title: Artificial cartilage made from a novel double-network hydrogel: In vivo effects on the normal cartilage and ex vivo evaluation of the friction property.
abstract: This study evaluated the in vivo influence of a poly-(2-Acrylamido-2-methylpropane sulfonic acid)/poly-(N,N'-dimetyl acrylamide) (PAMPS/PDMAAm) double-network (DN) hydrogel on counterface cartilage in rabbit knee joints and its ex vivo friction properties on normal cartilage. In the first experiment, the DN gel was implanted in a surgically created defect in the femoral trochlea of rabbit knee joints and the left knee was used as the control. Evaluations using a confocal laser scanning microscopy demonstrated that the DN gel did not affect the surface microstructure (surface roughness, the number of small pits) of the counterface cartilage in vivo at 4 and 12 weeks. The histology also showed that the DN gel hadno pathological damage on the cartilage matrices and cells at 4 weeks. However, two of the five DN gel-implanted knees showed mild irregularity on the counterface cartilage surface at 12 weeks. In the second experiment, the friction property between the normal and the artificial cartilage was determined using a joint simulator apparatus. The ex vivo mean friction coefficient of the DN gel to normal cartilage was 0.029, while that of the normal-to-normal cartilage articulation was 0.188. The coefficient of the DN gel-to-normal cartilage articulation was significantly lower than that of the normal-to-normal cartilage articulation (p < 0.0001). This study suggested that the PAMPS/PDMAAm DN gel has very low friction coefficient on normal cartilage and has no significant detrimental effects on counterface cartilage in vivo, and can be a promising material to develop the artificial cartilage.
authors.affiliation: Department of Sports Medicine and Joint Surgery, Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
authors.forename: Kazunobu
authors.initials: K
authors.lastname: Arakaki
authors.forename: Nobuto
authors.initials: N
authors.lastname: Kitamura
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Fujiki
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kurokawa
authors.forename: Mikio
authors.initials: M
authors.lastname: Iwamoto
authors.forename: Masaru
authors.initials: M
authors.lastname: Ueno
authors.forename: Fuminori
authors.initials: F
authors.lastname: Kanaya
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Osada
authors.forename: Jian Ping
authors.initials: JP
authors.lastname: Gong
authors.forename: Kazunori
authors.initials: K
authors.lastname: Yasuda
mesh_terms: D000178:Acrylamides / Q000494:pharmacology*; D000818:Animals; D001187:Artificial Organs; D002356:Cartilage / Q000187:drug effects* / Q000473:pathology; D017276:Friction / Q000187:drug effects*; D006614:Hindlimb / Q000187:drug effects / Q000473:pathology / Q000601:surgery; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000494:pharmacology*; D007150:Immunohistochemistry; D008422:Materials Testing; D018613:Microscopy, Confocal; D011108:Polymers / Q000494:pharmacology*; D011817:Rabbits; D013451:Sulfonic Acids / Q000494:pharmacology*; D013499:Surface Properties / Q000187:drug effects
chemical_list: D000178:Acrylamides; D011108:Polymers; D013451:Sulfonic Acids; C429790:poly(N,N-dimethylacrylamide); D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; C077118:poly(2-acrylamido-2-methyl-1-propanesulfonic acid)