THE AMELIORATIVE EFFECTS OF HEPARIN AND DEPOLYMERIZED HYALURONATE ON DECOMPRESSION SICKNESS IN RATS

Abstract

The protective effects in decompression sickness of heparin, partially depolymerized hyaluronate (PDHA, a substance reported to have antilipaemic properties), and bishydroxycoumarin have been studied by a standardized compression–decompression technique in rats. Bishydroxycoumarin did not afford any significant degree of protection even at dose levels which prolonged the prothrombin time as much as five times normal. Heparin, however, significantly reduced the incidence of "bends" in rats at a dose which only briefly prolonged the whole-blood clotting time, and significantly reduced both the incidence and the severity at higher dose levels. PDHA produced the most marked reduction in both incidence and severity at dose levels which did not significantly alter the whole-blood clotting time. These protective effects were absent when heavy, fat rats were used, and when the compounds were administered before the compression (i.e. more than 2 hours before the actual evaluation of signs of the bends). In view of these results it is postulated that anticoagulation per se has little beneficial effect in treating the bends; the protection afforded by these mucopolysaccharides may be related to their lipaemia-clearing activity.