The oxygen release from human erythrocytes flowing in oxygen-permeable fluorinated ethylenepropylene copolymer narrow tube (25μm in inner diameter) was examined under various centrifugal forces applied perpendicularly to their flow direction. The flow dynamics of the cells was observed under a microscope using an apparatus constructed on a new centrifuge system (the maximum force, 10.6 G), and was evaluated by the marginal cell-free layer and/or the cell flow column, as described elsewhere. In addition, the images obtained through five interference filters with different wavelengths were used for the determination of the oxygen saturation of the cells with an image analyzer.
Exposing the narrow tube to zero oxygen tension, erythrocytes were deoxygenated in proportion to their traveling distance. The oxygen release was enhanced with decreasing the cell flow velocity and the hematocrit. With increasing the centrifugal force, the oxygen release from cells was suppressed accompanying the reduction of the cell flow column and the shift of the column to centrifugal side. The suppression of oxygen release was more evident in lower hematocrit. The phenomena qualitatively agreed with the inhibition of oxygen release resulting from the expansion of cell-free layer induced by erythrocyte aggregation with Dextran T-70 (MW=70400). This study suggests that the centrifugal force affects the oxygen transfer from erythrocytes to tissues through the changes of flow dynamics of the cells.

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