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Age-related changes in proliferating cell nuclear antigen levels
M Tanno1, M Ogihara, T Taguchi
1Department of Nuclear Medicine and Radiological Sciences, Tokyo Metropolitan Geriatric Hospital, Japan.
Mechanisms of Ageing and Development
|November 29, 1996
Summary
Aging significantly impairs liver regeneration in rats by reducing proliferating cell nuclear antigen (PCNA) levels and cellular proliferation. Aged rats show diminished PCNA, hindering their liver
Area of Science:
- Cell Biology
- Gerontology
- Hepatology
Background:
- Aging is associated with a decline in organ regeneration capacity.
- Proliferating cell nuclear antigen (PCNA) is a crucial marker for cellular proliferation.
- Understanding age-related changes in liver regeneration is vital for regenerative medicine.
Purpose of the Study:
- To investigate the impact of aging on rat liver regeneration.
- To compare proliferating cell nuclear antigen (PCNA) levels in young and aged rats during liver regeneration.
- To elucidate the role of different PCNA forms in age-dependent regenerative capacity.
Main Methods:
- Partial hepatectomy was performed on young (2-month-old) and aged (24-month-old) rats.
- Liver tissues were collected 48 hours post-surgery.
- PCNA levels and forms (P, L, H types) in nucleoplasm and cytoplasm were analyzed using phosphocellulose column chromatography and immunostaining.
- DNase treatment was used to characterize PCNA forms.
Main Results:
- Young rats showed significant increases in cytoplasmic L-type and nucleoplasmic H-type PCNA during regeneration.
- Aged rats exhibited decreased basal levels of PCNA and a lack of significant increase during liver regeneration.
- The H-type PCNA was identified as a complex of PCNA and DNA, with L-type representing newly synthesized PCNA.
Conclusions:
- The reduced levels and impaired increase of PCNA in aged rats correlate with a decreased rate of cellular proliferation during liver regeneration.
- PCNA's role in DNA binding and cellular proliferation is fundamental for liver regeneration in young rats.
- Aging significantly compromises the molecular mechanisms underlying liver regeneration, primarily due to diminished PCNA availability and function.
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