MnTBAP inhibits bone loss in ovariectomized rats by reducing mitochondrial oxidative stress in osteoblasts.

The development of postmenopausal osteoporosis is thought to be closely related to oxidative stress. Mn(III)tetrakis (4-benzoic acid) porphyrin (MnTBAP), a novel superoxide dismutase (SOD) mimetic, could protect osteoblasts from cytotoxicity and dysfunction caused by oxidative stress. However, it is still unclear whether MnTBAP has effect on the development of postmenopausal osteoporosis. Here, we demonstrated that MnTBAP can inhibit bone mass loss and bone microarchitecture alteration, and increase the number of osteoblasts while reducing osteoclasts number, as well as improve the BMP-2 expression level in ovariectomized rat model. Additionally, MnTBAP can also prevent oxidative stress status up-regulation induced by ovariotomy and hydrogen peroxide (H2O2). Furthermore, MnTBAP reduced the effect of oxidative stress on osteoblasts differentiation and increased BMP-2 expression levels with a dose-dependent manner, via reducing the levels of mitochondrial oxidative stress in osteoblasts. Taken together, our findings provide new insights that MnTBAP inhibits bone loss in ovariectomized rats by reducing mitochondrial oxidative stress in osteoblasts, and maybe a potential drug in postmenopausal osteoporosis therapy.

Modified dynamic hip screw loaded with autologous bone graft for treating Pauwels type-3 vertical femoral neck fractures.

INTRODUCTION: Management of Pauwels type-3 vertical femoral neck fractures has been a challenging clinical problem as they experience high shear forces and thus a greater risk of treatment failure. There is no apparent consensus on the optimal implant type for these injuries. We developed a modified dynamic hip screw (DHS), which was designed to a cage in the lag screw, loaded with autologous bone graft for the treatment of Pauwels type-3 vertical femoral neck fractures. METHODS: Between February 2010 and January 2012, 17 consecutive patients with Pauwels type-3 vertical femoral neck fractures were treated with the modified DHS loaded with autologous bone graft. All patients were followed up for a minimum of 24 months (range, 24-36 months). Surgical details, operative and postoperative complications, the rates of nonunion and osteonecrosis and the Harris hip score were evaluated. RESULTS: There were thirteen men and four women with a mean age of 37.2 years (range, 27-52 years). There were no intraoperative complications related to this technology. All fractures healed within 14.1 weeks (range, 12 to 20 weeks). One patient required total hip replacement because of avascular necrosis of the femoral head at 27 months after surgery. According to the Harris hip score, eleven patients (64.7%) had excellent results, four (23.5%) had good results, one (5.9%) had moderate and one (5.9%) had poor result. CONCLUSIONS: The modified DHS loaded with autologous bone graft appears to be a reliable implant for the treatment of Pauwels type-3 vertical femoral neck fractures with fewer complications.

Effect of Bone Cement Volume Fraction on Adjacent Vertebral Fractures After Unilateral Percutaneous Kyphoplasty.

STUDY DESIGN: A retrospective study. SUMMARY OF BACKGROUND DATA: Complications of the bone cement used in vertebroplasty and kyphoplasty procedures have received increasingly more attention, especially for bone cement volume. OBJECTIVE: The aim of the study was to retrospectively assess the relationship between bone cement volume fraction and adjacent vertebral fracture (AVF) after unilateral percutaneous kyphoplasty (PKP). MATERIALS AND METHODS: Between 2006 and 2011, 495 patients with single-level osteoporotic vertebral compression fracture (OVCF) were surgically treated by unilateral PKP and had completed 12-month follow-up in our hospital. According to the new OVCF, they were divided into 3 groups: AVF group, non-AVF group, and normal group (who were not new OVCF). On the basis of the value of the plain radiography, the cement volume fraction for the vertebral body was calculated, and cement leakage, bone mineral density, visual analog scale, and Cobb angle of preoperative and postoperative were analyzed. RESULTS: During the follow-up, 110 (22.2%) patients had new OVCF, and others were normal (n=385). Fifty-two cases were AVF and 58 were non-AVF. The cement volume fraction of AVF group, non-AVF group, and normal group were 32.5%±5.5%, 27.3%±1.8%, and 27.1%±2.6%, respectively. The 95% confidence interval of volume fraction were (31.0, 34.1), (26.8, 27.7), and (26.9, 28.5), respectively. The AVF group showed higher cement volume fraction in 3 groups (P<0.05), and there were no significant difference between non-AVF and normal group (P>0.05). There were 19 (36.5%) patients with cement leakage in AVF group, 12 (20.7%) in non-AVF group, and 68 (17.7%) in normal group. The AVF group showed higher cement leakage (P<0.05). Compared with AVF group and normal group, non-AVF group had lower bone mineral density in preoperation. All groups reported significantly improved visual analog scale scores and Cobb angle on the day of surgery. However, there were no significant difference between the 3 groups. CONCLUSIONS: Unilateral PKP is an effective and safe procedure for patients with OVCF. However, cement volume should be determined in terms of the vertebral body fraction to obtain a favorable outcome. The risk of AVF and cement leakage will increase obviously with the cement volume fraction increased. We recommend that a bone cement volume fraction of about one fourth is suitable for unilateral PKP.

Semirigid Waved Rod System for the Treatment of the Degenerative Lumbar Diseases.

BACKGROUND: The semirigid pedicle screw instrumentation has gained wide popularity in recent decennium in lumbar fusion surgery. However, few data were documented to compare the clinical efficacy between semirigid and traditional rigid pedicle screw systems. MATERIALS AND METHODS: A total of 96 patients with degenerative lumbar diseases were selected to perform operations between 2008 and 2013. The patients were prospectively randomized into 2 groups: 50 patients were managed by semirigid waved rod systems and 46 patients were intervened by traditional rigid straight stiff rod systems. X-rays and computed tomography were utilized to examine the interbody fusion status in the follow-up in detail. Surgical parameters such as operative time, blood loss, and total hospital stay were calculated and compared. Visual Analog Scale and Oswestry Disability Index were used to assess clinical efficacy postoperatively. RESULTS: No significant differences were found about demographic data between groups. There were no significant differences regarding the surgical parameters including operative time, blood loss, and total hospital stay. Visual Analog Scale and Oswestry Disability Index postoperatively were also similar between the 2 instrumentations (P>0.05). The fusion rate was higher in the semirigid group (45/50) than in the traditional group (34/46) (P=0.039) at the final follow-up. CONCLUSIONS: Waved rod may be better in facilitating interbody fusion compared with traditional straight rod, although waved rod and straight stiff rod can both get similar clinical efficacy. Meanwhile, waved rod is likely superior in alleviating adjacent degeneration segments.

Bone fracture in a rat femoral fracture model is associated with the activation of autophagy.

Autophagy, which is a mechanism for the turnover of intracellular molecules and organelles, protects cells during stress responses; however, the role of autophagy in the stages of bone fracture remains to be elucidated. The aim of the present study was to investigate the process of autophagy in bone tissue at different time-points after fracture. A femur fracture model was established in male adult Wistar rats via surgery. The protein expression of microtubule-associated protein II light chain 3 (LC3-II) was analyzed in a femur fracture (experimental) group and a sham-surgery group using immunofluorescence. The protein expression of proliferating cell nuclear antigen (PCNA) was used to investigate the cell proliferation in bone tissue following fracture via immunohistochemical analysis. The correlation between cell proliferation and autophagy was analyzed using linear regression. LC3-II protein was constitutively expressed in the sham-surgery group; however, compared with the expression in the sham-surgery group, the LC3-II expression in the experimental group was significantly increased at each time-point (P<0.05). Similarly, immunohistochemistry revealed that the number of PCNA-positive cells in each section was significantly increased following fracture injury (P<0.01). A comparison of the LC3-II- and PCNA-positive rates in the experimental group rats at each time-point revealed a linear correlation (R2=0.43, P<0.01). In conclusion, surgically induced fracture in rats is associated with an increase in LC3-II and PCNA protein expression during the initial stages of fracture injury, and a correlation exists between the expression of the two proteins. These results suggest that potential treatment aimed at improving fracture healing should target the process of autophagy.