Abstract
Histopathological studies of experimental vitamin B_<12> deficiency using rats have been performed. In peripheral blood, marked leucopenia and macrocytic anemia accompanied by anisocytosis were observed, though no megaloblast was encountered. In heart, moderate atrophic and degenerative changes of muscle fibers were found, and small necrotic foci were demonstrated in severe cases. In stomach, marked atrophy of mucosa were observed. Glandular cells revealed enlargement of cell bodies, exhibiting marked vacuolar degeneration. Desquamation of lining epithelia was encountered. Bowels exhibited catarrhal changes of mucosa. Marked atrophy and degenerative changes of liver cells were encountered. Centrolobular liver cells showed marked decrease of RNA granules, whereas liver cells of peripheral portions exhibited marked increase of RNA granules of cytoplasm. In bone marrow, degenerative changes and decrease of number of nuclei of megakaryocytes, decrease in number of matured erythrocyte and leucocyte were noticed, though a large number of enlarged erythroblasts were found. In brain, especially spinal cord and spinal ganglion, marked atrophic changes of nerve cells were demonstrated. No marked degenerative change was encountered in peripheral nerve fibers except for degeneration of myeline sheath in preterminal region. Testes revealed atrophic changes and arrest of spermatogenesis.
