.
Main Methods:
- Experimental infection of mice with the Fujisaki strain of CJD.
- Sequential sacrifice and brain tissue analysis at weekly intervals.
- Detection of apoptotic cells using in situ end labelling (TUNEL) and electron microscopy.
- Quantification of neuronal cell loss in selected brain regions.
Main Results:
- A low number of apoptotic cells (maximum 14 per brain) were detected, even in the terminal stages of the disease.
- Significant neuronal loss (mean 32%) was observed in terminally sick mice compared to controls.
- Neuronal loss varied by brain region, with the greatest loss in the septal nuclei (55%) and least in the hypothalamus (16%).
Conclusions:
- Despite extensive neuronal loss in experimental prion disease, apoptosis appears to play a minimal role.
- The findings suggest that non-apoptotic cell death pathways are predominantly responsible for neuronal demise in CJD.
- Further research is needed to elucidate the precise mechanisms of neuronal death in prion diseases.
