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p53-deficient mice are protected against adrenalectomy-induced apoptosis
1Department of Neurology, USC School of Medicine, Los Angeles 90033, USA.
Abstract:
The p53 tumor suppressor gene, an important regulator of the cell cycle, has been implicated in apoptotic cell death in vitro, and more recently in neuronal degeneration in vivo. The present study investigated the importance of p53 expression in the apoptotic death of hippocampal granule cells following adrenalectomy. Mice, either homozygous or heterozygous for the p53 null allele and wild-type controls were sacrificed 16 days after adrenalectomy. Hippocampal morphology was assessed in paraffin sections stained with hematoxylin and eosin. Cells exhibiting features characteristic of apoptosis were evident in hippocampi from wild-type mice. A significant decrease in the number of apoptotic cells was observed in both homozygous and heterozygous mice. These findings demonstrate that absence or attenuation of p53 expression protects granule cells from adrenalectomy-induced apoptosis and, combined with the results of other studies, suggest that p53 is required for certain types of neuronal degeneration.
Insights
The p53 tumor suppressor gene is crucial for programmed cell death in neurons. Its absence or reduction protects hippocampal cells from degeneration after adrenalectomy, indicating p53
Area of Science:
- Neuroscience
- Molecular Biology
- Genetics
Background:
- The p53 tumor suppressor gene regulates the cell cycle and is involved in apoptosis.
- p53 has been linked to neuronal degeneration in vivo.
- Hippocampal granule cells are vulnerable to cell death following adrenalectomy.
Purpose of the Study:
- To investigate the role of p53 gene expression in the apoptotic death of hippocampal granule cells after adrenalectomy.
- To determine if p53 deficiency affects neuronal degeneration in the hippocampus.
Main Methods:
- Adrenalectomy was performed on mice.
- Mice with homozygous or heterozygous p53 null alleles and wild-type controls were used.
- Hippocampal morphology was assessed using hematoxylin and eosin staining 16 days post-adrenalectomy.
- Apoptotic cells were quantified.
Main Results:
- Apoptotic cells were observed in the hippocampi of wild-type mice after adrenalectomy.
- A significant reduction in apoptotic cells was found in both homozygous and heterozygous p53 null mice.
- Absence or reduced p53 expression protected hippocampal granule cells from adrenalectomy-induced apoptosis.
Conclusions:
- p53 expression is required for adrenalectomy-induced apoptosis of hippocampal granule cells.
- The absence or attenuation of p53 protects these neurons from degeneration.
- These findings suggest p53 plays a necessary role in specific types of neuronal degeneration.