Quantification of Chondrocyte Apoptosis in Mechanically Impacted Articular Cartilage

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Title: Quantification of Chondrocyte Apoptosis in Mechanically Impacted Articular Cartilage
Author: Siravuri, Krishi
Advisors: Peter L. Menter, Committee Chair
Abstract: Osteoarthritis is a severely debilitating joint disorder. It is slowly progressing chronic disease and has no precise known causes. Impact injury can lead to cellular and matrix changes in articular cartilage similar to those seen in osteoarthritis. Impact injury models are often used as models for osteoarthritis. The purpose of this study was to use an in vitro impact injury model to examine the distribution and timing of apoptosis cell death following an impact injury. In this study it was hypothesized that there will be an increase in apoptosis cells with increasing impact load; that over time in culture the number of apoptotic cells will increase due to lingering effects from the impaction; and that apoptosis will be most severe directly below the impaction. Paired porcine knees were obtained fresh and patellae were removed using sterile techniques. Controlled mechanical impactions were made on 12 patellae at 25 mm⁄s, using MTS load frame, to pre selected force levels of 1000N (characterized as medium) and 12 patellae were subjected to 2000N (characterized as high). The twelve non-impacted patellae were used as controls. Following impaction, the impact patellae were placed in organ culture for 0, 3, 7, or 14 days and subsequent degenerative changes over time were assessed. Apoptotic cells were quantified using terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) technique. The stained cells were quantified as a percentage of the total number of cells. Changes in percentage of apoptotic cells was analyzed with experimental factors impact level, days in culture ( 0, 3, 7, 14), distance from center of impaction, and depth in tissue. There was a significant depth and time dependent increase in the percentage of apoptotic cells for high impactions. A significant increase in percentage of apoptotic cells was observed from high impactions after 14 days culture time and a significant increase in percentage of apoptotic cells, for 0 days culture time was observed from medium impactions. In conclusion magnitude of load has significant effect on chondrocyte apoptosis throughout the depth of the cartilage tissue, but depends on culture time.
Date: 2007-05-14
Degree: MS
Discipline: Biomedical Engineering
URI: http://www.lib.ncsu.edu/resolver/1840.16/1383

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