AJP - Regulatory, Integrative and Comparative Physiology, Vol 250, Issue 1 65-R70, Copyright © 1986 by American Physiological Society
Heterogeneous mechanical response of rat knee menisci to thermomechanical stress
R. F. Zernicke, A. C. Vailas, S. R. Shaw, R. A. Bogey, T. J. Hart and J. Matsuda
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 behavior. Following the
administration of a general anesthetic, 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 degrees
C/min from 30 to 100 degrees C. Light microscopy revealed regional
differences in cell density and proteoglycan content. The anterior horn was
significantly heavier (greater than 87%) and thicker (greater than 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 degrees C. After 73 degrees C, however, the posterior horn
expanded significantly, whereas the anterior remained in a comparatively
contracted state. The rates of linear contraction and expansion of 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.
