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Apoptosis in bone marrow cells of mice with different p53 genotypes after gamma-rays irradiation in vitro

Y F Cui1, P K Zhou, L B Woolford

  • 1Institute of Radiation Medicine, Beijing, P.R. China.

Journal of Environmental Pathology, Toxicology and Oncology : Official Organ of the International Society for Environmental Toxicology and Cancer
|January 1, 1995
PubMed

Insights

The p53 tumor suppressor gene influences apoptosis in bone marrow cells following radiation exposure. Mice lacking the p53 gene exhibit resistance to radiation-induced apoptosis, indicating a p53-independent pathway.

Area of Science:

  • Cell Biology
  • Genetics
  • Radiation Biology

Background:

  • Apoptosis, or programmed cell death, is crucial for development and tissue homeostasis.
  • The oncosuppressor p53 gene plays a recognized role in initiating apoptosis.
  • Radiation exposure can trigger apoptosis in various cell types, including bone marrow cells.

Purpose of the Study:

  • To investigate the role of the p53 gene status in radiation-induced apoptosis of murine bone marrow cells.
  • To compare apoptosis induction in bone marrow cells with different p53 gene genotypes (p53 -/-, p53 +/-, p53 +/+).
  • To explore the existence of p53-independent apoptotic mechanisms in response to irradiation.

Main Methods:

  • Utilized p53 gene-targeting mice (homozygous null, heterozygous, and wild type).
  • Exposed murine bone marrow cells to gamma-ray irradiation (6 Gy).
  • Quantified apoptotic cells and analyzed DNA laddering at 4 hours post-irradiation.

Main Results:

  • Homozygous null (p53 -/-) murine bone marrow cells showed increased resistance to radiation-induced apoptosis compared to p53 +/- and p53 +/+ genotypes.
  • The percentage of apoptotic cells in wild-type (p53 +/+) mice was approximately three times higher than in p53 -/- mice.
  • DNA ladder analysis confirmed reduced apoptosis in p53 -/- mice, yet apoptosis was still observed, suggesting an alternative pathway.

Conclusions:

  • Both p53-dependent and p53-independent apoptotic pathways are activated in murine bone marrow cells following gamma-ray irradiation.
  • The absence of the p53 gene confers resistance to radiation-induced apoptosis in bone marrow cells.
  • Previous findings of increased hemopoietic progenitor cell survival in p53-deleted mice are linked to apoptosis inhibition.

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