A Methionine-Restricted Diet and Endurance Exercise Decrease Bone Mass and Extrinsic Strength but Increase Intrinsic Strength in Growing Male Rats

Abstract

Dietary methionine restriction (MR) has been suggested to be comparable to endurance exercise with respect to its beneficial effects on health. To further investigate the effects of MR and endurance exercise on growing bone, 7-wk-old male Sprague-Dawley rats were fed different l-methionine (Met)-containing diets with or without endurance exercise intervention (Ex; 0.86% Met, 0.52% Met, 0.17% Met, 0.86% Met-Ex, 0.52% Met-Ex, and 0.17% Met-Ex groups). After an 8-wk intervention period, exercise-trained rats had a 9.2% lower body weight (BW) than did sedentary rats (P < 0.05). Additionally, 0.17% Met-fed rats had 32% lower BW when compared with rats fed the other 2 diets (P < 0.05). Serum osteocalcin was lower in the 0.17% Met-Ex group compared with the other 2 exercise groups and the 0.17% Met group (P < 0.05). Serum concentrations of C-terminal telopeptide of type 1 collagen were lower in exercise-trained and 0.17% Met-fed rats than in sedentary rats and rats fed the other 2 diets (P < 0.05 for both). Rats fed the 0.17% Met diet had lower trabecular bone volume, bone mineralization activities, and bone mineral content (BMC; e.g., total, cortical, and spongy BMC) and bone mineral density (BMD; e.g., total and spongy BMD) indices compared with rats fed the other 2 diets (P < 0.05). Exercise-trained rats also had lower bone mineralization activity, trabecular osteoclast density, total BMC, cortical BMC, and total BMD compared with sedentary rats (P < 0.05). In total BMD, only the 0.17% Met-Ex group had values lower than the other 2 exercise groups and the 0.17% Met group (P < 0.05). Compared with rats fed the other 2 diets and sedentary rats, the femora of 0.17% Met-fed and exercise-trained rats, respectively, had smaller size and/or lower extrinsic strength but enhanced intrinsic biomechanical properties (P < 0.05). The results indicate that MR and endurance exercise caused lower whole bone mass, size, and/or strength but might enhance intrinsic bone strength.

Cystathionine γ-Lyase–Hydrogen Sulfide Induces Runt-Related Transcription Factor 2 Sulfhydration, Thereby Increasing Osteoblast Activity to Promote Bone Fracture Healing

“…Restricted feeding with the H2S precursor amino acid methionine caused bone mass loss (13) and reduced RUNX2 expression (32). In this study, we demonstrated that endogenous CSE-H2S has a role in osteoblast differentiation and maturation by inducing RUNX2 sulfhydration, thereby promoting bone healing ( Supplementary Fig.…”

Cysteine dietary supplementation reverses the decrease in mitochondrial ROS production at complex I induced by methionine restriction

“…MetR also attenuates age-dependent increases in both basal insulin and glucose levels in aging rats (Miller et al 2005; Malloy et al (Miller et al 2005;Malloy et al 2006). MetR improves insulin sensitivity and increases resistance to obesity (Ables et al 2012), inhibits cancer growth (Cavuoto and Fenech 2012), decreases systemic inflammation through wide changes in transcription profiles (Wanders et al 2014), increases intrinsic muscle strength (Huang et al 2014), and prevents the progression of hepatic steatosis in obese mice . In addition, MetR lowers oxidative stress.…”

Increased intrinsic stiffness and mineralization in femurs of adult rats after high intensity treadmill running training

“…It is also possible that the mechanostat had not enough time to induce the adaptive modifications at the level of the bone geometrical properties or that they were too small to be measured with our methods. However, others have shown no geometric adaptation of weight-bearing bones in exercise trained rats in spite of increased strength and stiffness [9,12,13,21].…”

“…The time and the degree of the endurance treadmill running training were not uniform in the different studies, although most of them revealed that this type of exercise has effects on bone density, size and shape, resulting in substantial improvements in mechanical strength. However, subnormal values of bone mass, size, and strength were also described in association with enhanced intrinsic bone strength [13] which may represent real benefits in the biomaterial quality of bone [12]. Increased Young's modulus and higher concentration of Ca in femurs of trained rats were also described [9].…”