Long-term administration of whey alters atrophy, gene expression profiles and dysfunction of salivary glands in elderly rats

• Whey-drinking prevented and/or restored age-dependent atrophy of the sublingual glands (SLGs) in elderly rats.
• Whey-drinking up-regulated the genes associated with salivary proteins and tissue repair.
• Whey-drinking down-regulated the genes associated with lipid metabolism and senescence.
• Venn diagram analysis revealed that Tcfap2b and Abpa played important roles in whey-induced gene profiles.
• Whey recovered age-dependent functional decline of the SLGs in relation to gene expression.

Salivary glands in elderly individuals commonly exhibit morphological changes and dysfunction resulting in xerostomia. Long-term (4-week) drinking of whey prevented and/or restored age-dependent decline of salivary volume and protein concentration, and atrophy of sublingual glands (SLGs) significantly in 88-week-old rats. The transcripts of 42 genes were up-regulated and 7 genes were down-regulated by more than 1.5-fold change with FDR ≤0.1 after whey-drinking. The expression levels of genes associated with salivary proteins and tissue repair were significantly increased, while those associated with lipid metabolism were decreased. Venn diagram analysis revealed that expressions of 13 genes, including Tcfap2b and Abpa, were induced significantly by whey-drinking. Furthermore, secretory protein levels in SLGs and saliva were revealed by immunoblot analysis. This is the first study to report that whey-administration can prevent and/or restore age-dependent atrophy and functional decline of SLGs in relation to gene expression and thus may serve as a functional food ingredient.