A direct compression stimulator for articular cartilage and meniscal explants

Adam C. Aufderheide, Kyriacos A. Athanasiou

Research output: Contribution to journalArticle

30 Scopus citations

Abstract

This paper describes the development and use of a direct compression stimulator for culturing explants from the meniscus of the knee and articular cartilage. Following design and fabrication of the instrument along with its data acquisition system, the function of the machine was verified by both mechanical means and tissue effect. The loading chamber can hold up to 45 5 mm diameter samples. While designed to stimulate samples up to 4 mm thick, axial displacements as little as 0.127μm are within the theoretical capacity of the stimulator. In gene expression studies, collagen II and aggrecan expression were examined in explants from articular cartilage as well as medial and lateral menisci subjected to dynamic stimulation and static compression. These results were then compared to free swelling samples. It was found that static compression to cut thickness down-regulated aggrecan and collagen II expression in articular cartilage explants compared to free swelling controls by 94% and 90%, respectively. The application of a dynamic, intermittent, 2% oscillation around the cut thickness returned expression levels to those of free swelling controls at 4h but not at 76h. In medial meniscus samples, dynamic compression up-regulated aggrecan expression by 108%, but not collagen II expression, at 4 and 76h compared to static controls. No difference in gene expression was observed for lateral meniscal explants. Thus, effects of direct compression seen in articular cartilage may not necessarily translate to the knee meniscus. The design of this stimulator will allow a variety of tissues and loading regimens to be examined. It is hoped that regimens can be found that not only return samples to the production levels of free swelling controls, but also surpass them in terms of gene expression, protein synthesis, and functional properties.

Original languageEnglish (US)
Pages (from-to)1463-1474
Number of pages12
JournalAnnals of Biomedical Engineering
Volume34
Issue number9
DOIs
StatePublished - Sep 2006
Externally publishedYes

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Keywords

  • Cartilage explants
  • Direct compression
  • Dynamic stimulation
  • Gene expression
  • Meniscal explants

ASJC Scopus subject areas

  • Biomedical Engineering

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