title: Coupling plowing of cartilage explants with gene expression in models for synovial joints.
abstract: Articular cartilage undergoes complex loading modalities generally including sliding, rolling and plowing (i.e. the compression by a condyle normally to the tissue surface under simultaneously tangential displacement, thus generating a tractional force due to tissue deformation). Although in in vivo studies it was shown that excessive plowing can lead to osteoarthritis, little quantitative experimental work on this loading modality and its mechanobiological effects is available in the literature. Therefore, a rolling/plowing explant test system has been developed to study the effect on pristine cartilage of plowing at different perpendicular forces. Cartilage strips harvested from bovine nasal septa of 12-months-old calves were subjected for 2h to a plowing-regime with indenter normal force of 50 or 100 N and a sliding speed of 10 mm s(-1). 50 N produced a tractional force of 1.2±0.3N, whereas 100 N generated a tractional force of 8.0±1.4N. Furthermore, quantitative-real-time polymerase chain reaction experiments showed that TIMP-1 was 2.5x up-regulated after 50 N plowing and 2x after 100 N plowing, indicating an ongoing remodeling process. The expression of collagen type-I was not affected after 50 N plowing but it was up-regulated (6.6x) after 100 N plowing, suggesting a possible progression to an injury stage of the cartilage, as previously reported in cartilage of osteoarthritic patients. We conclude that plowing as performed by our mimetic system at the chosen experimental parameters induces changes in gene expression depending on the tractional force, which, in turn, relates to the applied normal force.
authors: Clinic of Masticatory Disorders, Removable Prosthodontics and Special Care, Center of Dental Medicine, University of Zurich Plattenstrasse 11 CH-8032 Zurich, Switzerland.
authors: Maria Rita
authors: MR
authors: Correro-Shahgaldian
authors: Vera
authors: V
authors: Colombo
authors: Nicholas D
authors: ND
authors: Spencer
authors: Franz E
authors: FE
authors: Weber
authors: Thomas
authors: T
authors: Imfeld
authors: Luigi M
authors: LM
authors: Gallo
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002356:Cartilage / Q000378:metabolism*; D002358:Cartilage, Articular / Q000502:physiology*; D002417:Cattle; D005786:Gene Expression Regulation / Q000502:physiology*; D066298:In Vitro Techniques; D010003:Osteoarthritis / Q000209:etiology; D060888:Real-Time Polymerase Chain Reaction; D013582:Synovial Fluid; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000235:genetics; D015854:Up-Regulation / Q000235:genetics; D016474:Weight-Bearing
chemical_list: D019715:Tissue Inhibitor of Metalloproteinase-1