The prevention effect of pulsed electromagnetic fields treatment on senile osteoporosis in vivo via improving the inflammatory bone microenvironment.

This study aimed to assess PEMF in a rat model of senile osteoporosis and its relationship with NLRP3-mediated low-grade inflammation in the bone marrow microenvironment. A total of 24 Sprague Dawley (SD) rats were included in this study. Sixteen of them were 24-month natural-aged male SD rats, which were randomly distributed into the Aged group and the PEMF group (n = 8 per group). The remaining 8 3-month -old rats were used as the Young positive control group (n = 8). Rats in the PEMF group received 12 weeks of PEMF with 40 min/day, five days per week, while the other rats received placebo PEMF intervention. Bone mineral density/microarchitecture, serum levels of CTX-1 and P1CP, and NLRP3-related signaling genes and proteins in rat bone marrow were then analyzed. The 12-week of PEMF showed significant mitigation of aging-induced bone loss and bone microarchitecture deterioration, i.e. PEMF increased the bone mineral density of the proximal femur and L5 vertebral body and improved parameters of the proximal tibia and L4 vertebral body. Further analysis showed that PEMF reversed aging-induced bone turnover, specifically, decreased serum CTX-1 and elevated serum P1CP. Furthermore, PEMF also dramatically inhibited NLRP3-mediated low-grade inflammation in the bone marrow, i.e. PEMF inhibited the levels of NLRP3, proCaspase1, cleaved Caspase1, IL-1ß, and GSDMD-N. The study demonstrated that PEMF could mitigate the aging-induced bone loss and reverses the deterioration of bone microarchitecture probably through inhibiting NLRP3-mediated low-grade chronic inflammation to improve the inflammatory bone microenvironment in aged rats.

Protective effects of pulsed electromagnetic field therapy attenuates autophagy and apoptosis in osteoporotic osteoarthritis model rats by activating PPARγ.

Osteoporotic osteoarthritis (OPOA) is a specific phenotype of OA with high incidence and severe cartilage damage. This study aimed to explore the protective efficacy of PEMF on the progression of OPOA and observed the effects of PEMF on PPARγ, autophagy- and apoptosis-related proteins in OPOA rats. Rats were randomly divided into three groups: control group, OPOA group, and PEMF group (n = 6). One week after surgery, the rats in PEMF group were subjected to PEMF (3.82 mT, 8 Hz, 40 min/day and 5 day/week) for 12 weeks. Results showed that PEMF retarded cartilage degeneration and bone loss, as evidenced by pathological staining image, decreased MMP-13 expression and increased bone mineral density. PEMF inhibited the serum levels of inflammatory cytokines, and the expressions of caspase-3 and caspase-8, while upregulated the expression of PPARγ. Moreover, PEMF significantly improved the autophagy disorders, represented by decrease expressions of Beclin-1, P62, and LC3B. The research demonstrates that PEMF can effectively prevent cartilage and subchondral bone destruction in OPOA rats. The potential mechanism may be related to upregulation of PPARγ, inhibition of chondrocyte apoptosis and inflammation, and improvement of autophagy disorder. PEMF therapy thus shows promising application prospects in the treatment of postmenopausal OA.

Osteoporotic osteoarthritis (OPOA) is a very common combination disease, that characterized by chronic pain, swollen joints and susceptibility to fractures. It is particularly common in postmenopausal women. At present, drug therapy is the main treatment method, but the adverse reactions are serious and can not stop the progression of the disease. PEMF is a safe physical therapy that has been shown to increase bone density, reduce pain, and improve joints mobility. In this study, we aimed to explore the protective effect and potential mechanism of PEMF on OPOA. We found that PEMF significantly inhibited the inflammatory response, ameliorated the damaged cartilage and subchondral bone in OPOA rats, that maybe related to the regulation of chondrocyte autophagy and apoptosis. This study provided a new vision for PEMF' treatment on OPOA and has positive significance for the clinical promotion of PEMF.

High-frequency repetitive transcranial magnetic stimulation protects against cerebral ischemia/reperfusion injury in rats: Involving the mitigation of ferroptosis and inflammation.

BACKGROUND AND AIM: Repetitive transcranial magnetic stimulation (rTMS) has been found to attenuate cerebral ischemia/reperfusion (I/R) injury. However, its effects and mechanism of action have not yet been clarified. It has been reported that cerebral I/R injury is closely associated not only with ferroptosis but also with inflammation. Hence, the current study aimed to investigate whether high-frequency rTMS attenuates middle cerebral artery occlusion (MCAO)-induced cerebral I/R injury and further to elucidate the mediatory role of ferroptosis and inflammation. METHODS: The protective effects of rTMS on experimental cerebral I/R injury were investigated using transient MCAO model rats. Neurological scores and pathological changes of cerebral ischemic cortex were assessed to evaluate the effects of rTMS on cerebral I/R injury. The involvement of ferroptosis and that of inflammation were examined to investigate the mechanism underlying the effects of rTMS. RESULTS: High-frequency rTMS remarkably rescued the MCAO-induced neurological deficits and morphological damage. rTMS treatment also increased the mRNA and protein expression of glutathione-dependent peroxidase 4, decreased the mRNA and protein levels of acyl-CoA synthetase long-chain family member 4 and transferrin receptor in the cortex. Moreover, rTMS administration reduced the cerebrospinal fluid IL-1ß, IL-6, and TNF-α concentrations. CONCLUSION: These findings implicated that high-frequency rTMS alleviates MCAO-induced cerebral I/R injury, and the underlying mechanism could involve the inhibition of ferroptosis and inflammation. Our study identifies rTMS as a promising therapeutic agent for the treatment of cerebral I/R injury. Moreover, the mechanistic insights into ferroptosis and inflammation advance our understanding of it as a potential therapeutic target for diseases beyond cerebral ischemia stroke.

Treadmill training mitigates bone deterioration via inhibiting NLRP3/Caspase1/IL-1ß signaling in aged rats.

INTRODUCTION: Although aerobic physical exercise may improve osteoporosis during ageing, the underlying mechanism of the favorable effects remains unclear. The aim of this study was to examine the localized and generalized proinflammatory indicators and the adaptive skeletal responses to treadmill training in aged rats to explore the potential mechanisms by which treadmill training impacts bone deterioration in a natural aged rat model. MATERIALS AND METHODS: A total of 24 Sprague Dawley (SD) rats were included in this study. Sixteen of all these animals were twenty-four months natural aged male SD rats, which were distributed into two groups (n = 8/group): AC group with sham treadmill training, and AT group with 8 weeks treadmill training. The remaining 8 were six months male SD rats matched subline and supplier, which were used as the adult control group with sham treadmill training (YC group, n = 8). The serum, bone marrow, fresh femur, tibia, and lumbar spine were harvested for molecular biological analysis, bone mineral density (BMD) testing, and micro-CT analysis after 8 weeks of treadmill training. RESULTS: After 8 weeks of intervention, the results showed that treadmill training increased BMD and inhibited deterioration of bone microarchitecture of hind limb bones. Further analysis showed that treadmill training increased serum P1CP concentration and decreased serum CTX-1level. Interestingly, treadmill training down-regulated the protein expressions of proinflammatory indicators, including NLRP3, proCaspase1, cleaved Caspase1, IL-1ß, and GSDMD-N, and the mRNA levels of NLRP3, Caspase1, and IL-1ß of the bone marrow. In addition, treadmill training also inhibited serum TNF-α and IL-1ß concentration. However, 8 weeks of treadmill training did not increase BMD and bone microarchitecture in the lumbar spine. CONCLUSION: Treadmill training mitigates the ageing-induced bone loss and reverses the deterioration of bone microarchitecture in hind limbs probably through inhibiting NLRP3/Caspase1/IL-1ß signaling to attenuate low-grade inflammation and improve the inflammatory bone microenvironment.

Effect of the Pulsed Electromagnetic Field Treatment in a Rat Model of Senile Osteoporosis In Vivo.

This study assessed the effects of pulsed electromagnetic fields (PEMF) in a rat model of senile osteoporosis and the underlying molecular events. 24-month-old male Sprague-Dawley (SD) rats were randomly divided into control and PEMF groups (n = 8 per group) using a random digit table, while 3-month-old male SD rats were set as the young-age control group. Rats in the PEMF group were treated by PEMF for 40 min/day for 5 days/week. Bone mineral density/microarchitecture, level of serum bone-specific alkaline phosphatase (BALP), tartrate-resistant acid phosphatase 5b (TRACP5b), and Wnt/ß-catenin signaling genes in rat bone marrow cells were then analyzed. The 12-week PEMF intervention showed a significant effect on inhibition of age-induced bone density loss and deterioration of trabecular bone structures in the PEMF group rats versus control rats, that is, the treatment enhanced bone mineral density of the proximal femoral metaphysis and the fifth lumbar (L5) vertebral body and improved the proximal tibia and L4 vertebral body parameters using bone histomorphometry analysis. Furthermore, the BALP level in the bones was significantly increased, but the TRACP5b level was reduced in the PEMF group of rats versus control rats. PEMF also dramatically upregulated expression of Wnt3a, LRP5, ß-catenin, and Runx2 but downregulated PPAR-γ expression in the aged rats. The results demonstrated that PEMF could prevent bone loss and architectural deterioration due to the improvement of bone marrow mesenchymal stromal cell differentiation and proliferation abilities and activating the Wnt signaling pathway. Future clinical studies are needed to validate these findings. © 2022 Bioelectromagnetics Society.

[Effect of electroacupuncture at "Shuigou" (GV26) and "Baihui" (GV20) on autophagy of hippo-campal neurons in rats with cerebral ischemia-reperfusion injury].

OBJECTIVE: To explore the effect of electroacupuncture (EA) at "Shuigou"(GV6) and "Baihui"(GV20) on autophagy of hippocampal neurons in cerebral ischemia-reperfusion (I/R) injury rats. METHODS: Forty-eight healthy male SD rats were randomly divided into sham operation, model and EA groups, with 16 rats in each group. The rat model of cerebral I/R injury was established by occlusion of the middle cerebral artery (MCAO). Rats of the EA group received EA at GV26 and GV20 for 20 min, once daily for 5 days. The neurological function of rats in each group was evaluated by Longa neurological function score. The cerebral infarction volume was measured by TTC staining. The levels of IL-6, IL-18 and TNF-α in cerebrospinal fluid were detected by ELISA. Real-time PCR and Western blot were respectively used to detect the expressions of autophagy-related proteins AMPK, Beclin-1, VPS34 and LC3B. RESULTS: Compared with the sham operation group, neurological function scores of rats in the model group were significantly increased (P<0.01); the volume of cerebral infarction was significantly increased (P<0.01); the contents of IL-6, IL-18 and TNF-α in cerebrospinal fluid were increased (P<0.01, P<0.05); the mRNA expression levels of AMPK, Beclin-1, VPS34 and LC3B were significantly increased (P<0.01); the protein expressions of AMPK, Beclin-1, VPS34 and the ratio of LC3B-Ⅱ/LC3B-Ⅰ were increased (P<0.01, P<0.05). After intervention and in comparison with the model group, the neurological function scores were decreased (P<0.05); the cerebral infarct volume were decreased (P<0.05); the contents of IL-6, IL-18 and TNF-α in cerebrospinal fluid were decreased (P<0.05); the mRNA expressions of AMPK, Beclin-1, VPS34 and LC3B were significantly decreased (P<0.01); the protein expressions of AMPK, Beclin-1, VPS34 and the ratio of LC3B-Ⅱ/LC3B-Ⅰ were decreased (P<0.05, P<0.01). CONCLUSION: EA can improve the neurological function and alleviate the degree of nerve injury in rats with cerebral I/R injury, which may be related to inhibiting the autophagy level of hippocampal neurons.

Pulsed electromagnetic field alleviates synovitis and inhibits the NLRP3/Caspase-1/GSDMD signaling pathway in osteoarthritis rats.

Low-grade inflammation is a key mediator of the pathogenesis of Osteoarthritis (OA). Pulsed electromagnetic field (PEMF) can improve the symptoms of OA and potentially acts as an anti-inflammatory. The aim of this study was to investigate the effect of the PEMF on OA and its relationship with the NLRP3/Caspase-1/GSDMD signaling pathway.18 Three-month-old Sprague-Dawley (SD) rats were randomly divided into three groups (n = 6 per group): 1) OA group, 2) OA+PEMF group (OA with PEMF exposure), 3) Control group (sham operation with placebo PEMF). Rats in the OA and OA+PEMF groups were subjected to bilateral anterior cruciate ligament transection and ovariectomy. PEMF scheme: Pulse waveform, 3.82 mT, 8 Hz, 40 min/day, 5 days a week, for 12 weeks. The expression levels of NLRP3, Caspase-1, GSDMD, IL-1ß, and MMP-13 were detected by qRT-PCR and Western blot. The pathological structures of OA were monitored with Safranin O/fast green staining and hematoxylin eosin staining. Our results showed that PEMF alleviated the degree of inflammation and degeneration of cartilage in rats with OA, based on the histopathological changes and decline of the expression of IL-1ß and MMP-13. Moreover, the over-expression of NLRP3, Caspase-1, and GSDMD in the cartilage of the OA rats decreased after PEMF treatment. These results suggested that PEMF could be a highly promising noninvasive strategy to slow down the progression of OA and inhibition of the NLRP3/Caspase-1/GSDMD signaling pathway might be involved in the beneficial effect of PEMF.

Effects of Ultrashort Wave Therapy on Inflammation and Macrophage Polarization after Acute Lung Injury in Rats.

Acute lung injury (ALI) features dysregulated pulmonary inflammation. Ultrashort waves (USWs) exert anti-inflammatory effects but no studies have evaluated their activity in ALI. Herein, we used an in vivo lipopolysaccharide (LPS)-induced ALI model to investigate whether the anti-inflammatory activity of USWs is mediated by altering the polarization of M1 to M2 macrophages. Twenty-four male Sprague-Dawley rats were randomly divided into control, untreated ALI, and ALI treated with USW groups (n = 8 in each group). ALI was induced by intratracheal LPS instillation. Rats in the USW group were treated for 15 min at 0, 4, and 8 h after a single LPS intratracheal instillation. Histopathologic examination, wet/dry lung weight ratio, enzyme-linked immunosorbent assay, quantitative real-time polymerase chain reaction, and western blot analyses were performed to evaluate the degree of lung injury and to determine macrophage phenotypes. Histopathologic examination disclosed attenuation of ALI, with reduced alveolar hemorrhage and neutrophilic infiltration in the USW group. Serum levels of tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) were significantly decreased after USW therapy. Moreover, the messenger RNA (mRNA) expressions of TNF-α and IL-1ß were significantly decreased in the USW group, whereas the mRNA expression of Arginase 1 (Arg1) and the protein expression of mannose receptor significantly increased in comparison with the untreated ALI group. We conclude that USW therapy may attenuate inflammation in LPS-induced ALI through the modulation of macrophage polarization. © 2021 Bioelectromagnetics Society.