Sanz-Ramos Patricia, Duart Julio, Rodríguez-Goñi María Victoria, Vicente-Pascual Mikel, Dotor Javier, Mora Gonzalo, Izal-Azcárate Iñigo
Laboratory for Orthopaedic Research, School of Medicine, Ed. Los Castaños, University of Navarra, Irunlarrea 1, 31008 Pamplona, Navarra, Spain. E-mail address for I. Izal-Azcárate:
Trauma and Orthopaedic Surgery, Servicio Navarro de Salud, Irunlarrea 3, 31008 Pamplona, Navarra, Spain.
J Bone Joint Surg Am. 2014 Jul 2;96(13):1109-1117. doi: 10.2106/JBJS.M.00271.
The use of autologous chondrocytes in cartilage repair is limited because of loss of the cartilage phenotype during expansion. The mechanosensing capacity of chondrocytes suggests evaluating the use of soft substrates for in vitro expansion. Our aim was to test the expansion of chondrocytes on collagen hydrogels to improve their capacity for chondrogenesis after a number of passages.
Rat cartilage cells were expanded on collagen hydrogels and on plastic, and the preservation of their chondrogenic capacity was tested both in vitro and in vivo. The expression of relevant markers during expansion on each surface was measured by real-time PCR (polymerase chain reaction). Expanded cells were then implanted in focal lesions in the medial femoral condyle of healthy sheep, and the newly formed tissue was analyzed by histomorphometry.
Compared with cells cultured on plastic, cells cultured on hydrogels had better maintenance of the expression of the Sox9, Col2 (type-II collagen), FGFR3, and Alk-5 genes and decreased expression of Alk-1 and BMP-2. Pellets also showed increased expression of the cartilage marker genes aggrecan, Sox9, and Col2, and decreased expression of Col1 and Col10 (type-I and type-X collagen). ELISA (enzyme-linked immunosorbent assay) also showed a higher ratio of type-II to type-I collagen in pellets formed from cells expanded on hydrogels. When sheep chondrocytes were expanded and implanted in cartilage lesions in the femoral condyle of healthy sheep, hydrogel-expanded cells produced histologically better tissue compared with plastic-expanded cells.
The expansion of chondrocytes on collagen hydrogels yielded cells with an improved chondrogenic capacity compared with cells expanded on plastic.
The study results favor the use of hydrogel-expanded cells over the traditional plastic-expanded cells for autologous chondrocyte implantation.
自体软骨细胞在软骨修复中的应用受到限制，因为在扩增过程中软骨表型会丧失。软骨细胞的机械传感能力提示可评估使用软质底物进行体外扩增。我们的目的是测试软骨细胞在胶原蛋白水凝胶上的扩增情况，以提高其传代后的软骨形成能力。
将大鼠软骨细胞在胶原蛋白水凝胶和塑料上进行扩增，并在体外和体内测试其软骨形成能力的保留情况。通过实时聚合酶链反应（PCR）测量在每个表面扩增过程中相关标志物的表达。然后将扩增后的细胞植入健康绵羊股骨内侧髁的局灶性损伤处，通过组织形态计量学分析新形成的组织。
与在塑料上培养的细胞相比，在水凝胶上培养的细胞Sox9、Col2（II型胶原蛋白）、FGFR3和Alk - 5基因的表达维持得更好，而Alk - 1和BMP - 2的表达降低。细胞团中软骨标志物基因聚集蛋白聚糖、Sox9和Col2的表达也增加，而Col1和Col10（I型和X型胶原蛋白）的表达降低。酶联免疫吸附测定（ELISA）也显示，由在水凝胶上扩增的细胞形成的细胞团中II型与I型胶原蛋白的比例更高。当绵羊软骨细胞在健康绵羊股骨髁的软骨损伤处进行扩增和植入时，与在塑料上扩增的细胞相比，水凝胶扩增的细胞产生的组织在组织学上更好。
与在塑料上扩增的细胞相比，软骨细胞在胶原蛋白水凝胶上的扩增产生了软骨形成能力得到改善的细胞。
该研究结果支持在自体软骨细胞植入中使用水凝胶扩增的细胞而非传统的塑料扩增的细胞。
