Objective To investigate the effect of dexmedetomidine(Dex)on bone loss in tail-suspended rats and primarily explore its regulatory mechanism on bone metabolism.Methods A total of 30 male rats were randomly divided into a control group,a model group,and a Dex group,with 10 animals in each group.Rat model of osteoporosis was established by hind limb suspension for 4 weeks.Dex at a dose of 10 μg/kg was given intraperitoneally,once every other day from the day of tail suspension.And equal amount of normal saline was given to the control and model group.Bone histological staining was used to observe the trabecular bone area fraction.Biomechanical three-point bending test was employed to measure the maximum load,stiffness,and fracture energy.Dual calcein/alizarin red fluorescence labeling and tartrate resistant acid phosphatase(TRAP)staining were applied respectively to detect the mineral apposition rate and bone formation rate as well as the number of osteoclasts on bone surfaces.Secondly,after primary osteoblasts were isolated from the tibiae of tail-suspended rats and then treated with 1 nmol/L Dex,the proportion of alkaline phosphatase(ALP)-positive osteoblasts and the activity of the enzyme were detected by ALP staining and activity test.qRT-PCR was applied to measure the expression of osteogenic activity-related factors,including osteocalcin(Ocn),Runt related transcription factor 2(Runx2),Osterix protein(Osx),and type 1 collagen(Col1).Results The animal experiments revealed that Dex treatment significantly increased the tibial trabecular bone area fraction,inhibited the decrease in bone mechanical strength,and enhanced the mineralization deposition rate and new bone formation rate of trabecular bone in the tail-suspended rats(all P＜0.001).The in vitro experiments showed that Dex treatment obviously improved ALP activity and the number of ALP-positive osteoblasts in primary osteoblasts isolated from tail-suspended rats(P＜0.01),and up-regulated the expression levels of osteogenic differentiation-related genes,such as Ocn,Runx2,Osx and Col1(P＜0.01).Conclusion Dex exerts anti-bone loss effect in tail-suspended rats,which may be associated with its stimulation on osteoblast-mediated bone formation.

Objective:To investigate the effects of pulsed electromagnetic field(PEMF)on sevoflurane-induced cognitive dysfunction in elderly rats and also explore its related mechanism.Methods:Thirty elderly male rats were randomly divided into the control group,sevoflurane treatment group(SEV),and sevoflurane+PEMF treatment group(SEV+PEMF).Rats in the sevoflurane group and sevoflurane+PEMF group passively inhaled 2.5％sevoflurane for 4 h,while rats in the SEV+PEMF group were stimulated with 2 mT,15 Hz PEMF for 14 d(2 h/day).The cognitive function of rats was evaluated via the Morris water maze testing.The serum concentrations of tumor necrosis factor-α(TNF-α),interleukin-1 β(IL-1β),IL-6,neuron specific enolase(NSE),and β amyloid protein(Aβ),as well as the levels of nerve growth factor(NGF)and brain-derived neurotrophic factor(BDNF)in hippocampal tissue,were de-termined via ELISA.Western blot was used to detect the expression of autophagy-related biomarkers in rat hippocampal tissue.Secondly,30 elderly male rats were randomly divided into three groups:SEV group,SEV+PEMF group,and SEV+3-MA(the autophagy inhibitor)+PEMF group.The Morris water maze experiment was used to evaluate the change of PEMF-induced improvement of cognitive function sevoflurane-inhaled elderly rats following the autophagy inhi-bition.Results:PEMF inhibited sevoflurane-induced increase in escape latency and overall swimming distance,as well as the decrease in the number of crossing target quadrant(P＜0.05);PEMF decreased the levels of serum Aβ and NSE in elderly rats inhaled with sevoflurane(P＜0.05),decreased the levels of TNF-α,IL-1β,and IL-6(P＜0.05),increased the levels of NGF and BDNF in hippocampal tissue(P＜0.05),inhibited neuronal apoptosis in hip-pocampal tissue and increased its autophagy level(P＜0.05).Following inhibition of autophagy with 3-MA,the im-provement of PEMF on the decreased learning and memory ability induced by sevoflurane in elderly rats was significantly inhibited(P＜0.05).Conclusion:PEMF can effectively inhibit sevoflurane-induced cognitive dysfunction in elderly rats by regulating the autophagy of hippocampal neuronal cells.

BACKGROUND:With the increasing demand for orthopedic implants,the search for materials with good biocompatibility and degradability has become a research hotspot.Magnesium-lithium-gadolinium(Mg-Li-Gd)alloy has good degradability,biocompatibility,and mechanical properties,providing ideal supporting conditions for fracture healing.OBJECTIVE:To evaluate the effects of Mg-Li-Gd alloy implants on bone healing in rats.METHODS:A circular half-defect model was made on the lateral side of the right mid-femoral segment in 28 SD rats,and the rats were randomly divided into two groups.The stainless steel group was fixed with a stainless steel intramedullary nail,and the magnesium alloy group was fixed with an Mg-Li-Gd alloy intramedullary nail,with 14 rats in each group.At 2,8,and 14 weeks after surgery,right femur X-ray and Micro-CT examinations,as well as hematoxylin-eosin staining,immunohistochemical staining,and western blot assay were performed.RESULTS AND CONCLUSION:(1)X-ray film:At 2 weeks after surgery,the osteotomy lines of both groups were clear,the density of the intramedullary nail in the magnesium alloy group was close to that of bone tissue,and the density of the intramedullary nail in the stainless steel group was higher than that of bone tissue.At 8 weeks after surgery,the osteotomy lines of both groups were blurred,and the intramedullary nail in the magnesium alloy group had corroded and degraded.At 14 weeks after surgery,the osteotomy lines of both groups disappeared,and the intramedullary nail in the magnesium alloy group further corroded and degraded.(2)Micro-CT:At 2 weeks after surgery,callus began to form in both groups;8 weeks after surgery,the stainless steel group entered the callus remodeling stage,and a relatively dense bone structure was formed at the bone defect site,and the magnesium alloy group showed obvious callus hyperplasia at the bone defect site.At 14 weeks after surgery,the stainless steel group showed a mature bone remodeling process,and thick cortical bone was formed at the bone defect site,and thinner cortical bone was formed in the magnesium alloy group.(3)Hematoxylin-eosin staining:At 2 weeks after surgery,a large number of osteoblasts,osteocytes,a small number of osteoclasts and trabecular structures were observed in the magnesium alloy group,while relatively few osteoblasts and osteocytes were observed in the stainless steel group.At 8 weeks after surgery,a large number of osteoblasts,osteocytes,and mature trabecular structures were observed in the magnesium alloy group,while a large number of osteocytes and lamellar bones were observed in the stainless steel group.At 14 weeks after surgery,lamellar bones were observed in the magnesium alloy group,while mature bone tissue was observed in the stainless steel group.(4)Immunohistochemical staining and western blot assay:At the same time point,the expression levels of bone morphogenetic protein 2,osteocalcin,and RUNX2 proteins in the magnesium alloy group were higher than those in the stainless steel group.(5)The results showed that compared with stainless steel materials,Mg-Li-Gd alloy had no obvious advantage in promoting the formation of fracture healing structure.

BACKGROUND:With the increasing demand for orthopedic implants,the search for materials with good biocompatibility and degradability has become a research hotspot.Magnesium-lithium-gadolinium(Mg-Li-Gd)alloy has good degradability,biocompatibility,and mechanical properties,providing ideal supporting conditions for fracture healing.OBJECTIVE:To evaluate the effects of Mg-Li-Gd alloy implants on bone healing in rats.METHODS:A circular half-defect model was made on the lateral side of the right mid-femoral segment in 28 SD rats,and the rats were randomly divided into two groups.The stainless steel group was fixed with a stainless steel intramedullary nail,and the magnesium alloy group was fixed with an Mg-Li-Gd alloy intramedullary nail,with 14 rats in each group.At 2,8,and 14 weeks after surgery,right femur X-ray and Micro-CT examinations,as well as hematoxylin-eosin staining,immunohistochemical staining,and western blot assay were performed.RESULTS AND CONCLUSION:(1)X-ray film:At 2 weeks after surgery,the osteotomy lines of both groups were clear,the density of the intramedullary nail in the magnesium alloy group was close to that of bone tissue,and the density of the intramedullary nail in the stainless steel group was higher than that of bone tissue.At 8 weeks after surgery,the osteotomy lines of both groups were blurred,and the intramedullary nail in the magnesium alloy group had corroded and degraded.At 14 weeks after surgery,the osteotomy lines of both groups disappeared,and the intramedullary nail in the magnesium alloy group further corroded and degraded.(2)Micro-CT:At 2 weeks after surgery,callus began to form in both groups;8 weeks after surgery,the stainless steel group entered the callus remodeling stage,and a relatively dense bone structure was formed at the bone defect site,and the magnesium alloy group showed obvious callus hyperplasia at the bone defect site.At 14 weeks after surgery,the stainless steel group showed a mature bone remodeling process,and thick cortical bone was formed at the bone defect site,and thinner cortical bone was formed in the magnesium alloy group.(3)Hematoxylin-eosin staining:At 2 weeks after surgery,a large number of osteoblasts,osteocytes,a small number of osteoclasts and trabecular structures were observed in the magnesium alloy group,while relatively few osteoblasts and osteocytes were observed in the stainless steel group.At 8 weeks after surgery,a large number of osteoblasts,osteocytes,and mature trabecular structures were observed in the magnesium alloy group,while a large number of osteocytes and lamellar bones were observed in the stainless steel group.At 14 weeks after surgery,lamellar bones were observed in the magnesium alloy group,while mature bone tissue was observed in the stainless steel group.(4)Immunohistochemical staining and western blot assay:At the same time point,the expression levels of bone morphogenetic protein 2,osteocalcin,and RUNX2 proteins in the magnesium alloy group were higher than those in the stainless steel group.(5)The results showed that compared with stainless steel materials,Mg-Li-Gd alloy had no obvious advantage in promoting the formation of fracture healing structure.

Objective:To investigate the effects of pulsed electromagnetic field(PEMF)on sevoflurane-induced cognitive dysfunction in elderly rats and also explore its related mechanism.Methods:Thirty elderly male rats were randomly divided into the control group,sevoflurane treatment group(SEV),and sevoflurane+PEMF treatment group(SEV+PEMF).Rats in the sevoflurane group and sevoflurane+PEMF group passively inhaled 2.5％sevoflurane for 4 h,while rats in the SEV+PEMF group were stimulated with 2 mT,15 Hz PEMF for 14 d(2 h/day).The cognitive function of rats was evaluated via the Morris water maze testing.The serum concentrations of tumor necrosis factor-α(TNF-α),interleukin-1 β(IL-1β),IL-6,neuron specific enolase(NSE),and β amyloid protein(Aβ),as well as the levels of nerve growth factor(NGF)and brain-derived neurotrophic factor(BDNF)in hippocampal tissue,were de-termined via ELISA.Western blot was used to detect the expression of autophagy-related biomarkers in rat hippocampal tissue.Secondly,30 elderly male rats were randomly divided into three groups:SEV group,SEV+PEMF group,and SEV+3-MA(the autophagy inhibitor)+PEMF group.The Morris water maze experiment was used to evaluate the change of PEMF-induced improvement of cognitive function sevoflurane-inhaled elderly rats following the autophagy inhi-bition.Results:PEMF inhibited sevoflurane-induced increase in escape latency and overall swimming distance,as well as the decrease in the number of crossing target quadrant(P＜0.05);PEMF decreased the levels of serum Aβ and NSE in elderly rats inhaled with sevoflurane(P＜0.05),decreased the levels of TNF-α,IL-1β,and IL-6(P＜0.05),increased the levels of NGF and BDNF in hippocampal tissue(P＜0.05),inhibited neuronal apoptosis in hip-pocampal tissue and increased its autophagy level(P＜0.05).Following inhibition of autophagy with 3-MA,the im-provement of PEMF on the decreased learning and memory ability induced by sevoflurane in elderly rats was significantly inhibited(P＜0.05).Conclusion:PEMF can effectively inhibit sevoflurane-induced cognitive dysfunction in elderly rats by regulating the autophagy of hippocampal neuronal cells.

Objective:In the context of the aging trend of China's population,it aims to analyze the trend of elderly disabled population growth in various regions and calculate the potential payment pressure of long-term care insurance for the disabled population,thereby providing policy implications for China's long-term care insurance system.Methods:A model for estimating the amount of expenditure on long-term care insurance fund was constructed,using the population age structure of each province in China from 2025 to 2060 obtained from the random forest model,and combining multi-source data such as the disability rate of the elderly population and the care cost of disabled elderly people to predict the number of elderly disabled people and the payment amount of long-term care insurance in each province in the future.Results:The aging trend in China will continue to intensify and exhibit a significant structural feature.The peak of the aging ratio in northeastern regions such as Inner Mongolia,Heilongjiang,Jilin,and Liaoning will come earliest,while the number of elderly people with disabilities in provinces with large populations such as Shandong,Sichuan,and Henan are relatively larger.Guangdong will have the largest number of disabled elderly people by 2055.Conclusion:It is suggested that the long-term care insurance system should be steadily advanced,with national-level support for the construction of the system in Northeast China and populous provinces.

Objective:In the context of the aging trend of China's population,it aims to analyze the trend of elderly disabled population growth in various regions and calculate the potential payment pressure of long-term care insurance for the disabled population,thereby providing policy implications for China's long-term care insurance system.Methods:A model for estimating the amount of expenditure on long-term care insurance fund was constructed,using the population age structure of each province in China from 2025 to 2060 obtained from the random forest model,and combining multi-source data such as the disability rate of the elderly population and the care cost of disabled elderly people to predict the number of elderly disabled people and the payment amount of long-term care insurance in each province in the future.Results:The aging trend in China will continue to intensify and exhibit a significant structural feature.The peak of the aging ratio in northeastern regions such as Inner Mongolia,Heilongjiang,Jilin,and Liaoning will come earliest,while the number of elderly people with disabilities in provinces with large populations such as Shandong,Sichuan,and Henan are relatively larger.Guangdong will have the largest number of disabled elderly people by 2055.Conclusion:It is suggested that the long-term care insurance system should be steadily advanced,with national-level support for the construction of the system in Northeast China and populous provinces.

Objective:In the context of the aging trend of China's population,it aims to analyze the trend of elderly disabled population growth in various regions and calculate the potential payment pressure of long-term care insurance for the disabled population,thereby providing policy implications for China's long-term care insurance system.Methods:A model for estimating the amount of expenditure on long-term care insurance fund was constructed,using the population age structure of each province in China from 2025 to 2060 obtained from the random forest model,and combining multi-source data such as the disability rate of the elderly population and the care cost of disabled elderly people to predict the number of elderly disabled people and the payment amount of long-term care insurance in each province in the future.Results:The aging trend in China will continue to intensify and exhibit a significant structural feature.The peak of the aging ratio in northeastern regions such as Inner Mongolia,Heilongjiang,Jilin,and Liaoning will come earliest,while the number of elderly people with disabilities in provinces with large populations such as Shandong,Sichuan,and Henan are relatively larger.Guangdong will have the largest number of disabled elderly people by 2055.Conclusion:It is suggested that the long-term care insurance system should be steadily advanced,with national-level support for the construction of the system in Northeast China and populous provinces.

Objective:In the context of the aging trend of China's population,it aims to analyze the trend of elderly disabled population growth in various regions and calculate the potential payment pressure of long-term care insurance for the disabled population,thereby providing policy implications for China's long-term care insurance system.Methods:A model for estimating the amount of expenditure on long-term care insurance fund was constructed,using the population age structure of each province in China from 2025 to 2060 obtained from the random forest model,and combining multi-source data such as the disability rate of the elderly population and the care cost of disabled elderly people to predict the number of elderly disabled people and the payment amount of long-term care insurance in each province in the future.Results:The aging trend in China will continue to intensify and exhibit a significant structural feature.The peak of the aging ratio in northeastern regions such as Inner Mongolia,Heilongjiang,Jilin,and Liaoning will come earliest,while the number of elderly people with disabilities in provinces with large populations such as Shandong,Sichuan,and Henan are relatively larger.Guangdong will have the largest number of disabled elderly people by 2055.Conclusion:It is suggested that the long-term care insurance system should be steadily advanced,with national-level support for the construction of the system in Northeast China and populous provinces.

Objective:In the context of the aging trend of China's population,it aims to analyze the trend of elderly disabled population growth in various regions and calculate the potential payment pressure of long-term care insurance for the disabled population,thereby providing policy implications for China's long-term care insurance system.Methods:A model for estimating the amount of expenditure on long-term care insurance fund was constructed,using the population age structure of each province in China from 2025 to 2060 obtained from the random forest model,and combining multi-source data such as the disability rate of the elderly population and the care cost of disabled elderly people to predict the number of elderly disabled people and the payment amount of long-term care insurance in each province in the future.Results:The aging trend in China will continue to intensify and exhibit a significant structural feature.The peak of the aging ratio in northeastern regions such as Inner Mongolia,Heilongjiang,Jilin,and Liaoning will come earliest,while the number of elderly people with disabilities in provinces with large populations such as Shandong,Sichuan,and Henan are relatively larger.Guangdong will have the largest number of disabled elderly people by 2055.Conclusion:It is suggested that the long-term care insurance system should be steadily advanced,with national-level support for the construction of the system in Northeast China and populous provinces.