Objective:To elucidate the molecular mechanisms through which high-dose dexamethasone exerts long-term effects on bone marrow mesenchymal stem cells (BMSCs), specifically its role in suppressing osteogenic differentiation, accelerating cellular senescence, triggering the senescence-associated secretory phenotype (SASP), and inducing apoptosis.Methods:Primary rat BMSCs were isolated and treated with high-dose dexamethasone (1×10 -4 mol/L) to establish the experimental group, while untreated cells served as the control. The gene and protein expression levels of osteogenic markers, bone alkaline phosphatase (bALP) and Runt-related transcription factor 2 (Runx2), were analyzed in both groups. Cellular senescence was evaluated using senescence-associated β-galactosidase (SA-β-gal) staining. The expression of senescence-related markers (P16 and P21), components of the senescence-associated secretory phenotype (SASP), including tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and interferon (IFN)-γ, as well as apoptosis-related proteins (Bcl-2, Bax, and Cleaved-Caspase-3), and key factors of the Nrf2/HO-1 signaling pathway were assessed at both transcriptional and protein levels using qRT-PCR, immunofluorescence, and Western-blot analyses. These comprehensive evaluations aimed to determine the senescent state, apoptotic features, and alterations in osteogenic differentiation of BMSCs. Results:Following treatment with dexamethasone and subsequent withdrawal, both qRT-PCR and Western blot analyses indicated a significant reduction in the expression of the osteogenic markers bALP and Runx2 at both mRNA and protein levels. The proportion of SA-β-gal positive cells was markedly higher in the dexamethasone group (74.33%±6.89%) than in the control group (20.30%±1.57%, t=17.300, P<0.001). qRT-PCR analysis revealed upregulated mRNA expression of the senescence-related genes P16 and P21 after dexamethasone treatment, which was further supported at the protein level by immunofluorescence showing increased P21 expression. Western-blot results confirmed that protein expression levels of P16 and P21 were significantly elevated in the dexamethasone group (7.025±0.255 and 6.362±0.456, respectively) compared with the control group (1.016±0.115 and 0.816±0.172; both P<0.05). Furthermore, gene expression levels of the senescence-associated secretory phenotype (SASP) factors TNF-α and IL-1β were significantly increased (TNF-α: 3.539±0.599 vs. 0.742±0.095; IL-1β: 4.469±0.331 vs. 0.799±0.175; both P<0.05), and their protein expression was consistently upregulated as validated by Western-blot. Additionally, protein expression levels of TNF-α, IL-1β, and IFN-γ were significantly higher in the dexamethasone-treated group (3.476±0.932 vs. 0.945±0.095; 4.111±0.220 vs. 0.762±0.105; 2.155±0.240 vs. 0.656±0.104; all P<0.05).Western-blot analysis also demonstrated that protein expression of Nrf2 and HO-1 was significantly suppressed in the dexamethasone group (0.21±0.07 and 0.19±0.06, respectively) compared with the control group (1.13±0.15 and 0.92±0.21; P<0.05). Moreover, Western-blot analysis revealed that the expression levels of the pro-apoptotic proteins Bax and Cleaved-Caspase-3 were significantly up, regulated in the dexamethasone, treated BMSCs (Bax: 3.673±0.397 vs. 0.453±0.111; Cleaved-Caspase-3: 3.863±0.399 vs. 0.465±0.057), while the expression of the anti-apoptotic protein Bcl-2 was markedly down, regulated (0.959±0.073 vs. 2.126±0.195), with all differences being statistically significant ( P<0.05). Conclusions:High-dose dexamethasone treatment of BMSCs, followed by withdrawal of dexamethasone, induces cellular senescence and enhances the expression of the senescence-associated secretory phenotype (SASP) through suppression of the Nrf2/HO-1 signaling pathway. Concurrently, it promotes apoptosis by activating the mitochondrial apoptotic pathway, collectively leading to impaired osteogenic differentiation of BMSCs.

Objective:To elucidate the molecular mechanisms through which high-dose dexamethasone exerts long-term effects on bone marrow mesenchymal stem cells (BMSCs), specifically its role in suppressing osteogenic differentiation, accelerating cellular senescence, triggering the senescence-associated secretory phenotype (SASP), and inducing apoptosis.Methods:Primary rat BMSCs were isolated and treated with high-dose dexamethasone (1×10 -4 mol/L) to establish the experimental group, while untreated cells served as the control. The gene and protein expression levels of osteogenic markers, bone alkaline phosphatase (bALP) and Runt-related transcription factor 2 (Runx2), were analyzed in both groups. Cellular senescence was evaluated using senescence-associated β-galactosidase (SA-β-gal) staining. The expression of senescence-related markers (P16 and P21), components of the senescence-associated secretory phenotype (SASP), including tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and interferon (IFN)-γ, as well as apoptosis-related proteins (Bcl-2, Bax, and Cleaved-Caspase-3), and key factors of the Nrf2/HO-1 signaling pathway were assessed at both transcriptional and protein levels using qRT-PCR, immunofluorescence, and Western-blot analyses. These comprehensive evaluations aimed to determine the senescent state, apoptotic features, and alterations in osteogenic differentiation of BMSCs. Results:Following treatment with dexamethasone and subsequent withdrawal, both qRT-PCR and Western blot analyses indicated a significant reduction in the expression of the osteogenic markers bALP and Runx2 at both mRNA and protein levels. The proportion of SA-β-gal positive cells was markedly higher in the dexamethasone group (74.33%±6.89%) than in the control group (20.30%±1.57%, t=17.300, P<0.001). qRT-PCR analysis revealed upregulated mRNA expression of the senescence-related genes P16 and P21 after dexamethasone treatment, which was further supported at the protein level by immunofluorescence showing increased P21 expression. Western-blot results confirmed that protein expression levels of P16 and P21 were significantly elevated in the dexamethasone group (7.025±0.255 and 6.362±0.456, respectively) compared with the control group (1.016±0.115 and 0.816±0.172; both P<0.05). Furthermore, gene expression levels of the senescence-associated secretory phenotype (SASP) factors TNF-α and IL-1β were significantly increased (TNF-α: 3.539±0.599 vs. 0.742±0.095; IL-1β: 4.469±0.331 vs. 0.799±0.175; both P<0.05), and their protein expression was consistently upregulated as validated by Western-blot. Additionally, protein expression levels of TNF-α, IL-1β, and IFN-γ were significantly higher in the dexamethasone-treated group (3.476±0.932 vs. 0.945±0.095; 4.111±0.220 vs. 0.762±0.105; 2.155±0.240 vs. 0.656±0.104; all P<0.05).Western-blot analysis also demonstrated that protein expression of Nrf2 and HO-1 was significantly suppressed in the dexamethasone group (0.21±0.07 and 0.19±0.06, respectively) compared with the control group (1.13±0.15 and 0.92±0.21; P<0.05). Moreover, Western-blot analysis revealed that the expression levels of the pro-apoptotic proteins Bax and Cleaved-Caspase-3 were significantly up, regulated in the dexamethasone, treated BMSCs (Bax: 3.673±0.397 vs. 0.453±0.111; Cleaved-Caspase-3: 3.863±0.399 vs. 0.465±0.057), while the expression of the anti-apoptotic protein Bcl-2 was markedly down, regulated (0.959±0.073 vs. 2.126±0.195), with all differences being statistically significant ( P<0.05). Conclusions:High-dose dexamethasone treatment of BMSCs, followed by withdrawal of dexamethasone, induces cellular senescence and enhances the expression of the senescence-associated secretory phenotype (SASP) through suppression of the Nrf2/HO-1 signaling pathway. Concurrently, it promotes apoptosis by activating the mitochondrial apoptotic pathway, collectively leading to impaired osteogenic differentiation of BMSCs.

Objective To explore the therapeutic mechanism of compound Yuye Decoction against diabetic cardiomyopathy(DCM).Methods Drugbank,Gene Cards,OMIM and PharmGKb databases were used to obtain DCM-related targets,and the core targets were identified and functionally annotated by protein-protein interaction network analysis followed by GO and KEGG enrichment analysis.The"Traditional Chinese Medicine-Key Component-Key Target-Key Pathway"network was constructed using Cytoscape 3.9.1,and molecular docking was carried out for the key components and the core targets.In the animal experiment,Wistar rat models of DCM were treated with normal saline or Yuye Decoction by gavage at low(0.29 g/kg)and high(1.15 g/kg)doses for 8 weeks,and the changes in cardiac electrophysiology and histopathology were evaluated.The changes in serum levels of LDH,CK,and CK-MB were examined,and myocardial expressions of PI3K,P-PI3K,Akt,P-AKT,BAX,IL-6,and TNF-α were detected using Western blotting.Results We identified 61 active compounds in Yuye Decoction with 1057 targets,3682 DCM-related disease targets,and 551 common targets between them.Enrichment of the core targets suggested that apoptosis,inflammation and the PI3K/Akt pathways were the key signaling pathways for DCM treatment.Molecular docking studies showed that the active components in Yuye Decoction including gold amidohydroxyethyl ester and kaempferol had strong binding activities with AKT1 and PIK3R1.In DCM rat models,treatment with Yuye Decoction significantly alleviated myocardial pathologies,reduced serum levels of LDH,CK and CK-MB,lowered myocardial expressions of BAX,IL-6 and TNF-α,and increased the expressions of P-PI3K and P-AKT.Conclusion The therapeutic effect of compound Yuye Decoction against DCM is mediated by its multiple active components that act on multiple targets and pathways to inhibit cardiomyocyte apoptosis and inflammatory response by regulating the PI3K/Akt signaling pathway.

Objective To explore the therapeutic mechanism of compound Yuye Decoction against diabetic cardiomyopathy(DCM).Methods Drugbank,Gene Cards,OMIM and PharmGKb databases were used to obtain DCM-related targets,and the core targets were identified and functionally annotated by protein-protein interaction network analysis followed by GO and KEGG enrichment analysis.The"Traditional Chinese Medicine-Key Component-Key Target-Key Pathway"network was constructed using Cytoscape 3.9.1,and molecular docking was carried out for the key components and the core targets.In the animal experiment,Wistar rat models of DCM were treated with normal saline or Yuye Decoction by gavage at low(0.29 g/kg)and high(1.15 g/kg)doses for 8 weeks,and the changes in cardiac electrophysiology and histopathology were evaluated.The changes in serum levels of LDH,CK,and CK-MB were examined,and myocardial expressions of PI3K,P-PI3K,Akt,P-AKT,BAX,IL-6,and TNF-α were detected using Western blotting.Results We identified 61 active compounds in Yuye Decoction with 1057 targets,3682 DCM-related disease targets,and 551 common targets between them.Enrichment of the core targets suggested that apoptosis,inflammation and the PI3K/Akt pathways were the key signaling pathways for DCM treatment.Molecular docking studies showed that the active components in Yuye Decoction including gold amidohydroxyethyl ester and kaempferol had strong binding activities with AKT1 and PIK3R1.In DCM rat models,treatment with Yuye Decoction significantly alleviated myocardial pathologies,reduced serum levels of LDH,CK and CK-MB,lowered myocardial expressions of BAX,IL-6 and TNF-α,and increased the expressions of P-PI3K and P-AKT.Conclusion The therapeutic effect of compound Yuye Decoction against DCM is mediated by its multiple active components that act on multiple targets and pathways to inhibit cardiomyocyte apoptosis and inflammatory response by regulating the PI3K/Akt signaling pathway.

Objective To investigate the effects of Yuye Decoction(YYD)on diabetic nephropathy(DN)rats with Qi and Yin deficiency based on intestinal flora and intestinal mucosal barrier.Methods The content of the active ingredients puerarin,mangiferin and calycosin 7-O-β-D-glucopyranoside in YYD freeze dried powder was tested by HPLC to control the quality of YYD freeze dried powder.Forty-five Wistar rats were randomly divided into normal group(NC group),Qi-Yin deficiency DN group(M group)and YYD administration group(YYD group;5.03 g·kg-1)according to body weight.Intraperitoneal injections of streptozotocin(STZ)at a dose of 25 mg·kg-1 were administered,accompanied by oral gavage of adix Aconiti Lateralis,Citri Reticulatae Pericarpium Viride and Aurantii Fructus for 8 weeks to establish a Qi-Yin deficiency DN model in rats.During this period,rats in the YYD group were also treated with YYD extract.Weekly body weight and blood glucose levels were monitored for each group,along with observations of physical signs,food and water consumption,swimming time,and urine output in the rats.After 8 weeks,serum levels of cholesterol(TC),triglycerides(TG),low-density lipoprotein(LDL-C),high-density lipoprotein(HDL-C),serum creatinine(SCr)and urinary nitrogen(BUN)were analyzed in rats using automatic biochemical analysis.Hematoxylin-eosin staining(HE)was used to observe the pathological changes in the kidney and colon tissues.Enzyme-linked immunosorbent assay(ELISA)was used to measure urine protein concentration and serum levels of IgG,IgM,cAMP and cGMP.16SrDNA sequencing was used to sequence faecal flora and some flora were validated by quantitative real-time fluorescence PCR(qRT-PCR).Western blot method was used to measure the levels of intestinal barrier proteins and inflammatory factor proteins.Results The yield of YYD freeze-dried powder was 27.36%and the content of the active ingredients in YYD was 0.3496 mg·g-1 for puerarin,0.1851 mg·g-1 for mangiferin and 0.0429 mg·g-1 for calycosin 7-O-β-D-glucopyranoside.The results of animal experiments indicated that compared with Qi and Yin deficiency DN rats,YYD significantly improved the symptoms of lethargy and fatigue,increased swimming time,reduced water intake and increased food intake;increased the abundance of Bacteroidetes and decreased the abundance of Firmicutes in feces.Furthermore,according to measurements of blood lipids,blood glucose,renal function,IgG and IgM,as well as cAMP and cGMP,which are the energy homeostasis factors of the body,YYD could significantly improve the levels of these indicators in the model rats.HE staining showed that compared with model rats,YYD remarkably alleviated kidney and colon damage;inhibited the expression of inflammatory factors TNF-α and IL-6 in the kidney and colon,and markedly raised the expression levels of renal and colonic kinetic proteins CHRM3 and 5-HT3A as well as mucosal barrier proteins Occludin and ZO-1.Conclusion YYD play a role in preventing and treating in rats with Qi-Yin deficiency DN,and this effect may be related to YYD correcting intestinal flora dysbiosis,delaying intestinal mucosal damage and improving renal and colonic inflammation in the model rats.

Femoral neck fracture (FNF) in the elderly patients is currently a major health challenge worldwide, with excessive consumption of medical resources, high incidence of complications as well as suboptimal outcome and prognosis. Hip joint arthroplasty (HJA) has been the mainstream treatment for FNF in the elderly, but the conventional surgical approaches and techniques are still confronted with a series of bottlenecks such as dislocation, limp and limb length discrepancy. In recent years, direct anterior approach (DAA) for HJA (DAA-HJA) has been a major new choice in the field of joint replacement, which achieves improved clinical effectiveness of HJA in the treatment of elderly FNF, due to the fact that DAA approach involves the neuromuscular interface and accords with the idea of soft tissue retention and enhanced recovery after surgery. However, there is still a lack of unified understanding of standard technique and procedure of DAA-HJA in the treatment of elderly FNF. Therefore, relevant experts from the Hip Joint Group of Chinese Orthopedics Association of Chinese Medical Association, Youth Arthrology Group of Orthopedic Committee of PLA, Orthopedic Committee of Chongqing Medical Association, Branch of Orthopedic Surgeons of Chongqing Medical Doctor Association and Sport Medicine Committee of Chongqing Medical Association were organized to formulate the " Chinese expert consensus on the technical standard of direct anterior hip arthroplasty for elderly femoral neck fracture ( version 2023)" based on evidence-based medicine. This consensus mainly proposed 13 recommendations covering indications, surgical plans, prosthesis selections, surgical techniques and processes, and postoperative management of DAA-HJA in elderly patients with FNF, aiming to promote standardized, systematic and patient-specific diagnosis and treatment to improve the functional prognosis of the patients.

Effective bone repair and regeneration is crucial for treating skeletal tissue defects, including osteonecrosis, nonunion fractures, osteoporosis, and various other bone deficiencies. Exosomes, as cellular secretory vesicles, are pivotal in mediating intercellular communication through their cargo of proteins, lipids, and nucleic acids. Mesenchymal stem cell-derived exosomes, in particular, have emerged as promising agents in bone repair and regeneration, showing potential for practical application and clinical translation. Nonetheless, their functional capacity and therapeutic efficacy require enhancement. This review delineates exosome optimization strategies aimed at augmenting secretion and functionality, alongside the incorporation of exosome-functionalized biomaterials for bone healing. Evidence indicates that physical stimulation, molecular interventions, and small-molecule or biomaterial stimuli are effective in increasing exosome output. Moreover, engineering exosomes and their parental cells can further potentiate their therapeutic function. The amalgamation of exosomes with biomaterials represents a burgeoning approach in bone tissue engineering, offering novel therapeutic avenues. This comprehensive analysis aims to guide future applications and the clinical adoption of exosomes in bone tissue restoration.

Objective:To investigate the effects of Connexin-43 (Cx43) on osteoblasts proliferation and osteogenic differentiation and its regulatory mechanism.Methods:Osteoblasts were isolated and cultured in vitro. The osteogenic activity of osteoblasts was detected by alizarin red staining and alkaline phosphatase (ALP) staining after dexamethasone treatment. The expression of Cx43, Runt-related transcription factor 2 (Runx2), ALP, collagen I type (COL-I) and proliferation-related proteins PCNA and CDK4 in osteoblasts were detected by Western-blot. The expressions of osteoblast proteins were detected by immunofluorescence staining. The proliferation of osteoblasts was detected by CCK8 assay. The lentivirus-mediated Cx43 gene overexpression plasmid (Lv-Cx43) was constructed and transfected into osteoblasts. The osteogenic activity and proliferation ability of osteoblasts were further detected by the above methods. Cx43 in osteoblasts was overexpressed by pretreating PD98059. The osteogenic activity and proliferation of Cx43 in overexpressed osteoblasts was detected by CCK8 and alizarin red staining.Results:The isolated osteoblasts have osteogenic differentiation ability. Compared with the control group, 1×10 -6 mol/L dexamethasone treatment could reduce the formation of calcium nodules in osteoblasts. With the increase of dexamethasone treatment duration, the protein expression of Cx43, Runx2, ALP and COL-I in osteoblasts decreased gradually, while the expression of PCNA, CDK4 and p-ERK1/2 decreased. The OD values of normal osteoblasts at 0, 1, 2, 3 and 4 d were 0.316±0.043, 0.891±0.623, 1.683±0.154, 2.315±0.721 and 2.891±0.323, respectively. However, The OD values of osteoblasts treated with dexamethasone were 0.376±0.021, 0.657±0.121, 1.124±0.285, 1.521±0.272, 1.987±0.584, respectively. OD values of dexamethasone treated osteoblasts were lower than those of normal group at 2, 3 and 4 days ( P<0.05). The relative expression levels of Cx43 mRNA in control group, Lv-NC group and Lv-Cx43 group were 0.541±0.086, 0.598±0.018 and 1.000±0.082, respectively. The mRNA expression level of Cx43 in Lv-Cx43 group was higher than that in control group and Lv-NC group ( P<0.05). The ratio of Cx43 protein band to the gray value of GAPDH band in control group, Lv-NC group and Lv-Cx43 group were 0.816±0.737, 0.738±0.643 and 1.145±1.101, respectively. The expression level of Lv-Cx43 was higher than that in control group and Lv-NC group ( P<0.05). The expressions of Runx2, ALP, COL-I mRNA and related marker proteins in Lv-Cx43 group were higher than those in control group and Lv-NC group ( P<0.05). The number of calcium nodules in the Lv-Cx43 group was significantly higher than that in the control group and Lv-NC group. The OD value of osteoblasts and the number of calcium nodules in Lv-Cx43+PD98059 group were significantly lower than those in Lv-Cx43 group ( P<0.05). Conclusion:The proliferation and differentiation ability of osteoblasts is significantly decreased after the treatment of dexamethasone with decreased expression of Cx43. Overexpression of Cx43 can promote the proliferation and osteogenic differentiation of osteoblasts, which may be regulated through the ERK1/2 pathway.

Objective:To investigate the expression of connexin-43 (Cx43) in steroid-induced osteonecrosis of femoral head and osteoblasts in rats and its regulation mechanism.Methods:The model of steroid-induced osteonecrosis of femoral head (SIONFH) of rat was established. Micro-CT and HE staining were used to observe the degree of bone trabecular destruction and the incidence of empty lacunae. The expression levels of Cx43 and PI3K/Akt signaling pathway related molecules and osteoblast-related proteins in model group and control group were detected by RT-PCT and Western blot. The osteoblast (OB) of rats was further isolated and cultured in vitro. Under treatment of dexamethasone (Dex), Cx43 expression in OB cells was detected by Western blot and immunofluorescence. Western blot was used to detect the effect of glucocorticoid (GC) on the expression of related molecules of PI3K/Akt/β-catenin signaling pathway. Akt activator (SC79) and PI3K inhibitor (LY294002) were used to study the molecular mechanism of Dex regulation on Cx43 expression in OB cells. The regulatory relationship between β-catenin and Cx43 was investigated by immunoprecipitation and small interfere RNA (siRNA) technology.Results:The model of SIONFH in rats was successfully established, which proved that Cx43 expression level in the SIONFH model group was significantly lower than that in the control group, and the expression level of Cx43 was positively correlated with the expression of PI3K/Akt signaling pathway related molecules and osteoblast-related proteins Runx2, ALP and Collagen I Type (COL). In addition, in vitro culture of isolated rat OB cells, the expression of Cx43, p-PI3K, P-Akt and β-catenin in OB cells decreased gradually as the Dex action time went on. Moreover, SC79 pretreatment could significantly reverse the inhibitory effect of GCs on Cx43 expression, while LY294002 could significantly enhance the inhibitory effect of GCs on Cx43. In addition, the immunoprecipitation results showed that β-catenin expression was closely related to Cx43 expression, and further studies showed that β-catenin-siRNA could significantly down-regulate the expression of Cx43.Conclusion:Under the action of GC, the expression level of Cx43 in bone tissue and OB cells decreased significantly, and the possible mechanism was that GCs inhibited the expression of Cx43 by inhibiting the PI3K/Akt/β-catenin signaling pathway, which laid a new theoretical foundation for the further study of the role of Cx43 in the pathogenesis of steroid-induced femoral head necrosis.

Osteonecrosis of the femoral head (ONFH) is caused by the blockage of the blood supply of the femoral head due to by a variety of reasons, resulting in the death of the bone in the femoral head, which is characterized by osteonecrosis occurdead bone resorption-new bone formation. And total hip arthroplasty (THA) is the final choice for the vast majority of these patients. Though treating hard, it is necessary to choose an appropriate head-preserving treatment in the early stage to delay the time of THA.Methods to treat femoral head necrosis varies, however, it is still hard to have a uniform standard until now. Thus, this paper discusses the epidemiological characteristics, related risk factors, pathology, stage, current head-preserving methods and prognostic factors of femoral head necrosis, so as to further enhance clinicians' understanding of osteonecrosis of the femoral head and provide reference to choose more appropriate head-preserving methods for those patients. As demonstrated in literatures, in China, the incidence of non-traumatic ONFH in males is significantly higher than that in females, and it is more common in northern residents and urban residents. In addition, glucocorticoid intake, hyperlipidemia, heavy smoking and alcohol abuse tend to increase the risk of ONFH; Histologically, osteonecrosis and repair of the femoral head occurred after blood supply was blocked; In terms of pathological staging, Ficat staging is the most commonly used and most directly classification method; core decompression, non-vascularized bone grafting, vascularized bone grafting and osteotomy are still the mainstream surgical methods at present. Patient's age, etiology, stage, etc are important factors affecting the prognosis of ONFH. Therefore, surgeons can choose the most appropriate treatment for the patients according to their specific conditions and prognostic factors.