The metabolism of sulphated polysaccharides in limb atrophy in the rat

Abstract

Two groups of adult rats, 12 normal controls and 12 rats operated upon to produce atrophy of one hind limb, were injected with 1 [mu]c/g body weight of NA235SO4, and half of each group were killed at 24 hours and half at 8-10 days. Sulfate was recovered and counted, as BaSO4, from 3 fractions of costal cartilage and mixed limb tissues of these rats, i.e., the total bound sulfate, the polysaccharide sulfate prepared from papain extracts of the tissues, and the residual sulfate remaining in the tissues after extraction of the polysaccharide sulfate. In the normal rats the polysaccharide sulfate from costal cartilage showed a loss of activity with time corresponding to a rate of turnover of about 17 days. This is in agreement with the rate of turnover of chondroitin sulfate from costal cartilage of normal adult rats found by Bostrom. The polysaccharide sulfate of limb tissues of the normal rats showed a greater loss of activity with time than the cartilage polysaccharide. Total bound sulfate of both limb tissues and cartilage, however, showed similar losses, both being greater than that of cartilage polysaccharide. The residual sulfate fraction from both limb tissues and cartilage actually showed a gain in activity during the 8 days of the experiment in the normal rats. In the operated rats all 3 sulfate fractions showed greater losses of activity during the 10 days of the experiment than in the normal rats, in the cartilage polysaccharide fraction. The difference was particularly marked in the residual sulfate fractions which showed loss of activity, in contrast to the gain in activity in the normal rats. The operation appeared to result in an increased rate of metabolism of one or more polysaccharides in the tissues generally and in particular in the atrophying limbs.