Voluntary exercise during chronic renal failure in rats.
OBJECTIVE
Chronic renal failure (CRF) patients often experience a significant degradation in quality of life that is associated with decreased physical fitness. Previous animal studies have used forced running or swimming as modalities to investigate the interactions between exercise and CRF. These modalities generally include stress responses unrelated to the exercise itself. The purpose of the current work was to determine whether, and to what extent, rats experiencing the onset of CRF would participate in voluntary wheel running exercise. An additional objective was to examine physiological parameters related to skeletal muscle and cardiovascular adaptation in the context of CRF and exercise.


METHODS
Groups of rats were assigned to sham-operated or 5/6 nephrectomy groups, and further divided into running or nonrunning subgroups. Blood, heart, and muscle tissues were collected 30 d after the exercise groups were returned to running wheel-equipped cages.


RESULTS
The results demonstrated that rats experiencing the early stages of CRF will voluntarily exercise to the same extent as sham-operated animals (e.g., sham, 7.2+/-0.8 vs CRF, 6.8+/-0.7 km.d). CRF resulted in increased systolic blood pressure that was not normalized by exercise. CRF induced a decrease in hemoglobin concentration that was prevented by exercise. Voluntary running resulted in an apparently nonpathological left ventricular hypertrophy in both the sham-operated and CRF rats. In locomotor skeletal muscles, CRF resulted in a 31% decrease in citrate synthase activity that was completely blunted by voluntary running activity.


CONCLUSIONS
Rats experiencing the onset of CRF will run voluntarily. This exercise appears to provide some potentially palliative effects on the skeletal muscle and cardiovascular responses to CRF.
Adams
Gregory R
GR
Department of Physiology & Biophysics, University of California Irvine, Irvine, CA 92697-4560, USA. GRAdams@uci.edu
Zhan
Chang-De
CD
Haddad
Fadia
F
Vaziri
Nosratola D
ND
D000818:Animals; D005260:Female; D006454:Hemoglobins / Q000378:metabolism; D007676:Kidney Failure, Chronic / Q000097:blood / Q000503:physiopathology*; D009043:Motor Activity / Q000502:physiology; D018482:Muscle, Skeletal / Q000378:metabolism / Q000502:physiology; D009392:Nephrectomy; D005082:Physical Exertion / Q000502:physiology*; D016133:Polymerase Chain Reaction / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley
D006454:Hemoglobins