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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, RESULTS. Meshes: Animals, Body Weight, Cardiomyopathies, Cardiovascular System, Coronary Vessels, Diaphragm, Dose-Response Relationship, Drug, Eating, Heart Failure, In Vitro Techniques, Interleukin-6, Liver, Lung, Male, Motor Activity, Muscle Contraction, Muscle, Skeletal, Muscular Atrophy, Myocardial Contraction, Myocardium, Organ Size, Rats, Rats, Wistar, Recombinant Proteins, Regional Blood Flow.
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Does interleukin-6 cause myocardial failure and skeletal muscle atrophy in rats? Context: The impact of interleukin (IL)-6 on skeletal muscle function remains the subject of controversy. The effects of 7-day subcutaneous administration of recombinant human IL-6 were examined at 3 doses, 50, 100, or 250 microg x kg(-1) x d(-1), in rats. Skeletal muscle mass decreased dose-dependently (with increasing dose: in the diaphragm, -10%, P=NS; -15%, P=0.0561; and -15% P<0.05; and in the gastrocnemius, -9%, P=NS; -9%, P=NS; and -18%, P<0.005) because of decreases in cross-sectional area of all fiber types without alterations in diaphragm contractile properties. Cardiovascular variables showed a dose-dependent heart dilatation (for end-diastolic volume: control, 78 microL; moderate dose, 123 microL; and high dose, 137 microL, P<0.001), reduced end-systolic pressure (control, 113 mm Hg; moderate dose, 87 mm Hg; and high dose, 90 mm Hg; P=0.037), and decreased myocardial contractility (for preload recruitable stroke work: control, 79 mm Hg; moderate dose, 67 mm Hg; and high dose, 48 mm Hg; P<0.001). Lung edema was confirmed by an increased wet-to-dry ratio (control, 4.2; moderate dose, 4.6; and high dose, 4.5; P<0.001) and microscopy findings. These cardiovascular alterations led to decreases in organ blood flow, particularly in the diaphragm (control, 0.56 mL x min(-1) x g(-1); moderate dose, 0.21 mL x min(-1) x g(-1); and high dose, 0.23 mL x min(-1) x g(-1); P=0.037). In vitro recombinant human IL-6 administration did not cause any alterations in diaphragm force or endurance capacity.
assistant
IL-6 clearly caused ventilatory and peripheral skeletal muscle atrophy, even after short-term administration. Blood flow redistribution, resulting from the myocardial failure induced by IL-6, was likely responsible for this muscle atrophy, because IL-6 did not exert any direct effect on the diaphragm. Final Decision: yes