Cartilage is capable of withstanding high shear and compressive stress without damage, but its homeostasis is easily disturbed, causing tissue degradation. Reversal of this damage is almost impossible due to the low cell count and perfusion rate of the tissue. It has been shown, however, that certain cytokines are capable of inhibiting and even reversing tissue degradation. For example, insulin-like growth factors are known to stimulate proteoglycan biosynthesis and inhibit matrix degradation.

Currently, two insulin-like growth factors are known:​ IGF-I and IGF-II. Both of these cytokines were found to stimulate tissue regeneration in vitro, even though in vivo studies have been unsuccessful due to the slow transport of the growth factors to the target cells. It has also been established that growth factors bind to the tissue in much greater amounts than those accounted for by cell receptor binding. The exact binding sites, however, are still unknown.

Research has shown that IGF-II has a higher affinity for binding sites than IGF-I, and can therefore successfully compete with IGF-I. The goal of this study was to describe the kinetics of transport and binding of these growth factors in cartilage. While there have been some previous studies on the transport of IGF-I in bovine and human cartilage, there is little information on transport of IGF-II. The diffusivity of IGF-II was measured to be on the order of 10^-7 cm²/s, and the characteristic lag time was approximately 180 minutes for a 350pm thick cartilage disk. These parameters characterize the fundamental chemical and mechanical kinetics of IGF transport within the tissue. Future studies will focus on further characteristics of macromolecular transport within cartilage.