physiological function of HA
1. Lubrication and cushion stress
Hyaluronic Acid has the special rheology nature, most meaningful is entrusts with the synovial fluid non-Newtonian fluid the characteristic and the viscoelasticity.When the joint is in the low hit frequency (for example walks normally when), the synovial fluid assumes the coherent solution, to in the joint synovial membrane organization, each organization plane, the ligament and the collagen structure and so on exercises the lubrication function, reduces the organization the friction; When the joint is in the high hit frequency, the synovial fluid transforms by the coherent characteristic into the elastic characteristic, the cushion stress to the joint hit; When the joint carries a heavy load, in the synovial fluid low molecular solute and the moisture content press out from the synovial fluid to the cartilage matrix in, causes the synovial fluid transformation has several micron thickness gelatinous states, transforms by the fluid into the elastomer, acts as slow in the joint gap dies, reduces the pressure which the joint withstands, to the articular cartilage display protective function, also has the protective function to in the cell and the cell membrane receptor.
Hyaluronic Acid and the protein form the compound cover forms thin indefinite form structure level (laminasplenden) in the articular cartilage surface, thickness is 1~10 μm, along with plants is different with the age and is different.This structure has the very strong deformability and the elasticity, may play glide level (slidinglayer) and the absorption stress role, when the joint stress has the glide, this structure may be before the cartilage surface layer to destroy, has the buffer type function, thus display protection cartilage, merit and so on maintenance cartilage matrix integrity
2. Acts as the auxiliaries and with the proliferation barrier
Occurs when the embryonic period body, the ticulare formation is depends on partial Hyaluronic Acid the synthesis to increase, hold certain gap completes.In the normal condition, the joint needs HA the flowing to maintain the ticulare being open for business.The ticulare volume size and periphery organizes the housing the fluid static forcing and the osmotic pressure decided, because HA itself is the result of the osmotic pressure as well as took the proliferation barrier, may adjust other macro-molecule material the transportation, thus adjustable fluid static forcing and speed of flow, therefore plays the decision role to the ticulare volume size.
Hyaluronic Acid forms the macro-molecule network structure sufficiently in the synovial fluid density, adjusts saving water and the macro-molecule material proliferation, acts as a proliferation barrier in the joint, the regulative moisture content and other nutrition ingredient turnover cartilage matrix.The cartilage nutrition is provides by the synovial fluid in nutrition ingredient after the indefinite form structure proliferation to the cartilage surface for it, but under the cartilage the bone does not have the nutrition function to the cartilage.The cartilage cell metabolite and the excreta must penetrate richly including the Hyaluronic Acid cartilage matrix, the cartilage surface indefinite form level proliferation to the synovial fluid, again from the synovial fluid seepage to the synovial membrane, in process synovial membrane intercellular space HA, finally converges in the synovial membrane the capillary vessel to arrive the lymph system to drain, in this process, HA adjusts various material the proliferation speed, thus it can be seen Hyaluronic Acid the vital role which displays to the cartilage nutrition and metabolism.
Hyaluronic Acid to the bacterium, the toxin, the immunity compound and so on the barrier function, protects the cartilage and the synovial membrane exempts the enzyme, the chemical substance as well as the toxin and so on the destruction, stable cell membrane, deactivated cell membrane receptor sensitivity.
3. Pair of cell function control action
Hyaluronic Acid through exercises it with in the matrix and the cell membrane Hyaluronic Acid union protein react to the cell regulative function.TheHyaluronic Acid density and Mr are affect Hyaluronic Acid to the cell function important attribute.The high potency, high MrHyaluronic Acid suppress the blood capillary the production, but low MrHyaluronic Acid may induce the blood vessel production.Some people believed that, under the normal condition, in the ticulare the non-blood vessel production is because its contains highly concentrated, high Mr Hyaluronic Acid the inhibitory action result which produces to the blood vessel.
In the specific situation, the lymphocyte as well as other many kinds of cell membrane may express the HA union protein (acceptor), has the pathological change when the joint, the cell can have the change to the Hyaluronic Acid acceptor expression, but Hyaluronic Acid may take advantage of this affects the cell assembling with the immune response production, thus achieves the suppression inflammation the function.Hyaluronic Acid also may affect in the nerve cell membrane the ache acceptor, has the shielding effect to the acceptor, may alleviate the ache.
4. Street sweeper function
Discovers Hyaluronic Acid from the 20th century 40's to be possible by many kinds of degeneration and so on oxidized system as well as ion radiation.Discovered through several dozens years research that, causes the Hyaluronic Acid chain to have the break cause is the free radical, mainly for hydroxyl free radical.Through with the free radical response, Hyaluronic Acid may become the elimination free radical in vivo the street sweeper.To the joint disease pathology research discovery, the free radical which the oxygen grows (oxygen-derivedfreeradicals, ODFR) is the initiation and the participation pathological change important attribute.According to the material reported that, ODFR may contract in the organization to the knot many macro-molecule material react, creates the organization to damage.In the joint ODFR to the synovial fluid in as well as constitution cartilage PGA the skeletonHyaluronic Acid react, also has the destructive effect to in the cartilage protein polyose and the collagen textile fiber.
Has conducted many research to ODFR to the cartilage cell function.Discoveries and so on Vincent, ODFR may suppress the cartilage cell the growth, also the suppression intensity has the dosage dependence.Discoveries and so on Larsen, ODFR has the destructive effect to the cartilage cell membrane.The cartilage cell exposes in H2O2, may cause the cartilage cell certain enzymes to have the active change, the ATP content reduces obviously. Kvam and so on carries on in vitro experiment discovered, when the cartilage cell processes 16h with ODFR, may destroy the cartilage cell the membrane integrity, but high MrHyaluronic Acid or the Hyaluronic Acid ester derivative may protect the cartilage cell to exempt the ODFR harm.Discoveries and so on Sato, RA and the OA patient synovial fluid elimination oxygen free radical ability enhancement, in synovial fluidHyaluronic Acid has the elimination oxygen free radical, protects the cartilage the function.
Some researchers believed that, Hyaluronic Acid is possibly helpful in joint fast metabolism to the cell fragment elimination, the cell fragment may insert Hyaluronic Acid in the macro-molecule network structure, eliminates along with the Hyaluronic Acid metabolism.