To investigate age-related changes in proliferative markers in palatal salivary glands and to discuss the potential role of the age-related increase in the inflammatory infiltrate in these changes.
Material and methods:
Twenty-four post-mortem samples were equally divided into young (12-21 yr), adult (32-45 yr), and old (72-97 yr) age groups. Thirty acinar and ductal nuclei from each sample were assessed for the number and area of AgNORs (nNOR and TVNOR, respectively). PCNA-, Ki-67- and p53-stained nuclei were recorded in 10 high power fields and expressed as a percentage from the total number of nuclei of each cell type. One-way ANOVA and Kruskal-Wallis one-way ANOVA statistical tests were used.
Among AgNOR parameters, only nNOR of the acini decreased significantly with age (p=0.013); all other results were not statistically significant. A 3- and 7-fold increase in mean percent of PCNA acinar and ductal cells was found with age (p=0.041 and p=0.0095, respectively). Neither acinar nor ductal Ki-67 positive nuclei were found. Nuclear p53 staining was absent.
In the acinar cells, the pattern of changes of the examined markers infers an increase in their metabolic synthetic activity with age. In the ductal cells, the pattern of changes indicates that they are under a strong cellular defence stress response to a high load of DNA damage. It is suggested that the damage was induced by the adjacent inflammatory infiltrate and its associated products, which accumulate with aging in these glands.
palatal salivary glands, aging, inflammatory infiltrate, DNA damage, neoplasm