Date on Master's Thesis/Doctoral Dissertation

5-2015

Document Type

Master's Thesis

Degree Name

M.S.

Department

Oral Biology

Degree Program

Oral Biology, MS

Committee Chair

Sandell, Lisa

Committee Co-Chair (if applicable)

Darling, Douglas S.

Committee Member

Shumway, Brian S.

Committee Member

Warner, Dennis

Subject

Vitamin A in human nutrition; Salivary glands--Growth

Abstract

Submandibular salivary glands (SMG) are important for the production of saliva. Salivary glands may be damaged by autoimmune disease, surgery, or radiation therapy. Retinoic acid (RA) is a signaling metabolite derived from Vitamin A that is essential for proper embryonic growth and development; specifically for cardiovascular, limb and craniofacial development. The goal of this study was to determine if there is a reproducible defect in the growth of SMGs in RA deficient mouse embryos compared to wild type. This study aims to characterize SMG growth in RA deficient embryos and determine if the growth could be stimulated by RA in a dose dependent manner. In addition, we hypothesized that there was a direct effect of the RA deficiency on SMG growth using an in vitro model. We examined Rdh10 mutant mouse embryos: which lack the enzyme retinol dehydrogenase necessary to produce RA. We examined the SMGs of wild type and Rdh10 mutant embryos by hematoxylin and eosin staining at various stages of gland development. We then completed whole mount antibody staining for the epithelium (E-cadherin) and nerve (TUJ), and compared the volumes of these glands. We also varied the dosage of all-trans-retinal (RAL), the intermediate in RA metabolism, supplementation to determine how this affects SMG growth. The mutant SMGs were approximately half the size of the wild type SMGs at both the early stage of gland development and further into development. With the higher dose of RAL, the mutant SMGs appeared more like the wild type, with branching and near normal SMG size. In order to see if RA directly affected SMG growth, wild type SMGs were cultured in vitro for up to 72 hours. SMGs treated with a synthetic Retinoic acid receptor (RAR) inhibitor (BMS 493) had less epithelium and branching compared to the control SMGs. Together, the results of these analyses demonstrate that RA directly affects SMG growth: specifically the epithelial growth and differentiation are influenced by the presence and dosage of RA.

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