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Summary Supplements and naturally occurring nutraceuticals effective for maintenance or enhancement of skeletal muscle mass are expected to contribute to prevention of decreased mobility and increased risk of developing metabolic diseases. However, information about available food components remains widely unavailable. In the present study, we investigated the effects of dietary b-carotene on the quantity and quality of skeletal muscle under physiological conditions. Male ddY mice (8 wk old) were orally administered b-carotene (0.5 mg once daily) for 14 d. Dietary b-carotene had no influence on body weight, but increased the soleus muscle/body weight ratio. The cross-sectional area (CSA) in muscle fibers of the soleus muscle was increased, indicating that administration of b-carotene induces muscle hypertrophy. In the soleus muscle of the b-carotene-administered mice, twitch force tended to be increased (p50.06) and tetanic force was significantly increased, whereas specific force (force per CSA) remained unchanged. Dietary b-carotene increased the mRNA level of insulin-like growth factor 1 (Igf-1) as its splicing variant Igf-1ea, but had no influence on the liver Igf-1 mRNA level or serum IGF-1 level. b-Carotene promoted protein synthesis in the soleus muscle and reduced levels of ubiquitin conjugates, but had no influence on the mRNA levels of two atrogenes, Atrogin-1 and Murf1. On the other hand, b-carotene had no influence on the processing of the autophagy marker protein light chain 3. These results indicate that in mice, administration of b-carotene increases mass and induces functional hypertrophy in the soleus muscle, perhaps by promoting IGF-1-mediated protein synthesis and by reducing ubiquitin-mediated protein degradation.

Study design: Experimental training model of rats with spinal cord injury (SCI).Setting: Osaka, Japan Objective: To investigate the effect of forced treadmill training by plantar placement (PP), as compared with dorsal placement (DP), of the dorsal paws on the locomotor behaviors of spinal cord-injured rats. Methods: The spinal cord was contusion-injured at the thoracic level. Rats were divided into three groups: forced training involving stepping by PP and DP and non-forced training/assistance (nT). Training began 1 week after injury and was conducted for 4 weeks. Locomotor behaviors were estimated using Basso-Beattie-Bresnahan (BBB) scores, dorsiflexion of the hind paws and footprints of the hind paws. Histological and immunohistochemical examinations of the spinal cord lesions were conducted after 4 weeks of training. Results: The values, respectively, of PP, DP and nT groups at 4 weeks of training were as follows: BBB scores were 15.6 ± 0.8, 7.7 ± 1.3 and 10.3 ± 0.4. The paw dorsiflexion angles were 34.1 ± 5.2, 16.4 ± 2.4 and 23.6 ± 3.0 degrees, respectively. The stride angles were 5.1 ± 0.9, 13.7 ± 4.9 and 17.8 ± 4.0 degrees for the left paws. Cavity volumes were 10.3 ± 2.1, 31.0 ± 2.0 and 28.2 ± 4.9%. In addition to cavities, there were astrocyte-devoid areas containing some loose tissues, through which many axons extended longitudinally. Conclusions: The BBB score, dorsiflexion angle and stride angle were consistently improved in the PP group. Cavity formation was more reduced, and many axons extended through coarse tissues formed in astrocyte-devoid areas at the lesion in the PP group. INTRODUCTIONSpinal cord injury (SCI) is devastating; patients with SCI lose functions below the level of the injury, and recovery of the locomotor functions is limited even with extensive rehabilitation. Body weight support treadmill (BWST) training with plantar stepping is widely used for locomotor exercises in the rehabilitation of patients with SCI. However, the effectiveness of plantar stepping of the hind feet has not been fully evaluated experimentally. The present study focused on the effect of forced treadmill training by plantar placement (PP) of the hind paws on the locomotor behaviors of rats with SCI. Recent cell transplantation studies have reported the recovery of injured spinal cord tissue and the behavioral improvement of SCI animals. 1 Our previous studies showed that bone marrow stromal cell transplantation is effective for locomotor recovery from SCI in rats, 2 findings that have been applied to clinical cases. 3 Along with the emergence of potentially effective treatments of SCI, including cell transplantation therapy, hope for the rehabilitation of patients with SCI has increased. It is now all the more important to experimentally explore the effects of rehabilitation on recovery from SCI.

Study design: Experimental, controlled study. Objective: To examine the effects of whole-body vibration (WBV) on bone mass and trabecular bone microstructure (TBMS) during the early stage in juvenile rats with spinal cord injury (SCI). Setting: Studied at the Kio University in Japan. Methods: Thirty-four 8-week-old male Wistar rats were divided into 3 groups: the SCI group, the sham-operation group (SHAM) and the SCI+WBV group. WBV started on the 8th day after SCI. After 1 or 2 weeks of WBV treatment, measurements of tissue mineral density, trabecular bone mineral content (BMC) and parameters of TBMS were obtained by scanning the proximal tibias with x-ray micro-computed tomography. Serum levels of osteocalcin (OC) and of tartrate-resistant acid phosphatase 5b (TRACP 5b) were measured with ELISA. Results: BMC, volume bone mineral density, bone volume (BV), BV fraction (BV/tissue volume) and connectivity density (Conn.D) of TBMS parameters were significantly higher in SCI+WBV rats than in SCI rats after 2-week WBV. The BMC and BV/TV of bone mass index correlated well with Conn.D, suggesting the preservation of Conn.D. induced by WBV. SCI+WBV rats showed a decrease in serum OC after 1-week WBV, but a quick recovery from that after 2-week WBV. There was no difference in serum TRACP 5b among the 3 groups throughout the experimental period. Conclusion: WBV treatment could attenuate the bone deterioration that occurs during the early stage in juvenile rats with SCI. In a clinic, this early WBV intervention may be an effective rehabilitation modality for preventing bone fragility in SCI patients. Spinal Cord (2016) 54, 597-603; doi:10.1038/sc.2015.220; published online 22 December 2015 INTRODUCTION Osteoporosis is a well-known complication of spinal cord injury (SCI).The mechanism of bone loss by SCI is complex and is constituted by multiple factors involving mechanical, neurovascular, hormonal and metabolic factors. 1,2 Bone loss following SCI begins within the first 6 months after the injury, and stabilizes between 12 and 16 months. 3 Bone loss is especially prominent in sublesional bones such as the distal femur and proximal tibia. [4][5][6][7][8] In fact, bone mass in the distal femur and proximal tibia decreased by 51% and 70%, respectively, within 1 year after the injury in SCI patients. 6 These two bones were so fragile that even a weak physical impact could cause a fracture in SCI patients. 7,8 Therefore, the frequency of fracture in SCI patients was about twice as high as that of healthy people. 9 Edwards et al. 10 showed that in the femur and tibia of acute SCI patients trabecular bone mineral content (BMC) was reduced by 3.1-4.4% per month and volumetric bone mineral density (BMD) by 2.7-4.7% per month within 4 months after the injury. In addition, cortical BMC and volumetric BMD were noticeably reduced, and furthermore bone strength indices were decreased. 10 The incidence of SCI is higher in young people aged 15-24 years. 11 Children (aged 5-13 years) with

Age-related changes of physiological and biochemical properties were examined in the diaphragm muscle, which has particularly high activation compared to that of other skeletal muscles. The diaphragm from 10-week-, 50-week-and 100-week-old male Wistar rats were used to measure in vitro isometric contractile properties, sarcoplasmic reticulum (SR) Ca 2+ -ATPase activity, and myosin heavy chain (MHC) isoform composition. Although there were no significant differences in specific twitch tension of the diaphragm among the groups, there was significant reduction in specific tetanic tension in the 50-week to 100-week groups. The contraction time and 1/2 relaxation time of twitch contraction extended with aging, and significant differences were found between 10-week-old and 100-week-old diaphragms. Regarding the activity of SR Ca 2+ -ATPase, the pattern of age-related change was similar to that in the 1/2 relaxation time and there was a significant difference between 10-week-old and 100-week-old diaphragms. There was a significant increase in the relative composition of the MHC I isoform in 100-week-diaphragms compared to that in 10-week-old diaphragms and a concomitant decrease in the relative composition of fast myosin was noted. These findings demonstrated that older diaphragms have slower contraction and relaxation speeds, and these alterations were attributed to changes in SR Ca 2+ -ATPase activity and MHC isoform composition.Common age-related changes in physical functions include decreases in balance, visual acuity and hearing. With regard to skeletal muscles, changes such as muscle mass loss (18), lower muscle tension (9, 15), selective atrophy of fast-twitch fibers (16), and reduced mitochondrial enzyme and glycolytic enzyme activities (6) have been reported. These agerelated changes may cause falls, fractures and bed confinement, which are important social problems. Age-related changes in skeletal muscles have also been reported to affect not only the muscle fibers themselves, but also the oxygen supply to the cardiovascular system (22) and a decline in the number of spinal cord axons and nerve conduction velocity involved in contraction. Suppressing such age-related changes is considered important for successful aging. In rehabilitation, the diaphragm plays a wide variety of roles, including respiratory rehabilitation before and after surgery, home oxygen therapy for chronic obstructive pulmonary disease and cardiorespiratory responses in sports. Many rehabilitation therapists select abdominal breathing (diaphragmatic respiration) as the first-choice respiratory muscle exercise in acute and chronic patients. The diaphragm is the main action muscle of diaphragmatic respiration, and is always active in life maintenance; thus, when compared with other skeletal muscles, the diaphragm is more active. Hence, investigating chrono-