PHYSIOLOGICAL-STUDIES OF TURKEY TIBIAL DYSCHONDROPLASIA

Comparative differences between tibial dyschondroplastic (TD) and age- matched control turkey epiphyseal cartilages were studied using cellul ar, metabolic, and extracellular matrix characteristics. Alkaline phos phatase and aryl sulfatase activities were measured as variables of ca lcification and cartilage degradation, respectively. There was a decre ase in the activities of both enzymes in TD tissues. An increase in ti ssue phosphate concentrations was noted in the TD tissue whereas neith er tissue calcium nor serum calcium and phosphorus concentrations were affected. Profiles of noncollagenous and collagenous proteins from no rmal and TD-affected tissues were compared following in vitro biotinyl ation of epiphyseal cartilage followed by a sequential extraction usin g 4 M guanidine HCI and pepsin digestion, respectively. Electrophoreti cally separated proteins from both extracts were analyzed on Western b lots and compared for any prominent differences between normal and TD cartilages. Biotinylation enhanced the detectibility of extracted prot eins. There were, however, no major differences in the patterns of non collagenous or collagenous proteins between the two groups of tissues. Tibial dyschondroplastic lesions further exhibited a large number of dead chondrocytes, which increased with severity of lesion. There appe ars to be no significant difference in the pattern of extracellular-ma trix-associated proteins. However, enzyme and metabolic activities of TD-affected cartilages were significantly reduced, and this may be due to premature death of chondrocytes in the process of development.