Enzymatic degradation of the intervertebral disc (IVD) with chondroitinase ABC (ChABC) reduces proteoglycan content of the IVD, thus simulating the GAG loss seen clinically in patients suffering from disc degeneration. This approach has been employed in models of disc injury in rats, rabbits and goats when administered over a large range of dosages [1–3]. Moreover, ChABC has also been used to induce repair of herniated discs in rabbits via chemonucleolysis [4, 5]. Despite the effectiveness of ChABC treatment to reduce the GAG content of the IVD, several recent studies including our own, have shown that this GAG loss is reversible at extended time points post enzymatic treatment [2,6,7]. The goal of the current study is to examine the dose dependent response of IVDs to degradation by ChABC in vivo. We hypothesize that administration of ChABC will result in dose dependent GAG loss and reduced mechanical properties. We administered ChABC at 0.1 U/ml, 1.0 U/ml and 10 U/ml and examined the changes in biomechanical properties, biochemical content, and gene expression in order to examine the biophysical and molecular mechanism by which GAG loss occurs in this model.
Histological Features of the Degenerating Intervertebral Disc in a Goat Disc-Injury Model
