Movement of albumin between plasma and tissues after limb ischaemia in the rat

During the first few hours after limb ischaemia in the rat, the plasma protein concentration does not fall despite substantial compensatory fluid movement into the circulation. We have therefore attempted to find out whether this fluid is accompanied by albumin. Rats injected the previous day with 125I-labelled albumin were subjected to 4-h bilateral hind-limb ischaemia. The uptake of label by the hind limbs and the changes in plasma albumin and 125I concentrations were measured during the subsequent 3 h. The calculated concentration of albumin in the fluid moving into the injured tissues was similar to the measured concentration in the oedema fluid and about half the plasma albumin concentration, which fell slightly. The accumulation of albumin in the injured legs almost balanced the loss from the circulation and there was little or no mobilisation of albumin from uninjured tissues. The data were consistent with early compensation largely by transcapillary refilling.