ObjectiveTo investigate the effect of Staphylococcal peptidoglycan (PGN-sa) on raw264.7 cells differentiating into osteoclasts. MethodsThere were 5 groups in the experiment: 100 ng/mL PGN-sa group, 200 ng/mL PGN-sa group, 400 ng/mL PGN-sa group, positive control group [100 ng/mL receptor activator of nuclear factor κB ligand (RANKL)], and blank control group (PBS). Raw264.7 cells were cultured with different concentrations of PGN-sa, RANKL, or PBS for 5 days, and then tartrate resistant acid phosphatase (TRAP) staining was used to detect the formation of osteoclast-like cells; Image-Pro Plus 6.0 software was used to detect the bone resorption areas of osteoclast-like cells; and MTT assay was used to observe the proliferation activity of raw264.7 cells. ResultsTRAP staining showed that PGN-sa and RANKL can induce raw264.7 cells to differentiate into osteoclast-like cells; different concentrations of PGNsa groups had more osteoclast-like cells formation than blank control group (P < 0.05), and the number of osteoclast-like cells significantly increased with the increase of PGN-sa concentrations (P < 0.05). Bone resorption cavity experiment showed that bone resorption cavities were obvious in different concentrations of PGN-sa groups and in positive control group, and the area of bone absorption cavities was increased with the increasing PGN-sa concentrations, showing significant difference between groups (P < 0.05). MTT assay showed that no significant difference was found in the absorbance (A) value between different concentrations of PGN-sa groups and blank control group, and between different concentrations of PGN-sa groups (P > 0.05). ConclusionPGN-sa can promote raw264.7 cells to differentiate into osteoclasts with bone resorption activity.
Objective To compare the bone resorption between the proximal fixation of the anatomique benoist giraud（ABG） hip and the distal fixation of the anatomic medullary locking（AML） hip by the medium-term X-ray films, and to evaluate the clinical results of the two prostheses. Methods From January 1992 to December 1996, 298 patients (396 hips) underwent the total hip arthroplasty at Wilson Hospital in Korea. In 125 patients, 176 hips were ABG hips, including 103 avascularnecrosis hips, 57 dysplasia hips, and 16 other diseased hips; In the other 173 patient the remaining 220 hips were AML hips, including 147 avascular necrosis hips, 65 dysplasia hips, and 8 other diseased hips. The A-P X-ray imagings were followed up for 5-12 years averaged 8 years, and were compared with the immediate postoperative X-ray imagings. The bone resorption area was measured and the bone resorption cases were recorded according to the Gruen zone obsesvation. Results During operation, 2 ABG hips and 5 AML hips were cracked at the femoral diaphysis; 3 ABG hips and 1 AML hip were cracked at the metaphysis; 6 ABGhips and 3 AML hips were fractured because of trauma after operation; among them, 2 ABG hips needed the stem revision and the remaining hips underwent the openreduction and the internal fixation. During the follow-up, 9 ABG hips were revised, 7 hips of which developed the aseptic loosening. No AML hip was revised, but 3 AML hips developed the aseptic loosening. The bone resorption pattern in theABG and AML hips was similar. The bone resorption occurred most commonly in theGruen zones 1 and 7, and it extended from the metaphysis to the diaphysis. In the Guren zones 2, 5, 6 and 7, there were more AML hips than ABG hips that developed the bone resorption. The bone resorption area around the AML hip was larger than that around the ABG hip. Conclusion The stress shielding bone resorption usually occurs proximally to the union area of the bone and the prosthesis. The ABG prosthesis is a proximal fixation prosthesis, therefore, the stress shielding bone resorption can be reduced. The bone resorption around the AML prosthesis develops slowly within 10 years after operation. The stress shielding bone resoption may reach the summit within 10 years and it will not develop endlessly, so the prosthesis will be stable for a long time. The probabilityof the bone resorption in the ABG prosthesis is smaller than that in the AMLprosthesis. The bone resorption around the AML prosthesis may develop slowly after 10 years and will not affect the stability of the prosthesis for a long time.
This study aims to investigate the therapeutic efficacy of 50 Hz-0.6 mT low-frequency pulsed electromagnetic field (PEMF) on postmenopausal osteoporosis in ovariectomized rats. Thirty 3-month-old female SD rats were selected and divided into a sham operation group (Sham), an ovariectomized model group (OVX), and a low-frequency pulsed electromagnetic field (PEMF) treatment group, with 10 rats in each group. After 8 weeks, the whole-body bone mineral density (BMD) of each group of rats was measured. The treatment group began to receive PEMF stimulation for 90 minutes daily, while the OVX group only received a simulated placement without electricity. After 6 weeks of intervention, all rats were sacrificed and tested for in vitro BMD, micro-CT, biomechanics, serum biochemical indicators, and bone tissue-related proteins. The results showed that the BMD of the OVX group was significantly lower than that of the Sham group 8 weeks after surgery, indicating successful modeling. After 6 weeks of treatment, compared with the OVX group, the PEMF group exhibited significantly increased BMD in the whole body, femur, and vertebral bodies. Micro-CT analysis results showed improved bone microstructure, significantly increased maximum load and bending strength of the femur, elevated levels of serum bone formation markers, and increased expression of osteogenic-related proteins. In conclusion, this study demonstrates that daily 90-minute exposure to 50 Hz-0.6 mT PEMF effectively enhances BMD, improves bone biomechanical properties, optimizes bone microstructure, stimulates bone formation, and inhibits bone resorption in ovariectomized rats, highlighting its therapeutic potential for postmenopausal osteoporosis.