Assessment of aerobic capacity during swimming exercise in ob/ob mice

Abstract

Obesity is a highly prevalent condition associated with several diseases. Physical exercise has been considered as a non-pharmacological tool in the treatment of obesity. However, several aspects underlying exercise evaluation and prescription in obesity and associated pathologies are still under investigation. Although many research involving exercise have been performed in animal models, there is a lack of protocols for aerobic capacity assessment in obese animals, such as the ob/ob mice. This study aimed the following: (i) to verify the possibility of determining the lactate threshold (LT) on swimming exercise in ob/ob mice and in non-obese heterozygote mice (ob/OB), through visual inspection (vLT) and polynomial adjustment (pLT); and (ii) to verify if the LT determined through these protocols corresponds to the maximal lactate steady state (MLSS). Eight ob/ob and ten ob/OB mice performed an incremental exercise test to determine vLT and pLT as well as constant-load exercise bouts to determine MLSS. There were no within-group differences between vLT, pLT and MLSS [ob/ob: ~5.3% body weight (BW); ob/OB: ~3·6%BW] with a high agreement among protocols. In conclusion, the identification of the LT and MLSS intensities was possible for both groups. These data suggest that the proposed protocols may be used in new research on the effects of different exercise intensities on some aspects of obesity.

Effects of acute exercise over heart proteome from monogenic obese (ob/ob) mice

“…The significantly higher values of % body weight verified in MLSS (ob/OB 4.6 ± 0.5 vs. ob/ob 2.4 ± 0.5, P ≤ 0.05) and IT (ob/OB 2.7 ± 1.2 vs. ob/ob 4.2 ± 0.5, P ≤ 0.05) of ob/ob compared to ob/OB may be resultant by the greater volume of adipose tissue of the homozygote mice, which may facilitate animal fluctuation during exercise. This hypothesis has also been discussed by Almeida et al (2011) that have reported similar data. These authors indicated that the higher MLSS %BW from ob/ob compared to ob/OB mice does not indicate a higher aerobic capacity, been a consequence of the higher body fat percentage.…”

“…One important reason for the reduced number of animals is the difficulty to obtain ob/ob mice, once these leptin‐deficient mice are infertile. Thus its necessary the use of heterozygote animals for breeding leading to an time consuming and final pups of 75% of lean and 25% of obese mice (Almeida et al, 2011). The reduced number of ob/ob obese pups leads to a difficulty to obtain higher isogenic sample size.…”

“…Moderate and high swimming exercises were defined according to maximal lactate steady state threshold (MLSS), considered the gold standard in aerobic fitness assessment (Beneke et al, 2011). MLSS determination was in accordance with the protocol used by Almeida et al (2011). Moderate intensity exercise session was performed by one bout of 20 min of swimming with an overload representing 90% of MLSS.…”

“…Moderate intensity exercise session was performed by one bout of 20 min of swimming with an overload representing 90% of MLSS. High intensity exercise was performed by a single incremental workload test adapted by Cunha et al (2009) and recently also previously performed in ob/ob mice by Almeida et al (2011). Prior to the exercise session and aiming to minimize the animals stress without promoting physiological adaptations derived from exercise, all animals prepared for the single bout of exercise were submitted to water environment.…”

Role of exercise intensity on GLUT4 content, aerobic fitness and fasting plasma glucose in type 2 diabetic mice

“…However, the response of GLUT4 to exercise training performed at distinct intensities has not yet been investigated. LT determination is possible in humans and rodents by several methods, thus facilitating studies in animal models.…”