Cartilage Repair Program, Therapeutic Tissue Engineering Laboratory, Department of Orthopaedic Surgery, National University Health System, National University Hospital, Yong Loo Lin School of Medicine, National University of Singapore, 1E, Kent Ridge Road, Singapore, 119288, Singapore.
Clin Orthop Relat Res. 2013 Apr;471(4):1174-85. doi: 10.1007/s11999-012-2487-0.
Management of osteochondritis dissecans remains a challenge. Use of oligo[poly(ethylene glycol)fumarate] (OPF) hydrogel scaffold alone has been reported in osteochondral defect repair in small animal models. However, preclinical evaluation of usage of this scaffold alone as a treatment strategy is limited.
QUESTIONS/PURPOSES: We therefore (1) determined in vitro pore size and mechanical stiffness of freeze-dried and rehydrated freeze-dried OPF hydrogels, respectively; (2) assessed in vivo gross defect filling percentage and histologic findings in defects implanted with rehydrated freeze-dried hydrogels for 2 and 4 months in a porcine model; (3) analyzed highly magnified histologic sections for different types of cartilage repair tissues, subchondral bone, and scaffold; and (4) assessed neotissue filling percentage, cartilage phenotype, and Wakitani scores.
We measured pore size of freeze-dried OPF hydrogel scaffolds and mechanical stiffness of fresh and rehydrated forms. Twenty-four osteochondral defects from 12 eight-month-old micropigs were equally divided into scaffold and control (no scaffold) groups. Gross and histologic examination, one-way ANOVA, and one-way Mann-Whitney U test were performed at 2 and 4 months postoperatively.
Pore sizes ranged from 20 to 433 μm in diameter. Rehydrated freeze-dried scaffolds had mechanical stiffness of 1 MPa. The scaffold itself increased percentage of neotissue filling at both 2 and 4 months to 58% and 54%, respectively, with hyaline cartilage making up 39% of neotissue at 4 months.
Rehydrated freeze-dried OPF hydrogel can enhance formation of hyaline-fibrocartilaginous mixed repair tissue of osteochondral defects in a porcine model.
Rehydrated freeze-dried OPF hydrogel alone implanted into cartilage defects is insufficient to generate a homogeneously hyaline cartilage repair tissue, but its spacer effect can be enhanced by other tissue-regenerating mediators.
骨软骨炎的治疗仍然是一个挑战。已报道在小动物模型的软骨骨缺损修复中单独使用聚[聚（乙二醇）琥珀酸]（OPF）水凝胶支架。然而，作为治疗策略，单独使用这种支架的临床前评估是有限的。
问题/目的：因此，我们（1）分别测定冻干和再水化冻干 OPF 水凝胶的体外孔径和机械硬度；（2）评估在猪模型中，再水化冻干水凝胶植入 2 和 4 个月后的大体缺损填充百分比和组织学发现；（3）分析不同类型的软骨修复组织、软骨下骨和支架的高倍组织学切片；（4）评估新组织填充百分比、软骨表型和 Wakitani 评分。
我们测量了冻干 OPF 水凝胶支架的孔径和新鲜和再水化形式的机械硬度。从 12 只 8 个月大的微型猪中，共有 24 个软骨骨缺损被平均分为支架组和对照组（无支架）。术后 2 和 4 个月进行大体和组织学检查、单因素方差分析和单因素曼-惠特尼 U 检验。
孔径范围为 20 至 433μm。再水化冻干支架的机械硬度为 1MPa。支架本身可使 2 个月和 4 个月时的新组织填充百分比分别增加到 58%和 54%，4 个月时新组织中有 39%为透明软骨。
再水化冻干 OPF 水凝胶可增强猪模型中软骨骨缺损透明纤维软骨混合修复组织的形成。
单独植入软骨缺损的再水化冻干 OPF 水凝胶不足以产生均质透明软骨修复组织，但通过其他组织再生介质可增强其间隔作用。
