Endurance training modulates lymphocyte function in rats with post-MI CHF.

PURPOSE: Exercise training restores innate immune system cell function in post-myocardial infarction (post-MI) rats. However, studies of the involvement of lymphocyte (Ly) in the setting of the congestive heart failure (CHF) are few. To address this issue, we investigated the function of Ly obtained from cervical lymph nodes from post-MI CHF rats submitted to treadmill running training. METHODS: Twenty-five male Wistar rats were randomly assigned to the following groups: rats submitted to ligation of the left coronary artery, which were sedentary (MI-S, N = 7, only limited activity) or trained (MI-T, N = 6, on a treadmill (0% grade at 13-20 m.m) for 60 min.d, 5 d.wk, for 8-10 wk); or sham-operated rats, which were sedentary (sham-S, N = 6) or trained (sham-T, N = 6). The incorporation of [2-C]-thymidine by Ly cultivated in the presence of concanavalin A (Con A) and lipopolysaccharide (LPS), cytokine production by Ly cultivated in the presence of phytohemagglutinin (PHA), and plasma concentration of glutamine were assessed in all groups, 48 h after the last exercise session. RESULTS: Proliferative capacity was increased, following incubation with Con-A in the MI groups, when compared with the sham counterparts. When incubated in the presence of PHA, MI-S produced more IL-4 (96%) than sham-S (P < 0.001). The training protocol induced a 2.2-fold increase in the production of interleukin-2 (P < 0.001) of the cells obtained from the cervical lymph nodes of MI-T, compared with MI-S. CONCLUSION: The moderate endurance training protocol caused an increase in IL-2 production, and a trend toward the reversion of the Th1/Th2 imbalance associated with IL-4 production increased in the post-MI CHF animal model.

Lipid metabolism in trained rats: effect of guarana (Paullinia cupana Mart.) supplementation.

BACKGROUND AND AIMS: Guarana is widely consumed by athletes, either in supplements or in soft drinks, under the belief that it presents ergogenic and "fat burning" effects. We examined the effect of guarana supplementation (14 days) upon aspects of lipid metabolism in sedentary (C) and trained rats (T). METHODS: To isolate the effect of caffeine from that of other components of guarana, we adopted two different doses of whole extract (G1-0.130 g/kg; G2-0.325 g/kg) or decaffeinated extract (DG1, DG2). Body weight, food and water intake; muscle fat content, oleate incorporation, glycogen content, and carnitine palmitoyltransferase I (CPT I) activity and mRNA expression; along with plasma lactate concentration, were assessed. RESULTS: Muscle oleate incorporation was decreased in rats receiving decaffeinated guarana in relation to G1 and G2; as was CPT I mRNA expression in the gastrocnemius. Whole extract supplementation, but not DG induced reduced plasma lactate concentration in trained rats. G1 showed higher muscle glycogen content compared with all other groups. The results show an effect of guarana on aspects of lipid metabolism, which is abolished by decaffeination. CONCLUSION: The changes in lipid metabolism of supplemented rats herein reported are associated with the methylxanthine content of guarana.

Cardiovascular adaptations in rats submitted to a resistance-training model.

1. The present study sought to evaluate cardiovascular adaptations, such as blood pressure (BP), heart rate (HR) and cardiac hypertrophy, to resistance training (RT) in a rat model. 2. The training protocol consisted of four sets of 10-12 repetitions of the squat exercise performed at 65-75% of one repetition maximum (1RM) over 4 weeks. Animals were randomly divided into three groups: control (n = 8, CO), electrically stimulated (n = 8, ES) and trained (n = 8, TR; also electrically stimulated). Blood pressure and HR were measured by a direct method in conscious rats after the training period. 3. All groups began with similar 1RM and 1RM/bodyweight (BW) ratio, however, at the end of the protocol only the TR group was different from the beginning (56% and 50%, respectively; both P < 0.01). The CO and ES groups had similar values for cardiac chambers weight/BW ratio, HR and diastolic, systolic and mean BP. Left ventricular hypertrophy (LVH) determined by the left ventricle (LV) weight/BW ratio was increased in the TR group (12%) when compared to CO (P < 0.01) or ES groups (P < 0.01). No changes were found in the weights of the atrium or right ventricle. Diastolic (14%) and mean BP (13%) were lower in the TR group (P < 0.05), whereas systolic BP and HR remained unchanged. 4. Collectively these results demonstrate that the rat RT model used is associated with significant development of cardiac hypertrophy and lowering of resting BP. These cardiovascular adaptations seem to a result of the training exercise and not influenced by stress since circulating catecholamine levels and adrenal gland weights remained unchanged in all groups.