Modulation of branching morphogenesis of fetal mouse submandibular gland by sodium ascorbate and epigallocatechin gallate.

As an initial step to study the effect of antioxidants on the oral environment, we here investigated how sodium ascorbate and (-)-epigallocatechin 3-O-gallate (EGCG) affect the branching morphogenesis of the fetal mouse submandibular gland (SMG). When mouse SMG was prepared from the embryo at 13-day post prenatal stage and cultured, gradual development of branching morphogenesis was observed. Addition of sodium ascorbate affected this morphological change in a bimodal fashion. At lower concentrations of sodium ascorbate (0.25 approximately 2.27 mM), the branching morphogenesis was slightly but significantly (about 60%) enhanced, whereas at higher concentrations of sodium ascorbate (6.82 approximately 10.1 mM), the branching morphogenesis was inhibited. The addition of EGCG failed to stimulate, but inhibited the branching morphogenesis in a dose-dependent manner. These data support that the addition of a lower concentration of sodium ascorbate is essential to stimulate the growth of SMG, and that sodium ascorbate, but not all antioxidants, induces hormesis (beneficial action at lower concentration) in the present SMG system.