Effect of acute mid-intensity treadmill exercise on the androgen hormone level and uncoupling protein-1 expression in brown fat tissue of mouse

Inhibition of CX3CL1 by treadmill training prevents osteoclast-induced fibrocartilage complex resorption during TBI healing

Introduction

The healing of tendon-bone injuries is very difficult, often resulting in poor biomechanical performance and unsatisfactory functional recovery. The tendon-bone insertion has a complex four distinct layers structure, and previous studies have often focused on promoting the regeneration of the fibrocartilage layer, neglecting the role of its bone end repair in tendon-bone healing. This study focuses on the role of treadmill training in promoting bone regeneration at the tendon-bone insertion and its related mechanisms.

Methods

After establishing the tendon-bone insertion injury model, the effect of treadmill training on tendon-bone healing was verified by Micro CT and HE staining; then the effect of CX3CL1 on osteoclast differentiation was verified by TRAP staining and cell culture; and finally the functional recovery of the mice was verified by biomechanical testing and behavioral test.

Results

Treadmill training suppresses the secretion of CX3CL1 and inhibits the differentiation of local osteoclasts after tendon-bone injury, ultimately reducing osteolysis and promoting tendon bone healing.

Discussion

Our research has found the interaction between treadmill training and the CX3CL1-C3CR1 axis, providing a certain theoretical basis for rehabilitation training.

Mitochondrial Uncoupling: A Key Controller of Biological Processes in Physiology and Diseases

Mitochondrial uncoupling can be defined as a dissociation between mitochondrial membrane potential generation and its use for mitochondria-dependent ATP synthesis. Although this process was originally considered a mitochondrial dysfunction, the identification of UCP-1 as an endogenous physiological uncoupling protein suggests that the process could be involved in many other biological processes. In this review, we first compare the mitochondrial uncoupling agents available in term of mechanistic and non-specific effects. Proteins regulating mitochondrial uncoupling, as well as chemical compounds with uncoupling properties are discussed. Second, we summarize the most recent findings linking mitochondrial uncoupling and other cellular or biological processes, such as bulk and specific autophagy, reactive oxygen species production, protein secretion, cell death, physical exercise, metabolic adaptations in adipose tissue, and cell signaling. Finally, we show how mitochondrial uncoupling could be used to treat several human diseases, such as obesity, cardiovascular diseases, or neurological disorders.

Role of dihydrotestosterone in whole-body energy utilization during acute running exercise in mice

PURPOSE

Dihydrotestosterone (DHT) plays an important role in various processes that utilize energy, including fat and carbohydrate oxidation. The purpose of this study was to determine the effect of inhibiting DHT formation during mid-intensity running exercise on energy expenditure and fat and carbohydrate oxidation in the whole body using a calorimetric chamber.

METHODS

Twelve ICR adult male mice, 9 weeks of age, were randomized into two groups: CON (n = 6, no treatment with exercise) and CONIN (n = 6, DHT inhibitor treatment with exercise, SRD5A1A2 is an enzyme involved in the metabolism of free testosterone into DHT). Inhibitor was administered to the CONIN group intraperitoneally, while the CON group was treated with vehicle (corn oil 2 mg/kg). After 3 days of administration of the inhibitor or vehicle, exercise was performed at 60-70% VO2max for 30 min on a treadmill in a calorimetric chamber. The O2 uptake, CO2 production, carbohydrate and fat oxidation, and respiratory exchange ratio (RER) during 30-min exercise were measured using a calorimeter.

RESULTS

During a single bout of exercise, the CONIN group showed a significantly higher area under the curve (AUC) of O2 uptake and CO2 production from 20 min into exercise than the CON group (p < 0.001). The CONIN group showed a significantly higher AUC for carbohydrate oxidation from 20 min into exercise than the CON group (p < 0.001), whereas no difference was found in fat oxidation between groups (p = 0.067). The CONIN group had a significantly higher AUC of RER from 20 min into exercise than the CON group (p < 0.001).

CONCLUSION

We observed increased energy consumption at the later phase of 30-min moderate-intensity treadmill running when DHT production was inhibited. Furthermore, when DHT production during exercise was inhibited, whole-body fat utilization was inhibited and carbohydrate oxidation was substantially increased at the later phase of exercise compared to in the control group. Therefore, changes in DHT concentration in the body during exercise may be involved in whole-body fat utilization, suggesting that DHT may be an important factor affecting endurance exercise capacity.