Aging affects morphology but not stimulated secretion of saliva in rats

Abstract

Background: The role of aging on the salivary gland function still remains
controversial and inconclusive. This study was undertaken to determine
the effects of aging on the morphology and secretion of salivary glands
using male Wistar rats.
Method: There were three age groups; group A (3 months old; n = 8), group B (6 months old; n = 8), and group C (9 months old; n = 8). Body weights, salivary gland weights, salivary flow rates, pH and salivary levels of sodium, potassium, calcium, chloride, bicarbonate, phosphate and total protein were measured and compared. Hematoxylin-eosin stained histological slides of the salivary glands were assessed for morphological changes.
Results: Body weights increased with age while mean parotid gland weight
was significantly higher in group B than in groups A and C. Mean salivary flow rate was significantly higher in group B and C than in group A, and
mean salivary pH was significantly higher in group B and C than group A.
Analysis of salivary electrolytes and total protein showed that mean levels
of sodium, potassium and bicarbonate increased with age significantly while
mean levels of calcium, chloride, phosphate and total protein did not show
significant change among the groups.
Conclusion: These findings showed that varying changes were observed in
the morphology of salivary glands of aging rats without impaired function.

Keywords: Aging, Salivary Glands, Salivary flow rates, Salivary electrolytes, Salivary total protein