ObjectivesThe goals of this study were: 1) to determine if high-fat diet (HFD) feeding in female mice would negatively impact biomechanical and histologic consequences on the Achilles tendon and quadriceps muscle; and 2) to investigate whether exercise and branched-chain amino acid (BCAA) supplementation would affect these parameters or attenuate any negative consequences resulting from HFD consumption.MethodsWe examined the effects of 16 weeks of 60% HFD feeding, voluntary exercise (free choice wheel running) and BCAA administration in female C57BL/6 mice. The Achilles tendons and quadriceps muscles were removed at the end of the experiment and assessed histologically and biomechanically.ResultsHFD feeding significantly decreased the Achilles tendon modulus without histological alterations. BCAA administration significantly decreased the stiffness of Achilles tendons in the exercised normal diet mice. Exercise partially ameliorated both the weight gain and glucose levels in the HFD-fed mice, led to a significant decrease in the maximum load of the Achilles tendon, and an increase in the average fibril diameter of the quadriceps femoris muscle. There were significant correlations between body weight and several biomechanical properties, demonstrating the importance of controlling obesity for maintaining healthy tendon properties. ConclusionsIn summary, this study showed a significant impact of obesity and body weight on tendon biomechanical properties with limited effects of exercise and BCAAs.Cite this article: Bone Joint Res 2013;2:186–92.
Exercise is an inexpensive intervention that may be used to reduce obesity and its consequences. In addition, many individuals who regularly exercise utilize dietary supplements to enhance their exercise routine and to accelerate fat loss or increase lean mass. Branched-chain amino acids (BCAAs) are a popular supplement and have been shown to produce a number of beneficial effects in rodent models and humans. Therefore, we hypothesized that BCAA supplementation would protect against high fat diet (HFD)-induced glucose intolerance and obesity in mice with and without access to exercise. We subjected 80 female C57BL/6 mice to a paradigm of HFD feeding, exercise in the form of voluntary wheel running, and BCAA supplementation in the drinking water for 16 weeks (n = 10 per group). Body weight was monitored weekly, while food and water consumption were recorded twice weekly. During the 5th, 10th, and 15th weeks of treatment, glucose tolerance and body composition were analyzed. Exercise significantly improved glucose tolerance in both control-fed and HFD-fed mice. BCAA supplementation, however, did not significantly alter glucose tolerance in any treatment group. While BCAA supplements did not improve lean to fat mass ratio in sedentary mice, it significantly augmented the effects of exercise on this parameter.
Maternal high-fat diet consumption and obesity have been shown to program long-term obesity and lead to impaired glucose tolerance in offspring. Many rodent studies, however, use non-purified, cereal-based diets as the control for purified high-fat diets. In this study, primiparous ICR mice were fed purified control diet (10–11 kcal% from fat of lard or butter origin) and lard (45 or 60 kcal% fat) or butter (32 or 60 kcal% fat)-based high-fat diets for 4 weeks before mating, throughout pregnancy, and for 2 weeks of nursing. Before mating, female mice fed the 32 and 60% butter-based high-fat diets exhibited impaired glucose tolerance but those females fed the lard-based diets showed normal glucose disposal following a glucose challenge. High-fat diet consumption by female mice of all groups decreased lean to fat mass ratios during the 4th week of diet treatment compared with those mice consuming the 10–11% fat diets. All females were bred to male mice and pregnancy and offspring outcomes were monitored. The body weight of pups born to 45% lard-fed dams was significantly increased before weaning, but only female offspring born to 32% butter-fed dams exhibited long-term body weight increases. Offspring glucose tolerance and body composition were measured for at least 1 year. Minimal, if any, differences were observed in the offspring parameters. These results suggest that many variables should be considered when designing future high-fat diet feeding and maternal obesity studies in mice.
In a historical sense, the study of anatomy has long been a tactile, physical, and extant art: using the hands and eyes to study the human body, often in the form of a theatrical spectacle based on cadaver dissection (de Carvalho Filho et al., 2021;Brenna, 2022).Well into the modern era, little has changed about learning anatomical sciences. Students (university students of all levels, including professional students of medicine and science) study under skilled masters (anatomy faculty) in small-group settings to learn the form of the body. Many of those students, especially doctoral students, may go on to train others in the fine art of dissection, perpetuating the well-established tradition of learning in a master/journeyman/ apprentice model.
While metabolic disorders such as obesity and diabetes are costly and deadly to the current population, they are also extremely detrimental to the next generation. Much of the current literature focuses on the negative impact of poor maternal choices on offspring disease, while there is little work examining maternal behaviors that may improve offspring health. Research has shown that voluntary maternal exercise in mouse models improves metabolic function in offspring. In this study, we hypothesized that controlled maternal exercise in a mouse model will effect positive change on offspring obesity and glucose homeostasis. Female mice were separated into three groups: home cage, sedentary, and exercise. The sedentary home cage group was not removed from the home cage, while the sedentary wheel group was removed from the cage and placed in an immobile wheel apparatus. The exercise group was removed from the home cage and run on the same wheel apparatus but with the motor activated at 5–10 m/min for 1 h/d prior to and during pregnancy. Offspring were subjected to oral glucose tolerance testing and body composition analysis. There was no significant difference in offspring glucose tolerance or body composition as a consequence of the maternal exercise intervention compared to the sedentary wheel group. There were no marked negative consequences of the maternal controlled exercise intervention. Further research should clarify the potential advantages of the controlled exercise model and improve experimental techniques to facilitate translation of this research to human applications.
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