Ischemia-reperfusion does not cause significant hyaluronan depolymerization in skeletal muscle

The size of hyaluronan in lymph and gastrocnemius muscle was measured to test the hypothesis that reperfusion of ischemic skeletal muscle leads to hyaluronan depolymerization. Prenodal lymph was collected from the gastrocnemius muscle in anesthetized rabbits. Hyaluronan size was measured using a combination of agarose gel electrophoresis and a radiometric assay. In control legs, muscle contained primarily high-molecular-weight hyaluronan (greater then 4 x 10(6)), while lymph contained primarily low-molecular-weight hyaluronan (less than 0.79 x 10(6)) which was absent from tissue. Following 3 h of ischemia and 8 h of reperfusion, the lymph flux for high-molecular-weight hyaluronan was 25 times the value from the control leg. Neither the size nor the content of hyaluronan in tissue decreased. Muscle albumin content from the reperfused leg was 2.3 times the value from the control leg, while lymph albumin flux was 4 times the control value. Measurements following 24 h of reperfusion confirmed the absence of changes in the size or content of hyaluronan in tissue although an increased albumin content and wet weight-to-dry weight ratio indicated sustained edema. The daily removal of hyaluronan by lymph was calculated to be 2-3% of the tissue content. Since the lymph drainage of hyaluronan represented only a very small fraction of tissue hyaluronan, the amount of depolymerization was too small to produce significant changes in the tissue.