title: Prolonged in vitro precultivation alleviates post-implantation inflammation and promotes stable subcutaneous cartilage formation in a goat model.
abstract: Synthetic biodegradable scaffolds such as polylactic acid coated polyglycolic acid (PLA-PGA) are especially suitable for engineering shaped cartilage such as auricle, but they induce a serious inflammatory reaction particularly in the immunologically aggressive subcutaneous site, leading to resorption of the engineered autologous cartilage. Our previous study in a rabbit model has demonstrated 2 weeks of in vitro precultivation could significantly alleviate the post-implantation inflammation induced by PLA-PGA engineered cartilaginous grafts, but reproduction of this result failed in a preclinical goat model. The aims of the current study were to investigate whether prolonged in vitro precultivation could form a mature cartilaginous graft to resist the acute host response and promote stable subcutaneous cartilage formation in a preclinical goat model. Goat chondrocytes were seeded onto PLA-PGA scaffolds, in vitro precultivated for 2, 4, 8, and 12 weeks, and then implanted subcutaneously in autologous goats for 1 and 8 weeks. The in vitro engineered cartilage (vitro-EC) was examined histologically (hematoxylin and eosin, safranin-O, collagen II). The 1 week explants were examined histologically and stained for CD3, CD68, collagen I, and apoptosis. The 8 week explants were evaluated by histology, wet weight, volume, glycosaminoglycan (GAG) quantification and Young's modulus. With prolonged in vitro time, the quality of vitro-EC improved and the amount of scaffold residue decreased; more pronounced cartilage formation with fewer immune cells (CD3 and CD68 positive), apoptotic cells, and less collagen I expression were observed in explants that had been in vitro precultivated for a longer period. The subcutaneously regenerated neocartilage became more mature after prolonged implantation. These results suggested that prolonged in vitro precultivation allowed formation of a mature cartilaginous graft to resist the acute host response and promoted stable subcutaneous cartilage formation in autologous goats. These findings may provide useful reference for engineering auricle, trachea, nose, and eyelid shaped cartilage, for example.
authors.affiliation: Shanghai 9th People's Hospital, School of Medicine, Shanghai Key Laboratory of Tissue Engineering, Shanghai Jiao Tong University, 639 Zhi Zao Ju Road, Shanghai, People's Republic of China. Institute of Dermatology, Chinese Academy of Medical Sciences, Nanjing, People's of Republic of China. These authors contributed equally to this work.
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
authors.forename: Dan
authors.initials: D
authors.lastname: Li
authors.forename: Zongqi
authors.initials: Z
authors.lastname: Yin
authors.forename: Xusong
authors.initials: X
authors.lastname: Luo
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Wenjie
authors.initials: W
authors.lastname: Zhang
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Zhang
authors.forename: Yilin
authors.initials: Y
authors.lastname: Cao
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.forename: Guangdong
authors.initials: G
authors.lastname: Zhou
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D017209:Apoptosis; D001672:Biocompatible Materials / Q000737:chemistry*; D002358:Cartilage, Articular / Q000502:physiology*; D019902:Chondrocytes / Q000166:cytology; D005260:Female; D006041:Goats; D007249:Inflammation; D019344:Lactic Acid / Q000737:chemistry*; D008297:Male; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds
chemical_list: D001672:Biocompatible Materials; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid