TLR4 stimulation and corticosteroid interactively induce osteonecrosis of the femoral head in rat

Identification of steroid-induced osteonecrosis of the femoral head biomarkers based on immunization and animal experiments

BACKGROUND

Steroid-induced osteonecrosis of femoral head (SONFH) is a severe health risk, and this study aims to identify immune-related biomarkers and pathways associated with the disease through bioinformatics analysis and animal experiments.

METHOD

Using SONFH-related datasets obtained from the GEO database, we performed differential expression analysis and weighted gene co-expression network analysis (WGCNA) to extract SONFH-related genes. A protein-protein interaction (PPI) network was then constructed, and core sub-network genes were identified. Immune cell infiltration and clustering analysis of SONFH samples were performed to assess differences in immune cell populations. WGCNA analysis was used to identify module genes associated with immune cells, and hub genes were identified using machine learning. Internal and external validation along with animal experiments were conducted to confirm the differential expression of hub genes and infiltration of immune cells in SONFH.

RESULTS

Differential expression analysis revealed 502 DEGs. WGCNA analysis identified a blue module closely related to SONFH, containing 1928 module genes. Intersection analysis between DEGs and blue module genes resulted in 453 intersecting genes. The PPI network and MCODE module identified 15 key targets enriched in various signaling pathways. Analysis of immune cell infiltration showed statistically significant differences in CD8 + t cells, monocytes, macrophages M2 and neutrophils between SONFH and control samples. Unsupervised clustering classified SONFH samples into two clusters (C1 and C2), which also exhibited significant differences in immune cell infiltration. The hub genes (ICAM1, NR3C1, and IKBKB) were further identified using WGCNA and machine learning analysis. Based on these hub genes, a clinical prediction model was constructed and validated internally and externally. Animal experiments confirmed the upregulation of hub genes in SONFH, with an associated increase in immune cell infiltration.

CONCLUSION

This study identified ICAM1, NR3C1, and IKBKB as potential immune-related biomarkers involved in immune cell infiltration of CD8 + t cells, monocytes, macrophages M2, neutrophils and other immune cells in the pathogenesis of SONFH. These biomarkers act through modulation of the chemokine signaling pathway, Toll-like receptor signaling pathway, and other pathways. These findings provide valuable insights into the disease mechanism of SONFH and may aid in future drug development efforts.

Canonical pathways for validating steroid-associated osteonecrosis in mice

The present study aimed to establish and evaluate a preclinical model of steroid-associated osteonecrosis (SAON) in mice. Sixteen 24-week-old male C57BL/6 mice were used to establish SAON by two intraperitoneal injections of lipopolysaccharide (LPS), followed by three subcutaneous injections of methylprednisolone (MPS). Each injection was conducted on working day, with an interval of 24 h. Six cycles of injections were conducted. Additional twelve mice (age- and gender-matched) were used as normal controls. At 2 and 6 weeks after completing induction, bilateral femora and bilateral tibiae were collected for histological examination, micro-CT scanning, and bulk RNA sequencing. All mice were alive until sacrificed at the indicated time points. The typical SAON lesion was identified by histological evaluation at week 2 and week 6 with increased lacunae and TUNEL+ osteocytes. Micro-CT showed significant bone degeneration at week 6 in SAON model. Histology and histomorphometry showed significantly lower Runx2+ area, mineralizing surface (MS/BS), mineral apposition rate (MAR), bone formation rate (BFR/BS), type H vessels, Ki67+ (proliferating) cells, and higher marrow fat fraction, osteoclast number and TNFα+ areas in SAON group. Bulk RNA-seq revealed changed canonical signaling pathways regulating cell cycle, angiogenesis, osteogenesis, and osteoclastogenesis in the SAON group. The present study successfully established SAON in mice with a combination treatment of LPS and MPS, which could be considered a reliable and reproducible animal model to study the pathophysiology and molecular mechanism of early-stage SAON and to develop potential therapeutic approaches for the prevention and treatment of SAON.

SOX9 Inhibits the Progression of Osteonecrosis of the Femoral Head via the Activation of the Wnt/Beta-Catenin Pathway

Background: In this study, we aimed to explore whether the SRY-box transcription factor 9 (SOX9) can play protective roles against the occurrence and development of osteonecrosis of the femoral head (ONFH) by regulating the proliferation, apoptosis, and osteogenic differentiation of human bone marrow stromal cells (hBMSCs) via the Wnt/β-catenin pathway.Methods: We used 1600 mg of glucocorticoid (GC) to induce hBMSCs to establish an ONFH cell model and performed various experiments. Reverse transcription-quantitative polymerase chain reaction and western blotting assays were used to determine the expression levels of SOX9 and osteoblast markers, such as the RUNX family transcription factor 2 (RUNX2), alkaline phosphatase (ALP), osterix, Wnt3a, and β-catenin. An ALP detection kit was used to measure the ALP activity. Flow cytometry and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays were performed to determine the cell viability.Results: GC treatment decreased the expression levels of RUNX2, ALP, and osterix, suppressed ALP activity, and inhibited SOX9 expression. SOX9 overexpression promoted GC-induced cell proliferation and decreased cell apoptosis. Additionally, hBMSCs were transfected with SOX9-small interfering RNA in GC treatment, and SOX9 knockdown was found to suppress the osteogenic differentiation of cells and decrease their viability.Conclusion: Our results revealed that SOX9 is related to the Wnt/β-catenin pathway in ONFH. Moreover, SOX9 participated in ONFH development by activating the Wnt/β-catenin pathway.

Effects of astragaloside IV on glucocorticoid-induced avascular necrosis of the femoral head via regulating Akt-related pathways

We investigated the role of astragaloside IV (AS-IV) in preventing glucocorticoid-induced avascular necrosis of the femoral head (ANFH) and the underlying molecular mechanisms. Network pharmacology was used to predict the molecular targets of AS-IV. Molecular dynamic simulations were performed to explore the binding mechanism and interaction mode between AS-IV and Akt. Rat models of glucocorticoid-induced ANFH with AS-IV intervention were established, and osteogenesis, angiogenesis, apoptosis and oxidative stress were evaluated before and after blocking the PI3K/Akt pathway with LY294002. The effects of glucocorticoid and AS-IV on bone marrow mesenchymal stem cells and human umbilical vein endothelial cells incubated with and without LY294002 were determined. Downregulated p-Akt expression could be detected in the femoral heads of glucocorticoid-induced ANFH patients and rats. AS-IV increased trabecular bone integrity and vessel density of the femoral head in the model rats. AS-IV increased Akt phosphorylation and upregulated osteogenesis-, angiogenesis-, apoptosis- and oxidative stress-related proteins and mRNA and downregulated Bax, cleaved caspase-3 and cytochrome c levels. AS-IV promoted human umbilical vein endothelial cell migration, proliferation and tube formation ability; bone marrow mesenchymal stem cell proliferation; and osteogenic differentiation under glucocorticoid influence. AS-IV inhibited apoptosis. LY294002 inhibited these effects. AS-IV prevented glucocorticoid-induced ANFH by promoting osteogenesis and angiogenesis via the Akt/Runx2 and Akt/HIF-1α/VEGF pathways, respectively, and suppressing apoptosis and oxidative stress via the Akt/Bad/Bcl-2 and Akt/Nrf2/HO-1 pathways, respectively.

Calycosin modulates inflammation via suppressing TLR4/NF-κB pathway and promotes bone formation to ameliorate glucocorticoid-induced osteonecrosis of the femoral head in rat

Glucocorticoid (GC) administration is one of the main causes of osteonecrosis of the femoral head (ONFH). Inflammation, especially the TLR4/NF-κB pathway, has been demonstrated to play a pivotal role in the pathogenesis of GC-induced ONFH. Calycosin, the main bioactive extract of Astragali Radix, could substantially regulate the TLR4/NF-κB pathway. Therefore, in this study, we hypothesized that calycosin could exert beneficial effects in GC-induced ONFH. In vitro, effects of calycosin on the osteogenic differentiation of human bone mesenchymal stem cells (hBMSCs) were determined using Alizarin red staining, alkaline phosphatase activity examination, and osteogenic-related gene assay. Meanwhile, inflammatory cytokines were detected by enzyme-linked immunosorbent assay. In vivo, 60 male Sprague-Dawley rats were randomly separated into three groups: the control group, the methylprednisolone (MPS) group, and the MPS + calycosin group. The results showed that calycosin could significantly promote dynamic bone formation and retard TLR4/NF-κB pathway. in vivo investigations indicated that calycosin could decrease the morbidity of ONFH and alleviate pathological manifestations within the femoral head. Meanwhile, calycosin could protect osseous blood supply and facilitate dynamic bone formation. The findings collectively demonstrated that calycosin could ameliorate GC-induced ONFH in rat and might become a potential candidate for pharmaceutical prevention of this intractable disease.

Atorvastatin Upregulates microRNA-186 and Inhibits the TLR4-Mediated MAPKs/NF-κB Pathway to Relieve Steroid-Induced Avascular Necrosis of the Femoral Head

Steroid-induced avascular necrosis of the femoral head (SANFH) is caused by the death of active components of the femoral head owing to hormone overdoses. The use of lipid-lowering drugs to prevent SANFH in animals inspired us to identify the mechanisms involving Atorvastatin (Ato) in SANFH. However, it is still not well understood how and to what extent Ato affects SANFH. This study aimed to figure out the efficacy of Ato in SANFH and the underlying molecular mechanisms. After establishment of the SANFH model, histological evaluation, lipid metabolism, inflammatory cytokines, oxidative stress, apoptosis, and autophagy of the femoral head were evaluated. The differentially expressed microRNAs (miRs) after Ato treatment were screened out using microarray analysis. The downstream gene and pathway of miR-186 were predicted and their involvement in SANFH rats was analyzed. OB-6 cells were selected to simulate SANFH in vitro. Cell viability, cell damage, inflammation responses, apoptosis, and autophagy were assessed. Ato alleviated SANFH, inhibited apoptosis, and promoted autophagy. miR-186 was significantly upregulated after Ato treatment. miR-186 targeted TLR4 and inactivated the MAPKs/NF-κB pathway. Inhibition of miR-186 reversed the protection of Ato on SANFH rats, while inhibition of TLR4 restored the protective effect of Ato. Ato reduced apoptosis and promoted autophagy of OB-6 cells by upregulating miR-186 and inhibiting the TLR4/MAPKs/NF-κB pathway. In conclusion, Ato reduced apoptosis and promoted autophagy, thus alleviating SANFH via miR-186 and the TLR4-mediated MAPKs/NF-κB pathway.

Magnesium and vitamin C supplementation attenuates steroid-associated osteonecrosis in a rat model

Magnesium (Mg)-based biometal attracts clinical applications due to its biodegradability and beneficial biological effects on tissue regeneration, especially in orthopaedics, yet the underlying anabolic mechanisms in relevant clinical disorders are lacking. The present study investigated the effect of magnesium (Mg) and vitamin C (VC) supplementation for preventing steroid-associated osteonecrosis (SAON) in a rat experimental model. In SAON rats, 50 mg/kg Mg, or 100 mg/kg VC, or combination, or water control was orally supplemented daily for 2 or 6 weeks respectively. Osteonecrosis was evaluated by histology. Serum Mg, VC, and bone turnover markers were measured. Microfil-perfused samples prepared for angiography and trabecular architecture were evaluated by micro-CT. Primary bone marrow cells were isolated from each group to evaluate their potentials in osteoblastogenesis and osteoclastogenesis. The mechanisms were tested in vitro. Histological evaluation showed SAON lesions in steroid treated groups. Mg and VC supplementation synergistically reduced the apoptosis of osteocytes and osteoclast number, and increased osteoblast surface. VC supplementation significantly increased the bone formation marker PINP, and the combination significantly decreased the bone resorption marker CTX. TNFα expression and oxidative injury were decreased in bone marrow in Mg/VC/combination group. Mg significantly increased the blood perfusion in proximal tibia and decreased the leakage particles in distal tibia 2 weeks after SAON induction. VC significantly elevated the osteoblast differentiation potential of marrow cells and improved the trabecular architecture. The combination supplementation significantly inhibited osteoclast differentiation potential of marrow cells. In vitro study showed promoting osteoblast differentiation effect of VC, and anti-inflammation and promoting angiogenesis effect of Mg with underlying mechanisms. Mg and VC supplementation could synergistically alleviate SAON in rats, indicating great translational potentials of metallic minerals for preventing SAON.

Bloodstream infections exacerbate incidence and severity of symptomatic glucocorticoid-induced osteonecrosis

BACKGROUND

Osteonecrosis is a common toxicity associated with glucocorticoid (e.g., dexamethasone and prednisone) treatment of children with acute lymphoblastic leukemia (ALL), but risk factors are incompletely defined. Infections are also a common complication of ALL therapy. Lipopolysaccharide (LPS) is used experimentally to mimic infection-related systemic effects. To our knowledge, the contribution of systemic infections to the risk of glucocorticoid-induced osteonecrosis has not been investigated.

PROCEDURE

Patients with ALL on St. Jude Total Therapy XV (n = 365) were assessed for documented bacteremia prior to development of osteonecrosis, which was confirmed by MRI, and graded using the National Cancer Institute's Common Terminology for Adverse Events (version 3.0). In a preclinical model, Balb/cJ mice treated with dexamethasone plus or minus LPS were assessed for frequency and severity of osteonecrosis and arteriopathy.

RESULTS

We found that patients with ALL who experienced bacteremia had a higher frequency of symptomatic osteonecrosis (≥grade 2) than those who did not (OR: 1.88; 95% CI, 1.03-3.41, P = 0.038). LPS exacerbated experimental dexamethasone-induced osteonecrosis. Mice treated with dexamethasone plus LPS had a higher incidence of osteonecrosis (P = 0.00086) and arteriopathy (P = 0.0047) than did those treated with dexamethasone alone, and the severity of osteonecrosis (P = 0.00045) and arteriopathy (P = 0.0048) was also more pronounced with the addition of LPS treatment. The increase in osteonecrosis was not explained by any alteration of dexamethasone pharmacokinetics by LPS.

CONCLUSIONS

These data identify systemic infection during ALL therapy as a novel risk factor in the development of glucocorticoid-induced osteonecrosis.

Epidermal growth factor (EGF) promotes bone healing in surgically induced osteonecrosis of the femoral head (ONFH)

Angiogenic effects of epidermal growth factor (EGF), a potent mitogen, have been demonstrated previously. Moreover, different in vitro studies showed that EGF affects processes associated with bone healing, such as osteoblast differentiation and bone resorption. The aim of this study was to investigate the effect of combined core decompression (CD) and recombinant human EGF (rhEGF) treatment on early-stage osteonecrosis of the femoral head (ONFH) surgically induced in rats. ONFH was induced by dissecting the cervical periosteum and placing a ligature tightly around the femoral neck. Thirty rats were assigned to one of the following groups (n = 10 each group): sham-operated control, CD, and CD+rhEGF group. rhEGF was injected intraosseously into infarcted areas 2 weeks after the surgery. Preservation of femoral head architecture was assessed at 8 weeks post treatment by radiographic and histomorphological analyses. Osteopontin (OPN) and cluster of differentiation 31 (CD31) were detected by immunochemistry, as indicators of bone remodeling and vascular density, respectively. Inter- and intra-group (non-operated left and operated right femur) differences in radiographic and histomorphological results were analyzed. The femoral head area and sphericity were more preserved in CD+rhEGF compared to CD and sham-control group. CD31 levels were significantly different between the three groups, and were higher in CD+rhEGF compared to CD group. OPN levels were increased in CD and CD+rhEGF groups compared to sham control, but with no significant difference between CD and CD+rhEGF groups. Overall, our results indicate that EGF promotes bone formation and microvascularization in ONFH and thus positively affects the preservation of femoral head during healing.

Animal models of steroid-induced osteonecrosis of the femoral head-a comprehensive research review up to 2018

Osteonecrosis of the femoral head (ONFH) is a significant cause of both pain and disability that often affects young adults during what ought to be their most productive age. Two broad categories of ONFH exist: traumatic and non-traumatic. Traumatic ONFH results from acute mechanical disruption of the femoral head's blood supply. Many factors that increase the risk of non-traumatic osteonecrosis have been identified. Steroid-induced osteonecrosis of the femoral head (SONFH) is the most common form of non-traumatic ONFH. Many hypotheses as to the pathogenesis of SONFH have been proposed, including intravascular thrombosis, abnormal fat metabolism, intramedullary adipocyte hypertrophy, and osteoporosis; however, the exact mechanism of SONFH is still not clearly understood. Animal models using rats, mice, rabbits, chickens, pigs, and emus have been used to study SONFH. Unfortunately, these models each have limitations. Therefore, it is necessary to establish a reproducible model that better simulates human disease. The present review is intended to summarize the currently available models, evaluative indicators, and application of current understanding to both the prevention and treatment of SONFH.

Steroid-associated osteonecrosis animal model in rats

OBJECTIVE

Established preclinical disease models are essential for not only studying aetiology and/or pathophysiology of the relevant diseases but more importantly also for testing prevention and/or treatment concept(s). The present study proposed and established a detailed induction and assessment protocol for a unique and cost-effective preclinical steroid-associated osteonecrosis (SAON) in rats with pulsed injections of lipopolysaccharide (LPS) and methylprednisolone (MPS).

METHODS

Sixteen 24-week-old male Sprague-Dawley rats were used to induce SAON by one intravenous injection of LPS (0.2 mg/kg) and three intraperitoneal injections of MPS (100 mg/kg) with a time interval of 24 hour, and then, MPS (40 mg/kg) was intraperitoneally injected three times a week from week 2 until sacrifice. Additional 12 rats were used as normal controls. Two and six weeks after induction, animals were scanned by metabolic dual energy X-ray absorptiometry for evaluation of tissue composition; serum was collected for bone turnover markers, Microfil perfusion was performed for angiography, the liver was collected for histopathology and bilateral femora and bilateral tibiae were collected for histological examination.

RESULTS

Three rats died after LPS injection, i.e., with 15.8% (3/19) mortality. Histological evaluation showed 100% incidence of SAON at week 2. Dual energy X-ray absorptiometry showed significantly higher fat percent and lower lean mass in SAON group at week 6. Micro-computed tomography (Micro-CT) showed significant bone degradation at proximal tibia 6 weeks after SAON induction. Angiography illustrated significantly less blood vessels in the proximal tibia and significantly more leakage particles in the distal tibia 2 weeks after SAON induction. Serum amino-terminal propeptide of type I collagen and osteocalcin were significantly lower at both 2 and 6 weeks after SAON induction, and serum carboxy-terminal telopeptide was significantly lower at 6 weeks after SAON induction. Histomorphometry revealed significantly lower osteoblast surface and higher marrow fat fraction and oedema area in SAON group. Hepatic oedema appeared 2 weeks after SAON induction, and lipid accumulation appeared in the liver of SAON rats 6 weeks after SAON induction.

CONCLUSION

The present study successfully induced SAON in rats with pulsed injection of LPS and MPS, which was well simulating the clinical feature and pathology. Apart from available large animal models, such as bipedal emus or quadrupedal rabbits, our current SAON small model in rats could be a cost-effective preclinical experimental model to study body metabolism, molecular mechanism of SAON and potential drugs developed for prevention or treatment of SAON.

THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE

The present study successfully induced SAON in a small animal model in rats with pulsed injection of LPS and MPS. The evaluation protocols with typical histopathologic ON features and advanced evaluation approaches to identify the metabolic disorders of SAON could be used in future rat SAON studies. The SAON rat model is a suitable and cost-effective animal model to study molecular mechanism of SAON and potential drugs developed for prevention and treatment of SAON.

Serum α-melanocyte-stimulating hormone may act as a protective biomarker for non-traumatic osteonecrosis of the femoral head

Background The α-melanocyte-stimulating hormone (α-MSH), an endogenous neuropeptide derived from proopiomelanocortin (POMC), has been identified to suppress inflammation and prevent osteoblast damage. Objective The present study was aimed to investigate the role of serum α-MSH in non-traumatic osteonecrosis of the femoral head (ONFH). Methods Seventy-nine patients diagnosed with non-traumatic ONFH and 79 sex- and age-matched healthy controls were enrolled in the study. Serum α-MSH concentrations were examined with a double antibody radioimmunoassay. The radiographic progression of ONFH was assessed by X-ray plain film according to the FICAT grading system. The symptomatic severity was evaluated by visual analogue scale scores, Harris hip scores and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores. The serum concentrations of protective marker adiponectin and bone necrosis inflammation factor IL-33 concentrations were also examined. The receiver operating characteristic (ROC) analysis curve was performed to explore the diagnostic value of α-MSH, adiponectin and IL-33 for radiographic progression. Results Serum α-MSH concentrations were significantly lower in ONFH patients than in healthy controls. The case group included 29 non-traumatic ONFH patients with FICAT grade I/II, 27 with grade III and 23 with grade IV. ONFH patients with grade I/II had significantly higher α-MSH concentrations in serum compared with those with FICAT grades III and IV. ONFH patients with FICAT grade III showed significantly elevated concentrations of α-MSH in serum compared with those with FICAT grade IV. Serum α-MSH concentrations were negatively associated with radiographic progression by FICAT grading system, and symptomatic severity defined by visual analogue scale scores, Harris hip scores and WOMAC scores. In addition, serum α-MSH concentrations were positively related to the expression of adiponectin and negatively associated with IL-33. ROC analysis curve demonstrated that α-MSH exhibited the equal value for the diagnosis of ONFH radiographic progression compared with IL-33. Conclusions Serum α-MSH may act as a protective biomarker for non-traumatic ONFH. Systematic application of α-MSH serving as an adjunctive therapy for treating non-traumatic ONFH deserves further investigation.

The protective effect of PFTα on alcohol-induced osteonecrosis of the femoral head

Epidemiologic studies have shown alcohol plays a pivotal role in the development of osteonecrosis of the femoral head (ONFH). The aim of this study was to explore the underlying mechanism of alcohol-induced ONFH and the protective effect of pifithrin-α (PFTα). In vitro, we found ethanol treatment significantly activated p53, suppressed Wnt/β-catenin signaling and inhibited osteogenic-related proteins. Furthermore, by separating the cytoplasmic and nuclear proteins, we found ethanol inhibited osteogenesis by impairing the accumulation of β-catenin in both the cytoplasm and nucleus in human bone mesenchymal stem cells (hBMSCs), which resulted from activating glycogen synthase kinase-3β (GSK-3β). Therefore, PFTα, a p53 inhibitor, was introduced in this study to block the ethanol-triggered activation of p53 in hBMSCs and alcohol-induced ONFH in a rat model. In vivo, we established alcohol-induced ONFH in rats and investigated the protective effect of PFTα. Hematoxylin & eosin (H&E) staining combined with TdT-mediated dUTP nick end labeling (TUNEL), cleaved caspase-3 immunohistochemical staining, and micro-CT images revealed substantial ONFH in the alcohol-administered rats, whereas significantly less osteonecrosis developed in the rats injected with PFTα. Osteogenic-related proteins, including osteocalcin, osteopontin and collagen I, were significantly decreased in the alcohol-administered rats, whereas these results were reversed in the PFTα-injected rats. Fluorochrome labeling similarly showed that alcohol significantly reduced the osteogenic activity in the rat femoral head, which was blocked by the injection of PFTα. In conclusion, PFTα had an antagonistic effect against the effects of ethanol on hBMSCs and could be a clinical strategy to prevent the development of alcohol-induced ONFH.

Substrain-specific differences in bone parameters, alpha-2-macroglobulin circulating levels, and osteonecrosis incidence in a rat model

Osteonecrosis of the femoral head (ONFH) is a potentially devastating complication that occurs in up to 40% of young adults receiving chronic glucocorticoid (GC) therapy. Through a validated GC therapy rat model, we have previously shown that Wistar Kyoto (WK) rats exhibit a genetic susceptibility to GC-induced ONFH compared to Sasco Fischer (F344) rats. We have undertaken this study in order to investigate differences between these two strains for their bone parameters, alpha-2-macroglobulin (A2M) circulating levels and incidence of GC-induced osteonecrosis of the femoral head. WK and F344 rats were treated either with 1.5 mg/kg/day of prednisone or placebo for 6 months. Blood was taken every month. The femoral heads were harvested for histological examination to detect ONFH and analyzed with micro-computed tomography. After 3 months of GC-therapy, plasma A2M was elevated in treated rats only. GC-treated WK rats exhibited histological evidence of early ONFH through higher rates of cellular apoptosis and empty osteocyte lacunae in the subchondral bone compared to placebos and to F344 rats. Furthermore, micro-CT analysis exhibited femoral head collapse only in GC-treated WK rats. Interestingly, GC-treated F344 rats exhibited significant micro-CT changes, but such changes were less concentrated in the articular region and were accompanied histologically with increased marrow fat. These µCT and histological findings suggest that elevated A2M serum level is not predictive and suitable as an indicative biomarker for early GC-induced ONFH in rodents. Elevated A2M levels observed during GC treatment suggests that it plays role in the host reparative response to GC-associated effects. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1183-1194, 2017.

Susceptibility of Males, but Not Females to Developing Femoral Head Osteonecrosis in Response to Alcohol Consumption

Background

We previously reported that ethanol-containing liquid diet feeding induces osteonecrosis of the femoral head in male rats. Also, it was reported that a large amount of consumed ethanol and a long-term history of drinking were risk factors for osteonecrosis of the femoral head, and that the frequency of alcohol-induced osteonecrosis of the femoral head in males was much greater than in females. The higher incidence of alcohol-induced osteonecrosis of the femoral head could be due to either higher prevalence of alcohol drinking in males or due to their potential higher sensitivity to alcohol. The aim of the study is to investigate the influence of alcohol consumption and drinking period on the development of osteonecrosis of the femoral head in rats of both sex.

Methods

All the experimental male rats were allocated to the male one-month ethanol drinking group (M1). Female rats were randomly divided into the female one- to five-months ethanol drinking groups (F1-5). All rats were fed a Lieber-DeCarli liquid diet containing 5% ethanol for one to five months.

Results

One-month feeding with the ethanol-containing liquid diet resulted in the development of osteonecrosis of the femoral head in seven of twenty in the M1 group, but none in the F1 group, although the mean intake of ethanol per body weight in the M1 group was significantly lower than that in the F1 group. Furthermore, long drinking periods with a large amount of ethanol intake in the F2-5 groups did not induce osteonecrosis of the femoral head.

Conclusion

The present study shows that lower alcohol consumption over short periods of time that were sufficient to induce osteonecrosis of the femoral head in males had no effect on females. Even with greater alcohol consumption and longer duration, females did not develop osteonecrosis of the femoral head. Therefore, unknown factors related to sex must be responsible for the development of this condition.