In vitro and in vivo behaviour of biodegradable and injectable PLA/PGA copolymers related to different matrices.
This study comparatively investigates the in vitro and in vivo behavior of injectable polymeric materials for the treatment of bone defects. The tested materials were three injectable and biodegradable PLA/PGA 50/50 copolymers dispersed in different matrices: Fisograft-gel (GEL) was dispersed in an aqueous matrix of poly-ethyl-glycole (PEG); Slurry2 (SL2) was dispersed in an aqueous matrix of PEG and dextran; and Slurry6 (SL6) was dispersed in a 3% agarose matrix. The biological characterization of these materials was studied by in vitro and in vivo tests: the in vitro test assessed the cellular response in terms of viability, differentiation and synthetic activity, while the in vivo test evaluated the healing capacity of bone defects treated with these biomaterials. GEL and SL2 induced a similar response for viability and differentiation of MG63 osteoblast-like cells after a 7-day culture, while SL6 caused a higher production of both interleukin-6 and type I collagen. Since the results showed that the materials were biocompatible and not cytotoxic in vitro, the in vivo study was carried out: materials were implanted, under general anesthesia, in critical size defects of rabbit femoral condyles; after 4 and 12 weeks, the healing rates and the quality of the regenerated bone were histomorphometrically calculated. The SL2-treated defects healed better at 12 weeks with a more similar microarchitecture of the newly formed bone to normal bone in comparison with other materials, as demonstrated by bone volume fraction and trabecular thickness values.
Tschon
M
M
Experimental Surgery Department, Codivilla-Putti Research Institute, Rizzoli Orthopedic Institute, Bologna - Italy.
Fini
M
M
Giavaresi
G
G
Torricelli
P
P
Rimondini
L
L
Ambrosio
L
L
Giardino
R
R
D020341:Absorbable Implants; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry* / Q000627:therapeutic use; D001847:Bone Diseases / Q000601:surgery; D001861:Bone Regeneration / Q000187:drug effects; D018786:Bone Substitutes / Q000737:chemistry* / Q000627:therapeutic use; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D024042:Collagen Type I / Q000032:analysis; D003911:Dextrans / Q000737:chemistry; D004337:Drug Carriers; D005269:Femur / Q000601:surgery; D006801:Humans; D015850:Interleukin-6 / Q000032:analysis; D019344:Lactic Acid / Q000737:chemistry* / Q000627:therapeutic use; D008422:Materials Testing; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects; D011092:Polyethylene Glycols / Q000737:chemistry; D011100:Polyglycolic Acid / Q000737:chemistry* / Q000627:therapeutic use; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry* / Q000627:therapeutic use; D011817:Rabbits; D012212:Rheology; D012685:Sepharose / Q000737:chemistry; D014945:Wound Healing / Q000187:drug effects
D001672:Biocompatible Materials; D018786:Bone Substitutes; D024042:Collagen Type I; D003911:Dextrans; D004337:Drug Carriers; D015850:Interleukin-6; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D011092:Polyethylene Glycols; D012685:Sepharose