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This study delved into the role of the PI3K/AKT signaling pathway and cuproptosis in steroid-induced osteonecrosis of the femoral head (SIONFH), assessing the therapeutic potential of the PI3K agonist 740Y-P. We analyzed femoral head specimens from SIONFH patients using DIA proteomics, identifying differentially expressed proteins linked to cuproptosis. In vitro, MC3T3-E1 cells treated with dexamethasone (DEX) exhibited hallmarks of cuproptosis, including downregulation of DLAT, PDHB, SLC25A3, and FDX1, increased copper ions, and reduced osteogenic potential, as shown by decreased ALP activity and RUNX2/BMP2 expression. The PI3K/AKT pathway’s modulation of FDX1 was key to cuproptosis regulation; activating it with 740Y-P restored FDX1 levels and partially recovered osteogenic capacity. An in vivo rat model of SIONFH treated with 740Y-P demonstrated improved bone parameters, reversed osteogenic suppression, and upregulated PI3K/AKT/FDX1 expression, validating the pathway’s role in cuproptosis and the agonist’s therapeutic potential for treating SIONFH and glucocorticoid-associated bone disorders.

Osteonecrosis of the femoral head (ONFH) is a refractory orthopedic condition characterized by bone cell ischemia, necrosis, bone trabecular fracture, and clinical symptoms such as pain, femoral head collapse, and joint dysfunction that can lead to disability. The disability rate of ONFH is very high, which imposes a significant economic burden on both families and society. Steroid-associated osteonecrosis of the femoral head (SANFH) is the most common type of ONFH. However, the pathogenesis of SANFH remains unclear, and it is an urgent challenge for orthopedic surgeons to explore it. In this paper, the pathogenesis of SANFH and its related signaling pathways were briefly reviewed to enhance comprehension of the pathogenesis and prevention of SANFH.

teroid-induced osteonecrosis of the femoral head (SONFH) is a severe bone disorder caused by long-term glucocorticoid administration and is characterized by osteoblast apoptosis. Oleuropein (OLP), a natural compound with anti-inflammatory and antioxidant properties, has demonstrated anti-apoptotic potential in bone-related diseases. However, its therapeutic role in SONFH has not yet been elucidated. This study aimed to investigate the therapeutic effects of OLP on SONFH and elucidate its underlying molecular mechanisms. In vitro, MC3T3-E1 osteoblasts treated with methylprednisolone (MPS) were co-incubated with OLP. Cell viability was assessed using a CCK-8 assay and live/dead cell staining. In vivo, a rat SONFH model was established with lipopolysaccharide and MPS, followed by OLP treatment. Bone microstructure was analyzed by micro-computed tomography and histopathological staining (H&E, Masson, Goldner). Network pharmacology and proteomics analyses were used to identify key targets and pathways related to the effects of OLP on SONFH. Apoptosis was examined with flow cytometry, TUNEL staining and ELISA. Protein and mRNA expression levels of relevant targets and pathways were examined with western blotting and quantitative real-time polymerase chain reaction. OLP significantly reversed MPS-induced osteoblast apoptosis and enhanced cell viability. In SONFH rats, OLP reduced empty lacunae, restored trabecular bone structure, and improved collagen organization. Molecular docking confirmed OLP’s binding to AKT and Bcl2. Network pharmacology and proteomics highlighted apoptosis regulation, PI3K-AKT signaling, and cell cycle control as key mechanisms. Furthermore, OLP activated the PI3K-AKT-Bcl2 pathway, increasing p-PI3K, p-AKT, and Bcl2 levels while decreasing Caspase3 and Caspase9. OLP also promoted osteogenesis (upregulated ALP and Runx2) and angiogenesis (increased vWF and CD31). OLP alleviates SONFH by inhibiting osteoblast apoptosis and promoting osteogenesis and angiogenesis through activation of the PI3K-AKT-Bcl2 pathway. These findings support OLP as a promising natural compound for early intervention in SONFH.

The onset of osteonecrosis of the femoral head (ONFH) is intimately associated with the extensive administration of glucocorticoids (GCs). Long‐term stimulation of GCs can induce oxidative stress in both osteoclasts (OCs) and osteoblasts (OBs), resulting in the disturbance of bone remodelling. An alkaloid named crebanine (CN) demonstrates pharmacological properties including anti‐inflammation and reactive oxygen species (ROS) modulation. Our objective is to assess the therapeutic potential of CN in treating ONFH and elucidate the associated underlying mechanisms. The network pharmacology analysis uncovered that CN played a role in regulating ROS metabolism. In vitro, CN demonstrated its ability to reduce the dexamethasone (DEX)‐stimulated generation of OCs and suppress their resorptive function by downregulating the level of osteoclast marker genes. Concurrently, CN also mitigated DEX‐induced damage to OBs, facilitating the restoration of osteoblast marker gene expression, cellular differentiation and function. These effects were achieved by CN augmenting the antioxidant system to reduce intracellular ROS levels. Furthermore, in vitro results were corroborated by micro‐CT and histological data, which also showed that CN attenuated MPS‐induced ONFH in mice. This study highlights the therapeutic potential of CN in counteracting GCs‐induced ONFH.

The imbalance between osteogenesis and adipogenesis in the femoral head is a major pathogenic mechanism underlying glucocorticoid (GC)-induced osteonecrosis of the femoral head (GIONFH), yet its specific molecular pathogenesis remains elusive. Dexras1 has been reported to mediate GC-induced osteogenesis-adipogenesis imbalance in osteoporosis, but its functional role and related mechanisms in GIONFH remain unclear. Here, we first demonstrated that Dexras1 expression was upregulated in rat models of GIONFH. Using Dexras1-knockout (KO) rats, radiographic and histological assessments demonstrated that Dexras1 ablation attenuated the osteonecrosis severity and restored the osteogenesis-adipogenesis balance in the femoral head. Results from RT-PCR, western blotting, alkaline phosphatase staining, and Oil Red O staining showed that Dexras1 KO promoted osteogenesis while inhibiting adipogenesis in bone marrow mesenchymal stem cells (BMSCs), whereas Dexras1 overexpression exerted the opposite effects. Additionally, TUNEL, Cell Counting Kit-8, and flow cytometry assays revealed that Dexras1 had no impact on BMSC viability in the rat GIONFH model. Dihydroethidium (DHE) staining and superoxide dismutase (SOD) activity assays further confirmed that Dexras1 was not involved in GC-induced oxidative stress in the femoral head. Finally, we confirmed that the upregulation of peroxisome proliferator-activated receptor γ (PPARγ) and downregulation of Wnt signaling pathways were potential mechanisms underlying Dexras1-mediated osteogenesis-adipogenesis imbalance by RNA sequencing and some in vitro experiments. Collectively, our results demonstrate that Dexras1 is critical for GIONFH development, as it mediates the imbalance between osteogenesis and adipogenesis.

Autophagy may play an important role in the occurrence and development of glucocorticoid‐induced osteonecrosis of the femoral head (GC‐ONFH). Lithium is a classical autophagy regulator, and lithium can also activate osteogenic pathways, making it a highly promising therapeutic agent for GC‐ONFH. We aimed to evaluate the potential therapeutic effect of lithium on GC‐ONFH. For in vitro experiments, primary osteoblasts of rats were used for investigating the underlying mechanism of lithium's protective effect on GC‐induced autophagy levels and osteogenic activity dysfunction. For in vivo experiments, a rat model of GC‐ONFH was used for evaluating the therapeutic effect of oral lithium on GC‐ONFH and underlying mechanism. Findings demonstrated that GC over‐activated the autophagy of osteoblasts and reduced their osteogenic activity. Lithium reduced the over‐activated autophagy of GC‐treated osteoblasts through PI3K/AKT/mTOR signalling pathway and increased their osteogenic activity. Oral lithium reduced the osteonecrosis rates in a rat model of GC‐ONFH, and restrained the increased expression of autophagy related proteins in bone tissues through PI3K/AKT/mTOR signalling pathway. In conclusion, lithium can restrain over‐activated autophagy by activating PI3K/AKT/mTOR signalling pathway and up‐regulate the expression of genes for bone formation both in GC induced osteoblasts and in a rat model of GC‐ONFH. Lithium may be a promising therapeutic agent for GC‐ONFH. However, the role of autophagy in the pathogenesis of GC‐ONFH remains controversial. Studies are still needed to further explore the role of autophagy in the pathogenesis of GC‐ONFH, and the efficacy of lithium in the treatment of GC‐ONFH and its underlying mechanisms.

Steroid-induced osteonecrosis of the femoral head (SONFH) is a severe bone disease associated with long-term glucocorticoid use, characterized by impaired bone metabolism and vascular insufficiency. Bilobalide (BB), a natural sesquiterpene from Ginkgo biloba, exhibits anti-apoptotic, antioxidant, and pro-angiogenic properties, yet its role in SONFH remains unclear. We integrated network pharmacology and molecular docking to predict the targets and pathways of BB in SONFH. Key targets were validated using molecular docking software. For in vivo experiments, a rat SONFH model was established using methylprednisolone (MPS), and BB was administered orally. Micro-CT, H&E staining, TUNEL assay, and immunohistochemistry were employed to evaluate bone microstructure, apoptosis, and the expression of osteogenic and angiogenic markers. Immunofluorescence was used to assess HIF-1α expression in rat femoral head tissues. For in vitro experiments, MC3T3-E1 osteoblasts were treated with dexamethasone(DEX) and BB. Cell viability was detected using the CCK-8 assay, and the protein levels of the HIF-1α and ERK pathways were examined by Western blot. Network pharmacology identified 94 common targets between BB and SONFH, with enrichment in HIF-1 and ERK signaling pathways. Molecular docking confirmed strong binding affinities between BB and core targets. In MPS-induced rats, BB treatment significantly improved bone mineral density, trabecular microstructure, and reduced osteocyte apoptosis. BB also upregulated HIF-1α, Runx2, OCN, CD31, and VEGF expression, indicating enhanced osteogenesis and angiogenesis. In vitro, BB rescued dexamethasone-induced suppression of osteoblast viability and upregulated the ERK/HIF-1α pathway. Bilobalide attenuates SONFH progression by activating the ERK/HIF-1α signaling pathway, promoting osteogenesis and angiogenesis, and reducing osteocyte apoptosis. These findings highlight BB as a promising candidate for SONFH prevention and support the utility of network pharmacology in mechanistic natural product research.

Bone marrow edema (BME), a notable manifestation during the progression of osteonecrosis of the femoral head (ONFH), exhibits significant associations with femoral head collapse, pain, and prognosis, howeverits’ pathogenesis remains underexplored. In this study, specimens from patients undergoing total hip arthroplasty (THA) were analyzed. The results revealed significantly higher Visual Analog Scale (VAS) scores and CT low-density area ratio in the BME group compared to the control group. Furthermore, Sirius Red staining exhibited fibrotic tissue in both necrotic and sclerotic areas, with more pronounced effects in the BME group. Meanwhile, data-independent Acquisition (DIA) proteomics technology was utilized to identify differentially expressed proteins (DEPs) within bone tissue. 141, 299 and 852 DEPs were identified in femoral neck, necrotic and sclerotic regions, respectively. Immune responses, inflammatory reactions and oxidative stress were markedly altered in ONFH cases with BME. In bone tissue, the levels of malondialdehyde (MDA) and proteins associated with osteoclast activity were found to be elevated in the BME group. In conclusion, BME in ONFH at pericollapse stage is associated with inflammation, fibrosis, heightened oxidative stress and increased osteoclast activity. These factors collectively elevated the risk of collapse or re-collapse. Targeted interventions aimed at neutralizing these risk factors show potential in slowing down the progression of the disease.

To detect and compare the bone microstructure and osteoblast and osteoclast activity in different regions of human osteonecrotic femoral heads. Osteonecrotic femoral heads were obtained from 10 patients (6 males, 4 females; Ficat IV) undergoing total hip arthroplasty between 2011 and 2013. The samples were divided into subchondral bone, necrotic, sclerotic, and healthy regions based on micro-computed tomography (CT) images. The bone microstructure, micromechanics, and osteoblast and osteoclast activity were assessed using micro-CT, pathology, immunohistochemistry, nanoindentation, reverse transcription polymerase chain reaction (RT-PCR), tartrate-resistant acid phosphatase staining and Western blotting. (1) The spatial structure of the bone trabeculae differed markedly in the various regions of the osteonecrotic femoral heads. (2) The elastic modulus and hardness of the bone trabeculae in the healthy and necrotic regions did not differ significantly (P >0.05). (3) The subchondral bone and necrotic region were positive on TRAP staining, while the other regions were negative. (4) On immunohistochemical staining, RANK and RANKL staining intensities were increased significantly in the subchondral bone and necrotic region compared with the healthy region, while RUNX2 and BMP2 staining intensities were increased significantly in the sclerotic region compared with the necrotic region. (5) OPG, RANK, RANKL, RUNX2, BMP2, and BMP7 protein levels were greater in the necrotic and sclerotic region than in subchondral bone and the healthy region. The micromechanical properties of bone trabeculae in the necrotic region did not differ significantly from the healthy region. During the progress of osteonecrosis, the bone structure changed markedly. Osteoclast activity increased in subchondral bone and the necrotic region while osteoblast activity increased in the sclerotic region. We speculate that the altered osteoblast and osteoclast activity leads to a reduction in macroscopic mechanical strength.

Steroid-induced osteonecrosis of the femoral head (SONFH) is the predominant cause of non-traumatic osteonecrosis of the femoral head (ONFH). Impaired blood supply and reduced osteogenic activity of the femoral head are the key pathogenic mechanisms of SONFH. Fibroblast growth factor 23 (FGF23) levels are not only a biomarker for early vascular lesions caused by abnormal mineral metabolism, but can also act directly on the peripheral vascular system, leading to vascular pathology. The aim of this study was to observe the role of FGF23 on bone microarchitecture and vascular endothelium, and to investigate activation of pyroptosis in SONFH. Lipopolysaccharide (LPS) combined with methylprednisolone (MPS) was applied for SONFH mouse models, and adenovirus was used to increase or decrease the level of FGF23. Micro-CT and histopathological staining were used to observe the structure of the femoral head, and immunohistochemical staining was used to observe the vascular density. The cells were further cultured in vitro and placed in a hypoxic environment for 12 h to simulate the microenvironment of vascular injury during SONFH. The effect of FGF23 on osteogenic differentiation was evaluated using alkaline phosphatase staining, alizarin red S staining and expression of bone formation-related proteins. Matrigel tube formation assay in vitro and immunofluorescence were used to detect the ability of FGF23 to affect endothelial cell angiogenesis. Steroids activated the pyroptosis signaling pathway, promoted the secretion of inflammatory factors in SONFH models, led to vascular endothelial dysfunction and damaged the femoral head structure. In addition, FGF23 inhibited the HUVECs angiogenesis and BMSCs osteogenic differentiation. FGF23 silencing attenuated steroid-induced osteonecrosis of the femoral head by inhibiting the pyroptosis signaling pathway, and promoting osteogenic differentiation of BMSCs and angiogenesis of HUVECs in vitro.