Liang Tang

Osteoporosis and hyperglycemia are increasingly recognized as dual public health concerns in T1DM. However, the precise molecular mechanisms by which exercise ameliorates these conditions, particularly the contribution of mechanosensitive channels such as Piezo1, remain incompletely elucidated. To explore these mechanisms, T1DM mice were subjected to a 6-week treadmill training protocol (15 m/min, 20 min/day, 6 days/week) to evaluate the functions of exercise on diabetic osteoporosis and hyperglycemia. Exercise intervention markedly improved bone quality in T1DM mice, alleviating osteoporotic manifestations, as evidenced by enhanced mechanical strength, restored bone microarchitecture, and normalized histomorphology. Concurrently, exercise significantly reduced hyperglycemia. To clarify the role of Piezo1, mechanical stretch was applied to Piezo1-knockout MC3T3-E1 (Piezo1^−/−) cells in vitro, mimicking the mechanical stimulation induced by exercise. Consistent with the in vivo results, mechanical stimulation facilitated osteogenic differentiation and glucose metabolism through Piezo1-mediated mechanotransduction. Importantly, these beneficial effects were substantially abrogated in Piezo1^−/− cells, highlighting the central role of Piezo1. Collectively, these findings demonstrate that Piezo1-mediated mechanotransduction constitutes a critical factor by which exercise mitigates osteoporosis and hyperglycemia in T1DM mice. This study provides a framework for the development of new therapeutic strategies targeting Piezo1-mediated mechanotransduction for T1DM management.

Osteoporosis is highly prevalent in postmenopausal women, causing chronic pain, fractures, and limited mobility that burden individuals and society. While resistance exercise benefits bone health, its role in osteoporotic bone injury healing and underlying mechanisms remain unclear. This study aimed to explore the effects of 10-week weight-bearing ladder climbing exercise on ovariectomy (OVX)-induced osteoporosis and subsequent bone injury healing, and to investigate whether these effects are associated with the myostatin (MSTN) and Wnt/β-catenin pathways. Fifty-four 12-week-old female SD rats were randomized into Sham, OVX, and OVX + EX groups. Rats in the OVX and OVX + EX groups underwent ovariectomy to induce postmenopausal osteoporosis, and those in the OVX + EX group received 10-week weight-bearing ladder climbing. After the exercise intervention, 6 rats in each group were sacrificed; the remaining rats underwent femoral midshaft drilling to establish bone injury. The improvement in osteoporosis was evaluated via Micro-CT, biomechanical tests, RT-qPCR for mRNA detection, and Western blot for measuring protein levels of MSTN and Wnt/β-catenin pathway-related molecules at post-exercise and 21 days post-injury. Bone healing was reflected by the bone volume fraction at the bone injury site detected via Micro-CT at 10 and 21 days post-injury. This exercise significantly enhanced muscle strength and improved femoral bone mineral density (BMD), trabecular microstructure, and biomechanical properties in OVX rats. Meanwhile, the level of MSTN in the OVX + EX group was decreased, the expression of its downstream signaling pathways was inhibited, and the mRNA and protein expressions of Wnt/β-catenin were upregulated. Moreover, 21 days after exercise intervention, the biomechanical properties and bone microstructure of the OVX + EX group were still significantly superior to those of the OVX group, and the aforementioned molecular regulatory effect remained. In addition, pre-conducted exercise was able to promote increases in bone volume fraction at the bone injury site 10 and 21 days after drilling, which was conducive to bone injury healing. Ten-week weight-bearing ladder climbing ameliorates OVX-induced bone loss and promotes osteoporotic bone repair via regulating the MSTN/ActRIIB/Smad3 and Wnt/β-catenin pathways, providing evidence for exercise as a safe non-pharmacological intervention.

Study investigated if abdominal low-intensity pulsed ultrasound (LIPUS) alleviates simulated microgravity (hindlimb unloading, HU)-induced skeletal muscle atrophy by restoring gut microbiota. Mice were divided into control (NC), HU, and HU with daily abdominal LIPUS (HU + LIPUS) groups. Fecal microbiota transplantation (FMT) from LIPUS-treated mice to HU mice was also performed. After 28 days, abdominal LIPUS partially reversed HU-induced gut dysbiosis, restored intestinal barrier integrity, and increased short-chain fatty acid (SCFAs) levels. LIPUS downregulated muscle atrophy genes (MSTN, ActRIIB) and upregulated growth genes (Akt, mTOR) in HU mice, preventing muscle loss. SCFAs levels positively correlated with muscle function. HU mice receiving FMT from LIPUS-treated donors showed similar gut and muscle improvements as direct LIPUS treatment. Results demonstrate abdominal LIPUS ameliorates muscle atrophy by modulating the gut-muscle axis, offering a potential non-invasive strategy for astronauts and patients.

Diabetic skeletal muscle atrophy is one of the most serious complications among diabetes-related complications. LIPUS enhances muscle regeneration and repair in skeletal muscle injuries. However, whether LIPUS can improve skeletal muscle atrophy in mice with T1DM has not been studied. This study involves forty male C57BL/6 mice randomly divided into four groups: normal control group (NC), streptozocin (STZ)-induced T1DM mice (T1D), T1DM mice treated with LIPUS (DL), and T1DM mice treated with insulin (DI). The DL group was treated on the quadriceps of mice with LIPUS (1 MHz, 80 mW/cm², 20 min/day) for 6 weeks. The results demonstrated that LIPUS significantly improved muscle function by increasing the cross-sectional area, mass, and strength of skeletal muscles. In addition, LIPUS significantly effectively lowered the blood glucose levels of T1DM mice. The knockout of myostatin (MSTN) (MSTN^−/−) and knockin of MSTN (MSTN^+/+) mice were employed to verify the underlying mechanism. The results indicated that LIPUS reduces blood glucose levels in T1DM mice by improving their muscle atrophy. This study demonstrated that LIPUS will become a novel therapy for the treatment of skeletal muscle atrophy caused by T1DM.

Weightlessness usually causes disruption of the gut microbiota and impairs cognitive function. There is a close connection between gut microbiota and neuro

Long-term exposure to microgravity leads to muscle atrophy, which is primarily characterized by a loss of muscle mass and strength and reduces one′s functional capability. A weightlessness-induced muscle atrophy model was established using the tail suspension test to evaluate the intervention or therapeutic effect of low-intensity pulsed ultrasound (LIPUS) on muscle atrophy. The rats were divided into five groups at random: the model group (B), the normal control group (NC), the sham-ultrasound control group (SUC), the LIPUS of 50 mW/cm² radiation group (50 UR), and the LIPUS of 150 mW/cm² radiation group (150 UR). Body weight, gastrocnemius weight, muscle force, and B-ultrasound images were used to evaluate muscle atrophy status. Results showed that the body weight, gastrocnemius weight, and image entropy of the tail suspension group were significantly lower than those of the control group (p < 0.01), confirming the presence of muscle atrophy. Although the results show that the muscle force and two weights of the rats stimulated by LIPUS are still much smaller than those of the NC group, they are significantly different from those of the pure tail suspension B group (p < 0.01). On day 14, the gastrocnemius forces of the rats exposed to 50 mW/cm² and 150 mW/cm² LIPUS were 150% and 165% of those in the B group. The gastrocnemius weights were both 135% of those in the B group. This suggests that ultrasound can, to a certain extent, prevent muscular atrophy.

Low-intensity pulsed ultrasound (LIPUS) has been proved to promote the proliferation of myoblast C2C12. However, whether LIPUS can effectively prevent muscle atrophy has not been clarified, and if so, what is the possible mechanism. The aim of this study is to evaluate the effects of LIPUS on muscle atrophy in hindlimb unloading rats, and explore the mechanisms. The rats were randomly divided into four groups: normal control group (NC), hindlimb unloading group (UL), hindlimb unloading plus 30 mW/cm² LIPUS irradiation group (UL + 30 mW/cm²), hindlimb unloading plus 80 mW/cm² LIPUS irradiation group (UL + 80 mW/cm²). The tails of rats in hindlimb unloading group were suspended for 28 days. The rats in the LIPUS treated group were simultaneously irradiated with LIPUS on gastrocnemius muscle in both lower legs at the sound intensity of 30 mW/cm² or 80 mW/cm² for 20 min/d for 28 days. C2C12 cells were exposed to LIPUS at 30 or 80 mW/cm² for 5 days. The results showed that LIPUS significantly promoted the proliferation and differentiation of myoblast C2C12, and prevented the decrease of cross-sectional area of muscle fiber and gastrocnemius mass in hindlimb unloading rats. LIPUS also significantly down regulated the expression of MSTN and its receptors ActRIIB, and up-regulated the expression of Akt and mTOR in gastrocnemius muscle of hindlimb unloading rats. In addition, three metabolic pathways (phenylalanine, tyrosine and tryptophan biosynthesis; alanine, aspartate and glutamate metabolism; glycine, serine and threonine metabolism) were selected as important metabolic pathways for hindlimb unloading effect. However, LIPUS promoted the stability of alanine, aspartate and glutamate metabolism pathway. These results suggest that the key mechanism of LIPUS in preventing muscle atrophy induced by hindlimb unloading may be related to promoting protein synthesis through MSTN/Akt/mTOR signaling pathway and stabilizing alanine, aspartate and glutamate metabolism.