Model calculations of oxygen supply to tissue slice preparations.

Excised tissue slice preparations are widely used in experimental medicine, pharmacology and physiology. Since slices are separated from the vascular system they have to be supplied with oxygen from the bath solution in which the slices are fixed. Otto Warburg (Biochem. Z., vol.142, p.317-33, 1923) designed a simple model of oxygen diffusion in such a tissue preparation. His model does not utilise some important parameters which may influence the oxygen distribution in the tissue: unstirred bathing, non-vital superficial layers of tissue slices, damage by the cutting procedure and the influence of volume fraction and tortuosity over the oxygen supply. A compartment model has been designed to test how these parameters affect the oxygen distribution in tissue slices. The calculations have shown that all parameters may considerably affect the oxygen supply to tissue slices. Therefore, they have to be considered in the analysis of oxygen distribution and consumption in tissue slice preparations.