Changes in mouse whole saliva soluble proteome induced by tannin-enriched diet

Fifty-seven protein spots were excised from control group gels, and 21 different proteins were identified. With tannin consumption, the expression levels of one α-amylase isoform and one unidentified protein increased, whereas acidic mammalian chitinase and Muc10 decreased. Additionally, two basic spots that stained pink with Coomassie Brilliant Blue R-250 were newly observed, suggesting that some induced PRPs may remain uncomplexed or form soluble complexes with tannins.This proteomic analysis provides evidence that other salivary proteins, in addition to tannin-precipitating proteins, are affected by tannin ingestion. Changes in the expression levels of the acidic mammalian chitinase precursor and in one of the 14 salivary α-amylase isoforms underscores the need to further investigate their role in tannin ingestion.Saliva is an important fluid that rapidly adjusts to changes in dietary conditions. Salivary glands are mainly under nervous system control, and the composition of salivary secretions is rapidly altered over a wide range in response to various stimuli. Saliva serves as a physiological buffer against variations between the external and internal milieus. Such variations may be reflected in different salivary protein profiles resulting from different dietary habits. It was proposed that saliva protein composition varies also considerably among species, reflecting diverse diets and modes of digestion [1]. Animals using identical feeding niches may present similarities in their salivary protein composition, whereas the presence of particular proteins may be specific for particular feeding niches. For example, salivary amylase levels correlate with starch levels in each animal species' diet [2]. Moreover, salivary protein composition is modulated by diet. One example is the induction of salivary cystatins in rats ingesting capsaicin-containing diets [3]. Studies in humans have demonstrated changes in the salivary proteome induced by different basic tastes [4]