LYMPHATIC HYALURONAN FLUX FROM SKIN INCREASES DURING INCREASED LYMPH-FLOW INDUCED BY INTRAVENOUS SALINE LOADING

Hyaluronan is a structural component of the interstitial matrix in ski n and is catabolized locally in skin as well as by lymphatic removal a nd subsequent degradation in lymph nodes and liver. The present experi ments were designed to evaluate the role of interstitial fluid flux in turnover of hyaluronan in skin by measuring the maximal lymphatic flu x of hyaluronan. Lymph flow, total protein concentration, hyaluronan c oncentration, and flux were measured every 15 min in prenodal lymph fr om the hind paw in 12 pentobarbital-anesthetized mongrel dogs at norma l and increased interstitial fluid flux. An intravenous saline load (1 5% of body weight during the course of 30 min) was followed by a one-s tep increase in local venous pressure 30 min later (to a maximum of 50 mm Hg) and maintained at this level for the next 240 min. Lymph flow and hyaluronan concentration during the control period averaged 25.6 /- (SD) 23.2 (range 4.7-61.9) mu l/min and 8.6 +/- 2.8 (range 2.0-11.6 ) mu g/ml, respectively. The hyaluronan concentration fell by 30% duri ng the experimental period, while the lymph flow increased up to ten t imes above control. Total tissue water increased from 1.73 +/- 0.11 ml /g dry weight during the control period to 1.91 +/- 0.12. ml/g dry wei ght at the end of the experiment (p < 0.01). The corresponding tissue contents of hyaluronan averaged 3.5 +/- 0.9 and 3.6 +/- 0.6 mg/g dry w eight, respectively (p > 0.05). The average lymphatic hyaluronan flux was 8.4 +/- 5.4 mu g/h during the control period, peaked at about 60 m u g/h, and averaged 33.6 +/- 13.9 mu g/h during the last hour of the e xperimental period. The total amount of hyaluronan drained from the pa w during the 5-hour experimental period averaged 182 +/- 137 (range 39 -525) mu g and corresponds to the normal daily lymphatic output of hya luronan. Thus, the hyaluronan flux in lymph increases with increasing lymph flow and is maintained over a period of several hours, affecting hyaluronan turnover in skin.