The Effect of lschaemia on Acid Phosphatase, B-Glucuronidase and Lactic Acid Dehydrogenase in Lymph from Hind Paw of the Rabbit

Abstract

The effect of ischaemia of the hind paw of the rabbit on the release of the lysosomal enzymes,
acid-phosphatase and ~-glucuronidase, and of lactic acid dehydrogenase (LDH) was assessed by
measuring the activities of these enzymes in the lymph from the paw before and at varying
intervals after the release of a tourniquet applied for 4 hr just above the ankle.
Histologically, this degree of ischaemia produced considerable necrosis of the plantar muscles
with ultimate regeneration within 4 weeks.
The levels of activity of the lysosomal enzymes in lymph from the normal paw were less than
those in plasma. The mean lymph:plasma ratios were 0.38 for total protein, 0.28 for acid-phosphatase
and 0.08 for ~-glucuronidase, suggesting that these enzymes in the lymph were derived
mainly from the plasma with a degree of molecular sieving at the blood capillary wall.
Ischaemia increased the permeability of the capillaries to all these macromolecules, but there was
no evidence of any appreciable release of lysosomal enzymes from the injured cells or from the
invading phagocytic cells.
During the period of muscle degeneration from l to 7 days after release of the tourniquet, the
level of activity of ~-glucuronidase was significantly less in lymph from the affected paw than in
lymph from the normal paw. It seems likely that in the areas of muscle necrosis the enzyme in
the tissue fluid originating from the blood plasma was involved in the lytic processes of the
damaged muscle cells.