The Development <i>in vitro</i> and <i>in vivo</i> of Fusion of the Palatal Processes of Rat Embryos

Abstract

ABSTRACT The feasibility of employing organ culture and transplantation techniques for obtaining fusion of the lateral palatal processes of the rat embryo was investigated. The methods of obtaining live embryos and the operations upon these embryos to obtain palatal tissues were described. Nineteen organ cultures of the unfused palatal tissues of 15-day Sprague-Dawley rat embryos were made. Five of these palates achieved fusion. Twenty transplantations of the unfused palatal tissues of 15-day Sprague-Dawley rat embryos were carried out. Ten of the heterografted palates developed fusion. Four of the five homografts achieved fusion. The morphology of palatal process closure was observed and photographed at regular intervals in the in vitro and in vivo experiments. The morphology of closure of the secondary palate as found in the experimental tissues differs slightly from that of normal Sprague-Dawley embryos. The tongue appears to have a direct relationship with morphology and mode of closure. Removal of the tongue from between the lateral palatal processes of the experimental tissues immediately modifies process morphology and mode of closure. The abnormal environments of both explants and transplants cause cellular ‘regressions, in them. The histological progress of cellular fusion appears similar for the experimental and normal tissues.