The response of rat submandibular salivary gland to plant protein diet; Biological and histochemical study

Objective: This investigation aimed at studying the effect of plant protein diets on the salivary glands. It compares 3 protein’s types on the submandibular gland structure and function. The submandibular gland was chosen because it contains all the elements of the salivary glands. The different protein types were chosen to answer if the plant protein or legume plant protein can be replaced for the animal proteins.Methods: Thirty young albino rats were divided into 3 dietary groups: group I was fed 10% skim milk and acts as a control, group II was fed corn that is a cereal plant protein, while group III was fed 10% soybean, which is a legume plant protein. The animals were sacrificed after 2 months from the beginning of the experiment and the submandibular salivary glands were prepared for the biochemical analysis and histological, as well as, histochemical studies.Results: The biochemical analysis revealed that total protein in soybean fed group was nearly the same as that of the control, while being significantly decreased in the corn fed group. The histological appearance of the submandibular salivary gland of both study groups showed shrinkage in the acini and ducts. The histochemical results showed an intense preci­pitation for total protein in the soybean group, while the corn fed group showed a mild precipitation. The reaction for DNA and RNA was intense in the control group as compared with both study groups.Conclusion: From this study, it was apparent that the plant protein had adverse effects on the submandibular salivary gland and impairs its function. Thus, plant protein including the soybean cannot replace animal protein which is ideal for the normal growth and function of the gland.