A STUDY OF THE CHEMICAL-COMPOSITION OF THE PROXIMAL TIBIAL ARTICULAR-CARTILAGE AND GROWTH-PLATE OF BROILER-CHICKENS

This study was undertaken to analyze the chemical composition of the p roximal tibial articular cartilage and growth plate from 1-mo-old broi ler chickens. The composition was different between the two types of c artilage (weight-bearing tissue and the tissue of growth center). The dry matter and collagen contents and the ratio of keratan sulfate to s ulfated glycosaminoglycan (GAG) were higher, and the total GAG uronic acid, chondroitin sulfate, hyaluronic acid, and sialic acid contents w ere lower in the articular cartilage than in the growth plate. Chondro itin sulfate was the major GAG, accounting for an average 96% of total GAG in both tissues. The size of chondroitin sulfate examined by gel chromatography was similar between the two tissues. The articular cart ilage contained a small amount of dermatan sulfate (approximately 1% o f total GAG) with low iduronic acid content (38% of total uronic acid) . There was no appreciable amount of dermatan sulfate found in the gro wth plate. Proteoglycans were extracted from these tissues with 4 M-gu anidine hydrochloride and separated by ion-exchange chromatography and gel chromatography. The uronic acid to protein ratio in the proteogly can fraction was similar (average 2.6) between the two tissues. Howeve r, gel electrophoresis of chondroitinase-ABC digests of proteoglycan f raction showed differences in their composition.