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Rheological evaluation of the mechanical properties of equine synovial fluid from tarsocrural joints injected with hy

Rheological evaluation of the mechanical properties of equine synovial fluid from tarsocrural joints injected with hyaluronic acid (HA). Heidi Schmidt Advisors: Dr. Skip Rochefort PhD and *Dr. Jill Parker VMD DACVS Danielle Leiske, Jocelyn Frey, and *Autumn Rankin

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Rheological evaluation of the mechanical properties of equine synovial fluid from tarsocrural joints injected with hy

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  1. Rheological evaluation of the mechanical properties of equine synovial fluid from tarsocrural joints injected with hyaluronic acid (HA) Heidi Schmidt Advisors: Dr. Skip Rochefort PhD and *Dr. Jill Parker VMD DACVS Danielle Leiske, Jocelyn Frey, and *Autumn Rankin Dept. of Chemical Engineering and *College of Veterinary Medicine Oregon State University Corvallis, OR

  2. Outline • Motivation • Background • What is HA • Horse and synovial fluid overview • Information about HA supplementation via Hyvisc® • Experimental Design • Tests • Steady Shear Viscometry • Dynamic Oscillatory Shear Rheometry • Capillary Viscometry • Results

  3. Motivation • Lameness: Limping, abnormal gait, or hobbling resulting from partial loss of function in a leg • Osteoarthritis is a significant cause of equine lameness, resulting in the deterioration of joint cartilage and formation of painful bone spurs • Economic Impact: Approximately $1 billion a year in losses due to lameness

  4. Background SynovialFluid • Viscous liquid present in all articular joints • Properties • Viscosity relates to joint lubrication • Elasticity relates to impact resistance (i.e. “shock absorbance”) • HA (hyaluronic acid) is the major contributor to the viscoelastic properties of synovial fluid.

  5. Hyaluronic Acid (HA) • Biopolyelectrolyte from rooster combs, human umbilical cords, and bacterial fermentation processes • High molecular weight (0.2-2 million Da) • $450,000/lb (from Sigma Chemicals) • Exhibits viscoelastic properties

  6. Joint Supplementation • Intra-articular injection of HA is a common treatment for controlling symptoms of osteoarthritis. • Mechanisms are not well understood • Supplementation may stimulate increased production of endogenous high molecular weight HA • It may protect endogenous HA from enzymatic degradation in osteoarthritic joints

  7. Hyvisc® vs. Synovial Fluid Hyvisc® Synovial Fluid .

  8. Objective • Compare the mechanical properties of synovial fluid from horses treated with HA to synovial fluid from untreated horses. • Studies on normal, healthy joints

  9. Experimental Design • Five horses (10 healthy hocks) divided into three groups • Treatment Group (4 hock joints) • Received 2 mL (22 mg) HA supplementation (Hyvisc®) • Negative Control Group (3 hock joints) • Received no joint supplementation • Positive Control Group (3 hock joints) • Received 2 mL of sterile Lactated Ringers Solution (LRS)

  10. Experimental Design • Synovial fluid collections: • Treatment day (before injections) • 7 days post treatment • 14 days post treatment • The horses were monitored daily for any signs of disease • Cytology was performed on all of the synovial fluid samples to monitor the health of the joints during the study.

  11. Experimental Design • Test Measurements • Steady Shear Tests : Viscosity • Dilute Capillary Viscometer Tests : Relative Viscosity • Dynamic Oscillatory Shear Tests: Viscosity & Elasticity

  12. Rheometer Geometries Rheometrics Fluids Spectrometer II

  13. Shear stress Shear rate Steady Shear Tests • Bottom plate rotates at a constant speed (shear rate) • Torque measured on upper cone (shear stress) Newtonian Plateau Shear Thinning (Non-Newtonian)

  14. Data Analysis Data Analysis

  15. Dynamic Oscillatory Shear Tests • Cone oscillates • Measures strain, stress • G’: Elastic Modulus • G”: Viscous Modulus • G’<G”: Viscous • Acts as a lubricant • G’>G”: Elastic • Behaves like a shock absorber Hyvisc® G’ G’’ G’’ G’ Cross-over Point

  16. HA Treated Horse Dynamic Oscillatory Shear Test Data Analysis

  17. Dilute Solution Capillary Viscometer • Measures relative viscosity in dilute polymer solutions • Flow times differ because of variations in concentration and molecular weight of HA Timing Lines Capillary Solution flow time Relative Viscosity = Solvent flow time

  18. HA Treated Horse Relative Viscosity Comparison

  19. Average Relative Viscosity Values at 0.5 Concentration

  20. Average Viscosity at g =0.1

  21. Percent Change of Synovial Fluid Properties 1 Week Post-Treatment . .

  22. Percent Change of Synovial Fluid Properties 2 Weeks Post-Treatment . . G' G'' Viscosity at γ= 0.1 Viscosity at γ= 10 Relative viscosity

  23. Conclusion Hyaluronic Acid supplementation has a positive affect on the rheological properties of synovial fluid one week post-treatment

  24. Future Work • Extend research to a larger test group • Study the effects of intravenous HA injections • Perform light scattering tests to find specific HAconcentration and molecular weight • Explore the effects of HA supplements at different molecular weights

  25. Acknowledgements • Howard Hughes Medical Institute • Dr. Skip Rochefort, OSU ChE Dept • Danielle Leiske and Jocelyn Frey • Dr. Jill Parker and Autumn Rankin, OSU College of Veterinary Medicine • Kevin Ahern

  26. Questions? Danielle Leiske and Autumn Rankin Preparing the joint for an injection

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