Thesis (Ph.D.) - Cairo University - Faculty of Veterinary Medicine - Department of Biochemistry and Chemistry of Nutrition

Osteoarthritis (OA) is one of the most degenerative joint diseases in both human and veterinary medicine. The objective of the present study is the early diagnosis of OA in donkeys using a reliable grading of the disease based on clinical, chemical and molecular alterations. OA was induced by intra-articular injection of 25 mg monoiodoacetate (MIA) as a single dose into the left radiocarpal joint of nine donkeys. Animals were clinically evaluated for 7months.Blood , synovial fluid and cartilage samples were collected for assessment of total GAGs and chondroitin sulphate (CS) concentrations, matrix metalloproteinases (MMPs) activity, expression level of COL2A1 protein, miRNA-146b, miRNA-27b,TRAF-6 and COL10A1 genes,histopathological and immunohistochemical analysis of Caspase-3. Animals showed the highest lameness score one week post-induction with the progression of radiographical and ultrasonographic changes. Total GAGs and CS levels were gradually increased in both sera and synovia.MMPs activity , COL2A1 and Caspase- 3 expression increased accompanied by articular cartilage degeneration and loss of proteoglycan.The level of expression of miRNA-146b,and 27b showed upregulation at early stages of OA followed by down regulation in late ones in both sera and synovia together with decreased expression in TRAF-6 gene. OA was successfully graded in Egyptian donkeys with the use of COL2A1 and Caspase-3 for prognosis. miRNA-146b, miRNA-27b and COL10A1 in sera provide promising noninvasive circulating biomarkers that discriminate between normal, early and late grades of OA. However, MMPs failed to differentiate between early and late OA

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