Sulfated glycosaminoglycans in rat lung tissue during experimental silicotic fibrosis

The biosynthesis of sulfated glycosaminoglycans (GAG) was studied in healthy and fibrotic lung tissue (experimental silicosis). Male rats received a single intratracheal instillation of 25 mg quartz dust (DQ 12) in 0.7 ml saline and were sacrificed at days 15, 30, 90, 150 and 240 after the insult. GAGs were labeled in vivo by i.p. (intraperitoneal) administration of [35S] sulfate. The concentration of GAGs in delipidated dry tissue was unaffected, however, the uptake of [35S] sulfate into silicotic lung tissue was significantly higher than in controls. Identification of sulfated GAGs isolated from pooled samples by DEAE-cellulose chromatography was achieved by electrophoresis and chondroitinase digestion. The most marked change in the label distribution among individual GAGs occurred with regard to dermatan sulfate. The fraction of label in dermatan sulfate was elevated in silicotic lung.