Effect of RGD coating on osteocompatibility of PLGA-polymer disks in a rattibial wound

Osteocompatibility of porous polylactic-glycolic acid (PLGA) disks coated w ith synthetic peptides was assessed in 5-mm diameter unicortical tibial oss eous wounds in rats. The coatings consisted of various ratios of peptides i ncluding the tripeptide arginine-glycine-aspartic acid (RGD) and the inacti ve arginine-lycine-glutamic acid (RGE). When left empty, the tibial wounds healed spontaneously with proliferation of intramedullary woven bone within 1 week. The reactive bone was resorbed, and by 3 weeks, the cortical wound was healed with lamellar bone, and the medullary space was repopulated wit h marrow. When PLGA disks were implanted there was a delay in repair with r educed bone fill and no bone bridging at 3 weeks. When disks were coated wi th increasing amounts of RGD peptide, there was a biphasic effect on osteoc ompatibility and on osseous ingrowth. Evaluation at 10 days showed a dose-d ependent increase, with 1.5-fold greater osteocompatibility (p < 0.05) and 1.6-fold more osseous ingrowth into the polymer (p < 0.01) than uncoated di sks. With more RGD and with undiluted RGE, osteocompatibility and osseous i ngrowth were the same as with uncoated disks. At 3 weeks, there were no sig nificant differences among all the groups. These data indicate that RGD coa ting enhanced early stages of osteocompatibility and ingrowth. (C) 2001 Joh n Wiley & Sons, Inc.