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BACKGROUND:Exercise training can improve osteoporosis,but its effects and mechanisms on senile osteoporosis are not fully understood. OBJECTIVE:To observe the effect of treadmill exercise on osteoporosis and wnt/β-catenin signal pathway in aged rats. METHODS:Sixteen 24-month-old male Sprague-Dawley rats were randomly divided into osteoporosis group(n=8)and treadmill group(n=8)and eight 6-month-old male Sprague-Dawley rats were used as young control group.The model of senile osteoporosis was replicated by natural aging and the rats in the treadmill group were treated with treadmill exercise once a day,5 days a week,for 8 weeks.Levels of bone metabolic markers such as type I collagen cross-linked C-terminal peptide,tartrate resistant acid phosphatase,osteocalcin and bone specific alkaline phosphatase were detected by ELISA;bone mineral density of the left femur and L5 was measured by dual energy X-ray;bone scanning and bone microstructure quantitative analysis were performed by bone micro-CT;and the mRNA and protein expression levels of wnt3a,β-catenin,LRP5,DKK1 and GSK3β were detected by RT-PCR and western blot,respectively. RESULTS AND CONCLUSION:Compared with the young control group,the osteoporosis group showed a reduction in serum bone specific alkaline phosphatase and osteocalcin levels(P<0.05),bone mineral density of the femur and L5,the number of tibia and L4 bone trabeculae,bone volume,bone volume fraction(P<0.05),and mRNA and protein expression of wnt3a,β-catenin,and LRP5 in bone marrow tissue(P<0.05)as well as an increase in serum levels of tartrate resistant acid phosphatase and type I collagen cross-linked C-terminal peptide(P<0.05),the intertrabecular space between the tibia and L4,structural model index(P<0.05),and mRNA and protein expression of DKK1 and GSK3 β in bone marrow tissue(P<0.05).In addition to the reduced number of trabeculae in the tibia and L4 vertebrae,the trabeculae were structurally disturbed and sparsely aligned and fractured.Compared with the osteoporosis group,the treadmill group showed an increase in serum bone specific alkaline phosphatase and osteocalcin levels(P<0.05),bone mineral density of the femur and L5(P<0.05),the number of tibial trabeculae,bone volume,bone volume fraction(P<0.05),mRNA and protein expression of wnt3a,β-catenin,and LRP5 in bone marrow tissue(P<0.05)but a reduction in the serum levels of tartrate resistant acid phosphatase and type I collagen cross-linked C-terminal peptide,L4 trabecular space,tibial trabecular space,structural model index,and mRNA and protein expression of DKK1 and GSK3 β in bone marrow tissue(P<0.05).In addition to the increased number of tibial and L4 trabeculae,the trabeculae were arranged in a regular and dense pattern and were connected to a network.To conclude,treadmill exercise may improve osteoporosis in aged rats by activating the wnt/β-catenin signal pathway.
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BACKGROUND:There are many treatment methods for knee osteoarthritis,among which electroacupuncture,as an important non-drug treatment,is effective in the treatment of knee osteoarthritis,but its exact mechanism is not clear. OBJECTIVE:Effect of electroacupuncture on the expression of p53 and P21 in articular cartilage and subchondral bone of aged rats with knee osteoarthritis. METHODS:Eight 6-month-old male Sprague-Dawley rats were included in the young group and sixteen 24-month-old male Sprague-Dawley rats were randomly divided into old group(n=8)and electroacupuncture group(n=8).The rats in the electroacupuncture group received electroacupuncture stimulation once a day,5 days a week,for 8 continuous weeks,and the other two groups did not do any treatment.Eight weeks later,the level of type Ⅱ collagen C-terminal peptide in peripheral blood was detected by ELISA,the morphology of left knee cartilage and subchondral bone was observed by safranin O-fast green staining,the degree of knee cartilage degeneration was evaluated by modified Mankin's score,the microstructure of left knee cartilage and subchondral bone was detected by micro-CT,and the expression levels of matrix metalloproteinase 13,P53,P21 Mrna and protein were detected by RT-PCR and western blot respectively. RESULTS AND CONCLUSION:Compared with the young group,the level of C-terminal peptide of type Ⅱ collagen in the peripheral blood was increased in the old group(P<0.05).The micro-CT results showed that the bone volume fraction,bone mineral density and the number of bone trabeculae were decreased in the old group compared with the young group(P<0.05),while the trabecular separation increased(P<0.05).Safranin O-fast green staining showed that in the old group,the surface layer of cartilage was uneven with fissures,the morphology of chondrocytes was irregular and stained unevenly,the boundary between the cartilage and subchondral bone was blurred,and the matrix loss was serious.The Mankin's score was higher in the old group than the young group(P<0.05).The expression of matrix metalloproteinase 13,P53,P21 at Mrna and protein levels increased in the old group compared with the young group(P<0.05).Compared with the old group,electroacupuncture decreased the level of C-terminal peptide of type Ⅱ collagen(P<0.05),increased the bone volume fraction,bone mineral density and the number of bone trabeculae(P<0.05),and decreased the trabecular separation(P<0.05).Safranin O-fast green staining showed that in the electroacupuncture group,the surface of cartilage was smooth and red staining was uniform,and the cell morphology and structure were between the young group and the old group.Following electroacupuncture treatment,the Mankin's score(P<0.05),matrix metalloproteinase 13 and P21 Mrna expression(P<0.05),and matrix metalloproteinase 13 and P53 protein expression decreased(P<0.05),while there was a decreasing trend of P53 Mrna and P21 protein expression,but with no statistical significance(P>0.05).To conclude,electroacupuncture may delay articular cartilage degeneration and subchondral osteoporosis in aged rats by inhibiting the expression of P53 and P21,so as to protect joints and delay joint aging.
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BACKGROUND:Inflammation is one of the important factors that induce cerebral ischemia-reperfusion injury.Studies have shown that electroacupuncture can effectively reduce inflammation after ischemic stroke and improve the symptoms of neurological deficits,but the mechanism is not clear. OBJECTIVE:To observe the effect of electroacupuncture on Toll-like receptor 4/nuclear factor-κB in rats with cerebral ischemia-reperfusion injury. METHODS:Forty-eight male Sprague-Dawley rats were randomly divided into sham operation group,model group and electroacupuncture group,with 16 rats in each group.The rat model of cerebral ischemia-reperfusion injury was prepared by middle cerebral artery occlusion.At 24 hours after modeling,the rats in the electroacupuncture group were treated with electroacupuncture,once a day,20 minutes each time,for a total of 5 days.The sham operation group and the model group did not do any intervention.After 5 days of intervention,Longa method was used to evaluate the degree of neurological injury in rats.Triphenyl tetrazolium chloride staining and hematoxylin-eosin staining were used to measure the volume of cerebral infarction and the pathological changes of brain tissue in rats.Serum interleukin-6,interleukin-18 and tumor necrosis factor-α were detected by ELISA.Expressions of Toll-like receptor 4 and nuclear factor-κB in the cerebral cortex at mRNA and protein levels were detected by fluorescence quantitative PCR and western blot,respectively. RESULTS AND CONCLUSION:Compared with the sham operation group,the neurological function scores,serum interleukin-6,interleukin-18,and tumor necrosis factor-α levels,Toll-like receptor 4 and nuclear factor-κB mRNA and protein expression levels were significantly higher in the model group(P＜0.01).Compared with the model group,electroacupuncture significantly reduced the neurological function scores,serum interleukin-6,interleukin-18,and tumor necrosis factor-α levels,Toll-like receptor 4 and nuclear factor-κB mRNA and protein expression levels(P＜0.05,P＜0.01).Compared with the sham operation group,the volume of cerebral infarction in the model group increased significantly(P＜0.01).Compared with the model group,the volume of cerebral infarction in the electroacupuncture group decreased(P＜0.05).In the model group,the arrangement of neurons was disordered,some nerve cells disappeared,nuclei presented with pyknosis and incomplete structure.After electroacupuncture intervention,the degree of neuronal degeneration and neuronal loss in the cerebral cortex of rats were reduced compared with those in the model group.To conclude,electroacupuncture can significantly improve the neurobehavior of rats with cerebral ischemia-reperfusion injury,reduce brain tissue injury,and effectively reduce the level of serum inflammatory factors.The mechanism may be related to the inhibition of Toll-like receptor 4/nuclear factor-κB signaling pathway.
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BACKGROUND:Pulsed electromagnetic fields,as an important physical therapy,are exactly effective in the treatment of osteoarthritis,but the mechanism has not been fully clarified. OBJECTIVE:To observe the effect of pulsed electromagnetic field on the degeneration of knee joint cartilage in aged rats. METHODS:Eight 6-month-old Sprague-Dawley rats were selected as the young group and were subjected to normal diet with no treatment.Sixteen 22-month-old Sprague-Dawley rats were randomly divided into old group(n=8)and pulsed electromagnetic field group(n=8).The rats in the pulsed electromagnetic field group were subjected to a pulsed electromagnetic field intervention,once a day,5 days per week for continuous 8 weeks.The rats in the old group were given no treatment.All rats were anesthetized and executed after 8 weeks for the detection of relevant indexes. RESULTS AND CONCLUSION:Compared with the young group,serum type Ⅱ collagen C-terminal peptide level was increased in the old group(P<0.05);compared with the old group,serum type Ⅱ collagen C-terminal peptide level was decreased in the pulsed electromagnetic field group(P<0.05).Micro-CT showed that the bone volume fraction,bone mineral density,and number of bone trabeculae decreased(P<0.05)and the trabecular separation increased(P<0.05)in the tibia of rats in the aged group compared with the young group;and the bone volume fraction,bone density,and number of trabeculae increased(P<0.05)and the trabecular separation decreased(P<0.05)in the tibia of rats in the pulsed electromagnetic field group compared with the aged group.The tibial plateau Safranin O-fast green staining showed that the articular cartilage structure of rats in the aged group was disorganized,and the number of chondrocytes was obviously reduced,and the tidal line could not be distinguished.The above results were improved in the pulsed electromagnetic field group.RT-qPCR and western blot assay showed that the mRNA and protein expression levels of matrix metalloproteinase 1,matrix metalloproteinase 13,P53 and P21 in the articular cartilage and subchondral bone of rats were elevated in the aged group compared with the young group(P<0.05)and decreased in the pulsed electromagnetic field group compared with the old group(P<0.05).To conclude,pulsed electromagnetic fields may improve osteoarthritis in aged rats by inhibiting chondrocyte senescence,alleviating articular cartilage degradation and inhibiting subchondral bone osteoporosis through suppressing the expression of P53/P21.