SOME HISTOLOGICAL AND HISTOCHEMICAL ASPECTS OF EGG-IMPLANTATION IN THE RAT

The rat embrayo and uterine epithelium were studied during implantation at 129h p.c., 138h p.c. and 153h p.c., stages. The basophilic bodies found in the inn£>r cell mass and in the uterine epithelium represent dead cells with a dense stained cytoplasm and pyknotic nuclei. However, these bodies found in the trophoblast cells represent phagocytosed dead or degenerated epithelial cells that expelled from the uterine epithelium toward the blastocyst. All these bodies are strongly stained for protienss, DNA, and polysaccharides. A variable content of protiens, RNA, and DNA was reported in the trophoblast and inner cellular mass as well as in all layers of the embrayo during the implantation stages. However, an increase in polysaccharides was observed during lare stage (1S3h p.c.) in ther rat egg-cylinder, suggesting that the embrayo consumes the polyccharides as an energy sourse material during the period of blastocyst implantation as well as during transformation into the egg-cylinder. Cells of the uterine epitlu.•lium showed Cl'rtain features of dl'gi'IJI'ration sueh as vacoulation, shrinkage and pyknotic nuclei. Also, a decrease in the protien, RNA, and polyccharide contents of the uterine epithelium was observed. These changes take place during the whole break down of the uterine epithelium which occured at the late period of implantation (153h p.c., stage).