Histological and biochemical characteristics of the rabbit anterior cruciate ligament in comparison to potential autografts
Mariann Hoyer1,2, Carola Meier3, Benjamin Kohl3, Anke Lohan4, Maria Kokozidou5 and Gundula Schulze-Tanzil5
1Department of Bioanalytics, Technical University, Berlin, 2Central Laboratory, DRK Manniske-Hospital Bad Frankenhausen, Bad Frankenhausen/Kyffhäuser, 3Department of Orthopaedic, Trauma and Reconstructive Surgery, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, 4Forschungseinrichtung für Experimentelle Medizin, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin and 5Department of Anatomy, Paracelsus Medical University, Nuremberg, Germany
Offprint requests to: Gundula Schulze-Tanzil, VMD, Institute of Anatomy, Paracelsus Medical University, Salzburg and Nuremberg, Germany, Prof. Ernst Nathan Str. 1, 90419 Nuremberg, Germany. e-mail: gundula.schulze@pmu.ac.at or gundula.schulze-tanzil@klinikum-nuernberg.de
Summary. Tissue engineering of an anterior cruciate ligament (ACL) implant with ACL cells requires detailed analysis of the tissue characteristics that should be mimicked. Therefore, we studied the histological and biochemical properties of rabbit derived ACLs in comparison to other knee-associated tendons that are used as autografts in men.
Rabbit derived ACLs and Musculus (M.) semimem-branosus, M. semitendinosus tendons and patellar ligaments were explanted from adult New Zealand white rabbits and analyzed histologically for tissue organization (e.g. cellularity, nuclear shapes, elastic fibers), total collagen and sulfated glycosamino-glycan (sGAG) contents. Gene expression analysis was performed for the main extracellular matrix (ECM) components type I collagen, decorin and the glycoprotein tenomodulin.
The ACLs had an average dimension of 1.39x0.39x0.1 cm in situ. They were characterized by high sGAG content in comparison to the other tendons/ligaments, whereas the total collagen content did not differ. ACLs possessed higher cellularity and lower feret diameter of the cell nuclei compared with the investigated rabbit-derived tendons. In ACLs long elastic fibers were observed. Concerning the gene expression level, lower transcription of tenomodulin was detected in the ACL compared with the other tendons, without significant difference in the decorin gene expression. The M. semitendinosus tendon had a significantly higher type I collagen expression than the ACL and the other investigated tendons.
This phenotypical characterization of the lapine ACL presented in this study provides some key standards to evaluate tissue engineered ACL constructs to be tested in the rabbit model. Histol Histopathol 31, 867-877 (2016)
Key words: Anterior cruciate ligament, Patellar ligament, Autograft, New Zealand White Rabbit, TNMD
DOI: 10.14670/HH-11-723