acid-phosphatase and Osteonecrosis

Osteonecrosis of the femoral head is frequently observed in patients treated with excessive corticosteroids. However, the pathogenesis of corticosteroid-induced osteonecrosis remains unclear. The purpose of this study was to investigate the role of Toll-like receptor 4 (TLR4) signaling pathway in steroid-induced femoral head osteonecrosis in rats. Male Sprague-Dawley rats were injected intramuscularly with 20 mg/kg methylprednisolone (MP) for 8 weeks, twice per week. The animals were sacrificed at 2, 4 and 8 weeks after the last MP injection, respectively, and then allocated to the 2-, 4- and 8-week model groups (n=24 each). Rats in the control group (n=12) were not given any treatment. Histopathological analysis was performed and the concentration of tartrate-resistant acid phosphatase (TRAP) in plasma was determined. The activation of osteoclasts in the femoral head was assessed by TRAP staining. The expression of TLR4, MyD88, TRAF6 and NF-κB p65 that are involved in TLR4 signaling, and MCP-1 production were detected by using real-time PCR (RT-PCR) and Western blotting. The results showed that the osteonecrosis in the femoral head was clearly observed and the concentration of TRAP in the plasma was increased in the model rats. The femoral head tissues in MP-treated rats were positive for TRAP and the intensity of TRAP staining was greater in MP-treated rats than in control rats. As compared with the control group, the mRNA expression of TLR4 signaling-related factors was enhanced significantly at 4 and 8 weeks, and the protein levels of these factors increased significantly with time. It was concluded that MP could induce the femoral head osteonecrosis in rats, which was associated with osteoclast activation via the TLR4 signaling pathway. These findings suggest that TLR4 signaling pathway plays a pivotal role in the pathogenesis of steroid-induced osteonecrosis.

Topics: Acid Phosphatase; Animals; Blotting, Western; Chemokine CCL2; Femur Head; Gene Expression; Immunohistochemistry; Isoenzymes; Male; Methylprednisolone; Myeloid Differentiation Factor 88; Osteonecrosis; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Tartrate-Resistant Acid Phosphatase; Time Factors; TNF Receptor-Associated Factor 6; Toll-Like Receptor 4; Transcription Factor RelA

Osteonecrosis is also known as avascular necrosis, and two types of cell death are included in the pathogenesis of osteonecrosis: necrosis and apoptosis. Apoptosis in the osteonecrosis of femoral head is thought to be the key determinant of glucocorticoid-induced cortical bone loss. The present study was implemented to evaluate the anti-apoptotic effect of Granulocyte colony-stimulating factor and stem cell factor (G-CSF/SCF) in rabbits with steroid-induced osteonecrosis.. In the experiment, osteonecrosis was induced by low-dose lipopolysaccharide and subsequent pulsed high-dose methylprednisolone. Rabbits in preventive medicine group were treated with 100 μg/kg/d G-CSF and 25 μg/kg/d SCF. Then hematological and histomorphometric methods were used to investigate the treatment effects of osteonecrosis. Apoptosis was assessed via quantitative TUNEL staining and activated caspase-3 immunostaining and immunoblotting.. The results showed that G-CSF/SCF treatment could increase the secretion of serum osteocalcin, but inhibit the expression of serum tartrate-resistant acid phosphatase (TRAP5b). The incidence of osteonecrosis was significantly decreased in Preventive group when compared with Steroid group (42.1% vs. 88.2%). Histomorphometric analysis showed that G-CSF/SCF pre-disposal treatment was able to increase trabecular mineral appositional rate (MAR) and bone formation rate (BFR). Quantitative TUNEL and activated caspase-3 levels showed lower apoptosis in the Preventive group.. In conclusion, G-CSF/SCF treatment could inhibit caspase-3-dependent apoptosis in osteocytes to exert beneficial effects in preventing steroid-induced ON in rabbit models.

Topics: Acid Phosphatase; Animals; Apoptosis; Caspase 3; Granulocyte Colony-Stimulating Factor; Isoenzymes; Methylprednisolone; Osteocalcin; Osteogenesis; Osteonecrosis; Rabbits; Stem Cell Factor; Tartrate-Resistant Acid Phosphatase

This study investigated 51 patients with Type 1 Gaucher's disease clinically and radiographically for the presence of osteonecrosis. Twenty-five female and 26 male patients with a mean age of 37 years were evaluated retrospectively for osteonecrosis of the proximal and distal femur, proximal tibia, and proximal humerus. All patients were examined before enzyme replacement therapy. Gender, age at diagnosis, prior splenectomy, hematocrit, platelet count, acid phosphatase level, radiographs of the long bones, and magnetic resonance quantitative chemical shift imaging of the spine were analyzed to see if any of these values or findings were associated with the presence of osteonecrosis. Splenectomy was an independent risk factor for the presence of osteonecrosis in three of the four major sites and was a multivariate risk factor for osteonecrosis of the proximal femur and tibia. Male gender was the other significant multivariate risk factor for osteonecrosis of the humerus and distal femur when all sites were taken into account.

Topics: Acid Phosphatase; Adult; Age Factors; Confidence Intervals; Female; Femur; Femur Head Necrosis; Gaucher Disease; Hematocrit; Humans; Humerus; Lumbar Vertebrae; Magnetic Resonance Spectroscopy; Male; Multivariate Analysis; Odds Ratio; Osteonecrosis; Platelet Count; Radiography; Retrospective Studies; Risk Factors; Sex Factors; Splenectomy; Tibia