Heterogeneous mechanical response of rat knee menisci to thermomechanical stress
Zernicke, R.F.; Vailas, A.C.; Shaw, S.R.; Bogey, R.A.; Hart, T.J.; Matsuda, J.
American Journal of Physiology 250(1 Pt 2): R65-R70
1986
ISSN/ISBN: 0002-9513 PMID: 3753636 Document Number: 285373
Thermodilatometric, dynamic thermomechanical, and light microscopic analyses were done on the anterior and posterior regions of the rat knee menisci to correlate regional differences in morphology and extracellular matrix composition with regional mechanical behaviour. Following the administration of a general anesthesic, menisci were excised from 12 young female Sprague-Dawley rats. During thermodilatometric and thermomechanical testing, tissue temperature was increased at a constant rate of 3.5.degree. C/min from 30 to 100.degree. C. Kight microscopy revealed regional differences in cell density and proteoglycan content. The anterior horn was significantly heavier (> 87%) and thicker (> 60%) than the posterior region. During thermal analyses, both the anterior and posterior horns decreased in tissue thickness as the temperature increased from 30 to 73.degree. C. After 73.degree. C, however, the posterior horn expanded significantly, whereas the anterior remained in a comparatively contracted state. The rates of linear contraction and expansion fo the posterior horn were seven times those of the anterior horn, and the stiffness of the anterior horn was significantly greater than the posterior horn.