Transport and binding of insulin-like growth factor I through articular cartilage

摘要: Abstract This study focused on the role of insulin-like growth factor (IGF) binding proteins (IGFBPs) in cartilage transport and IGF-I within tissue. We have developed experimental theoretical modeling techniques to quantify contrast roles diffusion, binding, fluid convection, electrical migration Bovine articular disks were equilibrated buffer containing 125I-IGF-I graded levels unlabeled IGF-I. Equilibrium as measured by uptake ratio tissue (free plus bound) concentration labeled species buffer, was found be consistent with a first-order reversible model involving one dominant family sites matrix. Western ligand blots revealed major IGF doublet around 23 kDa, which has been previously shown coincide IGFBP-6. Diffusive through diffusion-limited reaction incorporating binding. Addition excess amounts during steady state resulted release bound from tissue, predicted diffusion–reaction model. In contrast, addition low-affinity Des(1-3)IGF-I analog did not result 125I-IGF-I. Application electric current used augment via electroosmosis electrophoresis. Taken together, our results suggest that single substrate family, high-affinity IGFBPs, is responsible for much observed cartilage. The data intratissue flow, such induced mechanical loading vivo may expected enhance an order magnitude this increment help counterbalance restrictions encountered immobilization IGFs proteins.