AJP - Gastrointestinal and Liver Physiology, Vol 250, Issue 1 70-G75, Copyright © 1986 by American Physiological Society
Actomyosin, collagen, and cell hypertrophy in intestinal muscle after jejunoileal bypass
R. L. Bowers, C. Eeckhout and N. W. Weisbrodt
Previous observations indicate that bypass of 70% of the small bowel of
rats induces increases in the seromuscular mass of both the in-continuity
and the bypassed segment. The purpose of this study was to quantify the
amount of actomyosin and collagen in the muscle layer and to determine the
number of cells per cross-sectional area of the circular muscle layer at
various locations of the small intestine after jejunoileal bypass. The
amount of actomyosin relative to total tissue protein remained the same in
the hypertrophied tissues compared with controls, and the actin-to-myosin
ratios were similar. The collagen content per wet weight of the tissue from
the sham- and bypass-operated animals tended to be less than in tissue from
unoperated controls and was significantly less at the distal in-continuity
location. The number of cells per cross-sectional area was decreased in
tissues from all locations of the bypassed animals. These findings support
the hypothesis that the increase in seromuscular mass after intestinal
bypass is due to an increase in functioning smooth muscle tissue and that
at least part of the increase is due to cell hypertrophy.
