Objective: To investigate whether 14-3-3 eta protein is detectable in synovial fluid and blood serum of high performance horses and to study whether any significant correlation between this and matrix metalloproteinase 1 and 3 in horse synovial fluid.
Design: Clinical study.
Animals: Eleven standard breed horses (seven high performances and four controls).
Procedures: Blood serum and fetlock synovial fluid of seven high performance and four control horses were subjected to western blot for detection of 14-3-3 eta, gama, matrix metalloproteinase 1 and 3 proteins. 
Results: High level of 14-3-3 eta protein was detected in synovial fluid of high performance horses compare to those of control (P<0.05). 14-3-3 gama protein was detectable in synovial fluid and significant differences was found between high performance and control horses (P<0.05). The level of matrix metalloproteinase 1 and 3 were significantly increased in samples of high performance horses relative to of that control (p<0.05). The results showed that 14-3-3 eta protein was significantly increased in serum samples of high performance horses relative to of that control (P<0.05).
Conclusions and Clinical Relevance: 14-3-3 eta isoform can be readily detected in synovial fluid and blood serum of high performance horses and presence of this protein has significant effect on the levels of matrix metalloproteinase 1 and 3 in synovial fluid.
As the high performance horses are always prone to joint diseases, this protein might be use as an early diagnostic tool in some joint inflammatory conditions.