1Kassem M, 2Maklad S, 2Selim F, and 2EL-Sheikh N
1Histology Department, Faculty of Medicine (Assiut) and 2Microbiology Department Faculty of Medicine for Girls, Al-Azhar University.
It has been shown that apoptosis plays an important
role in a wide variety of physiological processes including aging. Advanced age
can be correlated with either reduced or enhanced apoptotic sensitivity,
depending apparently on the tissue selected or perhaps the species from which
it is obtained. This work attempted to investigate the impact of aging on
different tissue organs with different regenerative capacity such as intestine,
liver and heart and to identify the influence of antioxidant, vitamine C supplementation.
Cryo-sections of the above mentioned tissues were obtained from three age
groups of normal Balb C mice aged (1, 6, >12 months) before and after
vitamine C supplementation. DNA fragmentation of apoptotic cells was detected
by terminal deoxytranseferase (TdT)-mediated dUTP nick-end labeling (TUNEL)
assay. Although, apoptotic cells were found to be more frequent in the
intestinal tissue of all age groups yet they were more abundant in old age
(25%) compared with middle (21% and young age (18%) mice groups and at the tips
of the villi more than the basal compartment. In the liver the frequency of
apoptotic cells was (0.02%) and no difference was detected between the three
age groups. While, the cardiac tissue of all groups was negative for apoptosis.
No changes in the apoptotic pattern or number were revealed after vitamine C
supplementation except some reduction in apoptotic cells in the intestinal
tissue. In conclusion, aging has a positive impact on the function of different
organs especially those with rapid and continuous epithelial cell turnover such
as intestine. Absence of mitotic activity in the cardiac tissue makes it
completely negative for apoptosis. Thus, apoptosis may be important for
elimination of damage, dysfunctional cells that may threaten homeostasis and
regenerative capacity of the tissues.