ULTRASTRUCTURE OF IMPLANTED TROPHOBLAST CELLS OF YELLOW AGOUTI MOUSE

  • 1 January 1976
    • journal article
    • research article
    • Vol. 122  (SEP) , 177-188
Abstract
Ay/a female were injected with 5-10 IU of pregnant mare serum gonadotropin. Two days later they were injected with 5-10 IU of human chorionic gonadotropin. This hormonally induced superovulation was conducted to render more likely the accurate determination of developmental stage. From 100-105 h after mating, the animals were sacrificed, the uteri removed and the blastocysts fixed in glutaraldehyde, followed by osmium tetroxide, dehydrated in ethanol and embedded in Epon. Ultrathin sections were stained with uranyl acetate and lead citrate and examined by EM. Normal trophoblast cells revealed abundant free ribonucleoprotein particles, contorted nuclei with prominent nucleoli, junctional complexes, interdigitations with adjacent cells, a basal lamina facing the blastocoel, mitochondria with transversally and longitudinally oriented cristae, microfibrillar bundles, microtubules, lipid droplets and membrane-bound multivesicular bodies. The most conspicuous features of abnormal cells were empty areas in the cytoplasm and vacuolated mitochondria. The appearance of blastocysts in the light microscope is an invalid criterion for the determination of normality, because a normal blastocyst in the light microscope could reveal a predominance of abnormal cells in the EM.