AJP - Regulatory, Integrative and Comparative Physiology, Vol 265, Issue 2 376-R384, Copyright © 1993 by American Physiological Society
Experimental cachexia: effects of MCA sarcoma in the Fischer rat
B. K. Smith, C. A. Conn and M. J. Kluger
School of Nursing, University of Michigan, Ann Arbor 48109.
Temporal patterns of the cachectic effects of tumor growth and their
relation to systemic levels of tumor necrosis factor (TNF) and IL-6
(interleukin-6) were examined in a rat model of experimental cancer
cachexia employing the methylcholanthrene (MCA) sarcoma. Fischer 344 rats,
implanted with biotelemeters for measuring temperature and activity, were
implanted subdermally with tumor tissue fragments. Ad libitum-fed and
pair-fed controls were sham incised. Bioassays for TNF and IL-6 were
performed on serial plasma samples, obtained via jugular vein at 3- to
6-day intervals throughout the experimental period. Tumor growth induced
significant anorexia, weight loss, and a decline in motor activity
corresponding to an increase in mean plasma IL-6 levels, independent of
reduced food intake or weight loss alone as shown in pair-fed controls. A
significant lowering of body temperature then developed, followed by a two-
to threefold increase in water consumption. The patterns of weight loss and
temperature reduction differed in rate and degree from those seen with pair
feeding.
