Meniscus cells seeded in type I and type II collagen-GAG matrices in vitro

The objective of this study was to determine the proliferative and biosynth etic activity of calf meniscus cells seeded in type I and type II collagen- glycosaminoglycan (GAG) copolymers with the overall goal to develop a cell- seeded implant for future investigations to improve the regeneration of the knee meniscus. The cell-seeded matrices were digested in protease and anal yzed for GAG by a modification of the dimethyl-methylene blue method and as sayed for DNA content. Other specimens were evaluated histologically after I, 7, 14 and 21 days. Contraction of the same types of matrices, seeded wit h adult canine meniscus cells, was measured at the same time points. After three weeks, cells were observed throughout the type II matrix: whereas the type I matrix was densely populated at the margins. The cell morphology an d the cell density after three weeks in both matrices was consistent with t he normal meniscus, DNA assay for the type I matrix showed a 40% decrease o ver the first week and a final amount of DNA that was not significantly dif ferent from the initial value, whereas the type II matrix doubled its DNA c ontent over the same time period. The cells continued their biosynthesis of GAG and type I collagen. GAG content of the type II matrix increased by 50 % more than the type I matrix after three weeks. Over the same time period, the type I matrix displayed a significant shrinkage to approximately 50% o f its initial value whereas in contrast, the type II matrix and the unseede d controls showed no significant shrinkage. The number of cells and the hig her GAG synthesis in the type II matrix, and its resistance to cell-mediate d contracture, commend it for future investigation of the regeneration of m eniscus in vivo. (C) 1999 Elsevier Science Ltd. All rights reserved.