|Lay, jr, Jackson|
Submitted to: Avian Diseases
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/5/2010
Publication Date: 12/1/2010
Citation: Rasaputra, K., Liyanage, R., Lay, Jr, J., McCarthy, F., Rath, N.C. 2010. Tibial dyschondroplasia associated proteomic changes in chicken growth plate cartilage. Avian Diseases. 54(4):1166-1171. Interpretive Summary: Tibial dyschondroplasia (TD) is a leg problem in meat-type poultry that affects the knee joint, causing lameness. We compared the protein differences in the healthy and diseased joint tissues by a process called electrophoresis to find the cause of the disease. We found that some of the proteins associated with survival of the cartilage cells were reduced suggesting that the loss of vital processes may be responsible for the development of the disease.
Technical Abstract: Tibial dyschondroplasia (TD) is a poultry leg problem that affects the proximal growth plate of tibia preventing its transition to bone. To understand the disease-induced proteomic changes we compared the protein extracts of cartilage from normal and TD- affected growth plates. TD was induced by feeding thiram to chickens two weeks prior to the tissue harvest. Proteins were extracted from whole tissues and conditioned media (CM) prepared by incubating appropriate growth plate tissues in serum-free culture media for 48 hrs. The extracts were prefractionated to contain proteins ranging between 10 and 100 kDa. Equal amounts of proteins were subjected to 2D gel electrophoresis using three individual samples per group. The gels were silver stained and the digital images were compared and analyzed using Melanie software to determine differentially expressed protein spots. On comparison between two sets of gels, 47 matching spots were detected in tissue extracts and 27 in CM extracts. Among the matching spots, 12 were determined to be down regulated in tissue extracts (p<0.05) and 2 in CM extracts (p<0.05) of TD-affected growth plates. Altogether, 32 protein spots could be identified in both tissue and CM extracts by in-gel trypsin digestion, followed by peptide mass finger printing and MS/MS fragmentation. Some of the down-regulated proteins included alpha-enolase, G protein, origin recognition complex, peptidly prolyl isomerase, calumenin, type II collagen precursor, and the EST pgm2n.pk014.f20, a protein with homology to human reticulocalbin-3 (RCN3). Most of the down regulated proteins are associated with tissue signal transduction, energy metabolism, and secretory functions that are integral to cell viability. Consistent with our earlier findings that the TD chondrocytes are non-viable, the current results suggest that the thiram very likely interferes with basic metabolic functions of chondrocytes, leading to their death consequently to the pathogenesis of TD.