title: Osmotic flows across the blood-joint barrier.
abstract: The effective osmotic pressure across the blood-joint barrier is a key factor controlling synovial fluid volume and joint effusions. The effect of plasma colloid osmotic pressure (COP) on trans-synovial flow was studied directly in rabbit knees expanded by intra-articular fluid infusion. The synovial microcirculation was perfused with blood of varying COP. Absorption of fluid from the joint cavity was a linear function of COP; but albumin COP was only 78% effective across the blood-joint interface. Hyperosmolar solutions of small solutes (e.g., glucose) generated transient osmotic flows across the blood-joint barrier, but far less effectively than albumin. The hydraulic permeability of synovium increased at pathological intra-articular pressures--a phenomenon of potential importance to effusion kinetics.
authors: Department of Physiology, St George's Hospital Medical School, London.
authors: J R
authors: JR
authors: Levick
authors: A D
authors: AD
authors: Knight
mesh_terms: D000818:Animals; D001794:Blood Pressure; D002199:Capillary Permeability; D005947:Glucose / Q000502:physiology; D008833:Microcirculation; D009997:Osmotic Pressure; D011817:Rabbits; D012709:Serum Albumin / Q000502:physiology; D013582:Synovial Fluid / Q000502:physiology; D013583:Synovial Membrane / Q000098:blood supply / Q000502:physiology*
chemical_list: D012709:Serum Albumin; D005947:Glucose