Biocompatibility of NDGA-polymerized collagen fibers. II. Attachment, proliferation, and migration of tendon fibroblasts in vitro

The material properties of collagen fibers polymerized with nordihydroguaia retic acid (NDGA) are equivalent to native tendon, suggesting that NDGA cro sslinking may provide a viable approach to stabilizing collagenous material s for use in repairing ruptured, lacerated, or surgically transected fibrou s tissues, such as tendons and ligaments (Koob & Hemandez, Biomaterials, in press). The present study evaluated the biocompatibility of these fibers w ith cultured bovine tendon fibroblasts. Fibroblast attachment, migration, a nd proliferation on NDGA-crosslinked materials were compared to those on pr epolymerized type I tendon collagen constructs as well as on tissue-culture -treated plastic. Fibroblast attachment on NDGA-crosslinked collagen fibril s was equivalent to attachment on plates coated with collagen alone. Over a period of 8 days in culture, attached fibroblasts proliferated on NDGA-cro sslinked collagen at a rate identical to that of fibroblasts attached to na tive collagen, in order for the biomaterial effectively to bridge gaps in f ibrous tissues, fibroblasts must be able to migrate and replicate on the br idging fiber. Control and crosslinked fibers were inserted in calf tendon e xplants, with a portion of the fiber extending out of the sectioned end of the tendon. Explants were cultured for 9 weeks, and the number of cells was measured at weekly intervals. Cells appeared on the fibers after 1 week of culture. By 2 weeks, cells had colonized the entire fiber. The number of c ells continued to increase throughout the 9 weeks in culture, forming a lay er several cells thick. Histologic analysis indicated that the fibroblasts populating the fibers appeared to originate in the epitenon. There was no d ifference in the rate of fibroblast migration and replication, nor in the u ltimate number of colonizing cells, between control collagen fibers and NDG A-crosslinked fibers. NDGA-crosslinked fibers may provide a means of bridgi ng gaps in ruptured, lacerated, or surgically transected tendons by providi ng a mechanically competent scaffold on which tendon fibroblasts can migrat e, attach, and proliferate. (C) 2001 John Wiley & Sons, Inc.