INFLUENCE OF OXYGEN ON VIABILITY AND PROLIFERATION IN CELLULAR SPHEROIDS

The local variation in oxygen tension in human glioma and hamster V-79 spheroids was measured using double barrel platinum microelectrodes. Minimum oxygen tensions in the central regions were found in spheroids having diameters of about 600-800 and 300-400 μ m for the human and the hamster spheroids, respectively. These dimensions closely corresponded to the diameters at which the first central necrotic processes could be observed. However, the oxygen tension in the central regions thereafter continuously increased during the growth of the spheroids and the enlargement of the central necrotic regions. Cultivation in oxygen atmosphere only slightly increased the thickness of the viable layers in the hamster V-79 spheroids while no significant changes could be measured in the human glioma spheroids. The results indicate that the degenerative changes in the center of spheroids does not only result from deficiency of oxygen. Furthermore, it seemed like processes in the necrotic debris forced more and more of the viable cells to necrosis. Culture in nitrogen atmosphere decreased the thickness of the viable layers and inhibited proliferation in both types of spheroids. © 1979.