(93z) Chondrogenic Differentiation of Rat Mesenchymal Stem Cells on Glycosaminoglycan Augmented Chitosan Membranes

Damaged cartilage is unable to regenerate itself; therefore, there is great interest in methods for regenerating cartilage with biocompatible materials and stem cells. However, an optimal differentiation protocol has not yet been established. Proteoglycans (PGs) synthesized by chondrocytes make up most of the extracellular matrix in cartilage, and glycosaminoglycans (GAGs) dominate the structure and function of PGs. GAGs can be ionically or covalently immobilized on the biopolymer chitosan, a deacetylated form of chitin that is a biocompatible and biodegradable. The goal of this research was to study the affects of GAG-augmented chitosan surfaces on the chondrogenic differentiation of rat MSCs. Three GAGs (hyaluronic acid, chondroitin sulfate A, and heparin) were covalently or ionically immobilized on chitosan surfaces. Rat MSCs were then seeded onto these surfaces and cultured for one week in a proliferation culture medium, followed by 2 weeks in a differentiation medium containing TGF-beta1. In our initial cultures on GAG-chitosan membranes, no PGs/GAGs were detected in the culture medium samples. However, positive staining for PGs/GAGs was observed within aggregates of differentiating MSCs on the membranes. Measurements of specific growth rate using the MTT assay showed much higher cell growth on the ionically immobilized Chondroitin sulfate A surface. This suggests that CSA-chitosan may be an excellent surface for culture of MSC-derived chondrocytes. Currently, culture experiments are being conducted using three-dimensional, GAG-chitosan scaffolds. The results from these experiments will be analyzed and reported.