Diosmetin inhibits subchondral bone loss and indirectly protects cartilage in a surgically-induced osteoarthritis mouse model.

Osteoarthritis (OA) is a common degenerative disease characterized by articular cartilage destruction, subchondral bone remodeling, ectopic osteophyte formation and synovitis. It is now recognized that the integrity of the underlying subchondral bone is crucial for the maintenance of the overlying articular cartilage. Therapeutic agents that can prevent subchondral bone loss are demonstrate potential in the prevention and treatment of OA. Diosmetin (DIOS; 3',5,7 -trihydroxy-4'-methoxy flavone), a natural flavonoid, has been shown to exert anti-oxidative, anti-inflammatory, anti-apoptotic and anticancer properties. In this study, we found that diosmetin suppressed the DMM-induced subchondral bone loss and reduced subsequent cartilage degradation in vivo. Cellular-based assays showed that diosmetin inhibited RANKL-induced osteoclast formation and bone resorption,but did not affect IL-1ß-induced chondrocyte hypertrophy. Biochemical analyses demonstrated that the anti-osteoclastic effect of diosmetin was at least in part due to the suppression of RANKL-induced activation of the ERK, p38, and JNK MAPK signaling pathways. Collectively, our results show that diosmetin have potential as a therapeutic agent the treatment of abnormal subchondral bone loss and cartilage degradation associated with the onset of OA.

Nicorandil Inhibits Osteoclast Formation Base on NF-κB and p-38 MAPK Signaling Pathways and Relieves Ovariectomy-Induced Bone Loss.

Osteolytic bone disorders are characterized by an overall reduction in bone mineral density which enhances bone ductility and vulnerability to fractures. This disorder is primarily associated with superabundant osteoclast formation and bone resorption activity. Nicorandil (NIC) is a vasodilatory anti-anginal drug with ATP-dependent potassium (KATP) channel openings. However, NIC is adopted to manage adverse cardiovascular and coronary events. Recent research has demonstrated that NIC also possesses anti-inflammatory peculiarity through the regulation of p38 MAPK and NF-κB signaling pathways. Both MAPK and NF-κB signaling pathways play pivotal roles in RANKL-induced osteoclast formation and bone resorption function. Herein, we hypothesized that NIC may exert potential biological effects against osteoclasts, and revealed that NIC dose-dependently suppressed bone marrow macrophage (BMM) precursors to differentiate into TRAP + multinucleated osteoclasts in vitro. Furthermore, osteoclast resorption assays demonstrated anti-resorptive effects exhibited by NIC. NIC had no impact on osteoblast differentiation or mineralization function. Based on Biochemical analyses, NIC relieved RANKL-induced ERK, NF-κB and p38 MAPK signaling without noticeable effects on JNK MAPK activation. However, the attenuation of NF-κB and p38 MAPK activation was sufficient to hamper the downstream induction of c-Fos and NFATc1 expression. Meanwhile, NIC administration markedly protected mice from ovariectomy (OVX)-induced bone loss through in vivo inhibition of osteoclast formation and bone resorption activity. Collectively, this work demonstrated the potential of NIC in the management of osteolytic bone disorders mediated by osteoclasts.

Surface defective g-C3N4-xClx with unique spongy structure by polarization effect for enhanced photocatalytic removal of organic pollutants.

Natural sponge is an ancient marine organism with a single lamellar structure, on which there are abundant porous channels to compose full-fledged spatial veins. Illumined by the natural spongy system, herein, the Cl doped surface defective graphite carbon nitride (g-C3N4-xClx) was constructed through microwave etching. In this process, microwave with HCl was employed to produce surface defects and peel bulk g-C3N4 to form natural spongy structured g-C3N4-xClx with three-dimensional networks. The spongy structure of the photocatalyst could provide abundant and unobstructed pathways for the transfer and separation of electron-hole pairs, and it was beneficial for photocatalytic reaction. The spongy defective g-C3N4-xClx achieved excellent degradation of diclofenac sodium (100%), bisphenol A (88.2%), phenol (85.7%) and methylene blue (97%) solution under simulated solar irradiation, respectively. The chlorine atoms were introduced into the g-C3N4 skeleton in microwave field with HCl, forming C-Cl bonds and surface polarization field, which could significantly accelerate the separation of photogenerated electrons and holes. As an efficient and universal approach, microwave etching can be generally used to create surface defects for most photocatalysts, which may have potential applications in environmental purification, energy conversion and photodynamic therapy.

[BIOMECHANICS STUDY ON ACETABULAR POSTERIOR WALL FRACTURE].

OBJECTIVE: To study the experimental biomechanics of acetabular posterior wall fractures so as to provide theoretical basis for its clinical treatment. METHODS: Six formalin-preserved cadaveric pelvises were divided into groups A and B (n=3). The fracture models of superior-posterior wall and inferior-posterior wall of the acetabulum were created on both hips in group A; fractures were fixed with two interfragmentary screws and a locking reconstruction plate. The fracture models of superior-posterior wall of acetabulum were created on both hips in group B; fractures were fixed with two interfragmentary screws and a locking reconstruction plate at one side, and with acetabular tridimensional memory fixation system (ATMFS) at the other side. The biomechanical testing machine was used to load to 1 500 N at 10 mm/min speed for 30 seconds. The displacement of superior and inferior fracture sites was analyzed with the digital image correlation technology. RESULTS: No fracture or internal fixation breakage occurred during loading and measuring; the displacement valuess of the upper and lower fracture lines were below 2 mm (the clinically tolerable maximum value) in 2 groups. In group A, the displacement values of the upper and lower fracture lines at superior-posterior wall fracture site were significantly higher than those at inferior-posterior wall fracture site (P < 0.01), and the displacement values of the upper fracture line were significantly higher than those of lower fracture line (P < 0.01) in two fracture types. In group B, the displacement values of the upper and lower fracture lines at the side fixed with screws and a locking reconstruction plate were similar to the values at the side fixed with ATMFS, all being close to 2 mm; the displacement values of the upper fracture line were significantly higher than those of lower fracture line (P < 0.05) in two fixation types. CONCLUSION: The actual biomechanical effect of the superior-posterior wall of acetabulum is much greater than that of the inferior-posterior wall of acetabulum and they should be discriminated, which might be the reasons of reduction loss, femoral head subluxation, and traumatic arthritis during follow-up.

Captopril, an angiotensin-converting enzyme inhibitor, possesses chondroprotective efficacy in a rat model of osteoarthritis through suppression local renin-angiotensin system.

OBJECTIVE: A local tissue-specific renin-angiotensin system (local RAS) has emerged as a regulator of cartilage development and homeostasis. However, no report has described the chondroprotective efficacy of RAS inhibitor. Therefore, we studied the pharmacological function of captopril on hypertrophic differentiation of chondrocytes, cartilaginous degeneration and RAS components expression in a rat model of osteoarthritis (OA). METHODS: OA was surgically induced in the right knee of male rats. Animal groups included age matched sham control (sham group), OA placebo (OA group), and OA treated with captopril (CAP group). Eight weeks after the induction of OA, the tibias were isolated and the sagittal sections were stained with Safranin O and Masson-Trichrome. The mRNA and protein expression of RAS components were measured by qRT-PCR and western blotting respectively. RESULTS: The thickness of articular cartilage was reduced in the proximal tibia of the OA group, and decreased thickness of articular cartilage of the OA mice was effectively reversed by captopril treatment. Histological analyses revealed remarkable chondrocytes abnormality in OA rats, which were characterized by a marked expansion of hypertrophic zone and inhibition of proliferative zone of chondrocytes in the epiphyseal growth plate of tibia. However, captopril-treated could reverse chondrocytes abnormality in OA rats. Furthermore, the mRNA and protein expression of RAS components, renin, ACE, Ang II AT1R were upregulated in the proximal tibia of OA rats, however, the AT2R expression was suppressed. Intriguingly, captopril-treated could inhibit the activation of RAS in OA rats. CONCLUSIONS: The present study demonstrated that captopril could attenuate OA-induced osteoarticular injury, at least partially, through suppression local RAS.

Management of Postoperative Spondylodiscitis with and without Internal Fixation.

Postoperative spondylodiscitis is relatively uncommon. This complication is associated with increased cost, and long-term of inability to work, and even morbidity. Although the majority of postoperative spondylodiscitis cases can be well managed by conservative treatment, postoperative spondylodiscitis after internal fixation and those cases that are unresponsive to the conservative treatment present challenges to the surgeon. Here, a review was done to analyze the treatment of postoperative spondylodiscitis with/without internal fixation. This review article suggested that majority of postoperative spondylodiscitis without internal fixation could be cured by conservative treatment. Either posterior or anterior debridement can be used to treat postoperative spondylodiscitis without internal fixation when conservative treatment fails. In addition, minimally invasive debridement and drainage may also be an alternative treatment. In case of postoperative spondylodiscitis after internal fixation, surgical treatment was required. In the cervical spine, it can be well managed by anterior debridement, removal of internal fixation, and reconstruction of the spinal stability by using bone grafting/cage/anterior plate. Postoperative spondylodiscitis after internal fixation is successfully managed by combined anterior debridement, fusion with posterior approach and removal of pedicle screw or extension of pedicle screw beyond the lesion site, in the thoracic and lumbar spine.

Transforming growth factor-ß1 induces type II collagen and aggrecan expression via activation of extracellular signal-regulated kinase 1/2 and Smad2/3 signaling pathways.

Transforming growth factor (TGF)­ß regulates the anabolic metabolism of articular cartilage and prevents cartilage degradation. TGF­ß1 influences cellular proliferation, differentiation and the extracellular matrix through activation of the extracellular signal­regulated kinase (ERK)1/2 and Smad2/3 signaling pathways. However, it has remained to be fully elucidated precisely how the ERK1/2 and Smad2/3 signaling pathways mediate anabolic processes of articular cartilage. The present study investigated how ERK1/2 and Smad2/3 signaling mediate TGF­ß1­stimulated type II collagen and aggrecan expression in rat chondrocytes. The results confirmed that TGF­ß1 stimulates type II collagen and aggrecan expression in rat chondrocytes, and furthermore, that the ERK1/2 and Smad2/3 signaling pathways were activated by TGF­ß1. Conversely, the TGF­ß receptor I (ALK5) kinase inhibitor SB525334 significantly impaired TGF­ß1­induced type II collagen and aggrecan expression, coinciding with a reduction of ERK1/2 and Smad3 phosphorylation. In addition, TGF­ß1­induced type II collagen and aggrecan expression were significantly suppressed by ERK1/2 inhibitor PD98059. Similarly, TGF­ß1­stimulated type II collagen and aggrecan expression were decreased in the presence of a Smad3 phosphorylation inhibitor SIS3. Therefore, the present study demonstrated that the ERK1/2 and Smad2/3 signaling pathways regulate type II collagen and aggrecan expression in rat chondrocytes.

Interaction of ERK1/2 and Smad2/3 signaling pathways in TGF-ß1-induced TIMP-3 expression in rat chondrocytes.

Tissue inhibitor of metalloproteinase-3 (TIMP-3) is an important natural inhibitor of matrix metalloproteinases (MMPs) and of a disintegrin and metalloproteinase with thrombospondin motif (ADAMTs), which can cleave cartilage extracellular matrix components to cause cartilage degradation. In this study, our data suggest TGF-ß1 induces TIMP-3 expression through activations of both the ERK1/2 and Smad2/3 signaling pathways. TGF-ß1-stimulated TIMP-3 expression was significantly inhibited by SB525334 (TGF-ß receptor I kinase inhibitor), accompanied by a reduction in ERK1/2 and Smad3 phosphorylation. We used PD98059 (MEK inhibitor) and SIS3 (inhibitor of Smad3 phosphorylation) to investigate the respective roles of ERK1/2 and Smad2/3 signaling pathways in TGF-ß1-induced TIMP-3 expression. The results show PD98059 treatment significantly suppressed TGF-ß1-induced ERK1/2 phosphorylation and TIMP-3 expression. Under these conditions, the degree of Smad3 phosphorylation correlated with ERK1/2 activation, which suggests that ERK1/2 may activate Smad3 phosphorylation. SIS3 significantly inhibited TGF-ß1-induced Smad3 phosphorylation and TIMP-3 expression. ERK1/2 phosphorylation alone had no effect on TGF-ß1-induced TIMP-3 expression, which suggests ERK1/2 via Smad3 phosphorylation regulates TGF-ß1-induced TIMP-3 expression. Here, we demonstrate that ERK1/2 may be capable of activating the Smad2/3 signaling pathway to result in TGF-ß1-induced TIMP-3 up-regulation.

Osthole inhibits proliferation and induces apoptosis in human osteosarcoma cells.

OBJECTIVE: The purpose of this study was to investigate the effect of osthole on osteosarcoma cell proliferation and apoptosis. METHOD: Cell counting Kit-8 assay was performed to establish the effects of osthole on osteosarcoma MG-63 cell proliferation. Annexin V-FITC/PI was performed to analyze the apoptotic rate of the cells. RESULT: The inhibitory effects of osthole on the expression of BCL-2, BAX, and caspase-3 were detected by Western blotting. Osthole inhibited the growth of human osteosarcoma MG-63 cells by inhibiting cell proliferation and induced cell apoptosis. Western blotting demonstrated that osthole downregulated the expressions of BCL-2 and caspase-3 and upregulated the expression of BAX in human osteosarcoma cells. CONCLUSION: Osthole can inhibit osteosarcoma cell proliferation and induced apoptosis effectively in a dose-dependent manner through downregulating the expression of BCL-2 and caspase-3 proteins levels and upregulating the expression of BAX proteins levels.

[Anatomic measurements and quantitative analysis of posterior acetabular wall].

OBJECTIVE: To explore morphological character and clinical significance of superior-posterior acetabular wall by anatomically measuring and quantitatively analyzing thickness of posterior acetabular wall, then provide a theoretical reference for clinical treatment of acetabular fracture. METHODS: Fifteen adult formalin-preserved cadaveric pelvises (8 males and 7 females) were used for this investigation. Excess soft tissue was removed and the whole acetabular posterior walls were marked with "angle" sector method and the thickness was measured with caliper in different levels of the different split points. The measurement results were validated and analyzed statistically. RESULTS: At 5 mm away from acetabular rim, the average thickness of superior-posterior acetablar wall fluctuated between (6.47±0.61) mm and (7.43±0.71) mm; the average thickness of inferior-posterior acetabuluar wall fluctuated between (5.62±0.51) mm and (6.33±0.61) mm; the average thickness of acetabular roof fluctuated between (7.71±0.74) mm and (8.27±0.99) mm. There was no statistical difference between average thickness of superior-posterior wall of acetabulum and inferior-posterior wall of acetabulum (P>0.05), but the average thickness of acetabular roof was significantly larger than superior-posterior acetabular wall (P<0.05). At 10 mm away from the acetabular rim, the average thickness of superior-posterior acetabular wall fluctuated between (8.81±0.67) mm and (13.35±0.89)mm; the average thickness of inferior-posterior acetabular wall fluctuated between (7.02±0.63) mm and (7.66±0.69) mm; the average thickness of acetabular roof fluctuated between (14.46±0.97) mm and (17.05±1.35) mm. Comparatively, the average thickness of superior-posterior acetabular wall was significantly larger than inferior-posterior wall of acetabulum (P<0.05), and the average thickness of acetabular roof was significantly larger than superior-posterior acetabular wall (P<0.01). At 15 mm away from the acetabular rim, the average thickness of superior-posterior acetabular wall fluctuated between (12.08±0.78) mm and (19.84±1.03) mm; the average thickness of inferior-posterior acetabular wall fluctuated between (10.17±0.76) mm and (11.12± 0.77) mm; the average thickness of acetabular roof fluctuated between (23.23±1.12) mm and (26.01±1.53) mm. Comparatively, the average thickness of superior-posterior wall of acetabulum was significantly larger than inferior-posterior acetabular wall (P<0.01), and the average thickness of acetabular roof was significantly larger than superior-posterior acetabular wall (P< 0.01). CONCLUSION: The thickness of entire acetabular posterior edge revealed an increasing tendency from inferior-posterior wall to the superior-posterior wall to acetabular roof. And this trend became more obvious with increasing distance away from acetabular rim. Therefore, the superior-posterior acetabular wall could not only maintain the stability of hip joint but also bear loading.

Reduction and fixation of the avulsion fracture of the tibial eminence using mini-open technique.

The purpose of this prospective study is to present and evaluate a new technique using suture anchors for the treatment of the avulsion fractures of the tibial eminence. Twenty-three consecutive patients with the displaced avulsion fracture of the tibial attachment of anterior cruciate ligament were treated using mini-open technique with suture anchors between 2005 and 2008. According to the classification of Meyers and McKeever, there were 5 type II, 13 type III, and 5 type IV fractures. The median follow-up period was 18 months (range, 12-32 months). The patient assessment included Lysholm score, Tegner score, IKDC score, and radiographic evaluation. The median Lysholm score improved from 32 (range, 28-48) preoperatively to 98 (range, 85-100) postoperatively. The median preoperative Tegner score was 3 (range, 2-5), and the median postoperative Tegner score was 7 (range, 5-9). The global IKDC objective score was normal (A) in 21 knees and nearly normal (B) in 2 knees. At final follow-up, the Lachman test and anterior drawer test were negative. The results showed that mini-open reduction and fixation of avulsion fracture of the tibial eminence with suture anchors have achieved satisfactory results. We suggest the use of this technique for treating avulsion fractures of the tibial eminence.

Long-term outcomes after deltoid muscular flap transfer for irreparable rotator cuff tears.

We reviewed 20 cases (18 patients) with massive, irreparable rotator cuff tears that were treated with a deltoid flap transfer. The mean follow-up was 13.9 years. The mean absolute Constant score increased from 49.1 points preoperatively to 71.9 points at the last follow-up (P < .001). Pain scores improved from 5.3 to 13.8 points, regardless of the state of the deltoid flap (P < .001), and the scores for activities of daily living increased from 8.6 to 17 points (P < .001). The mean muscular strength improved from 4.4 points preoperatively to 7.6 points at the last follow-up (P = .009), and 16 patients (80%) had a positive test for supraspinatus strength. Deltoid flaps were completely ruptured in 3 cases in the short term and 10 cases at later follow-up; the mean thickness of nonruptured deltoid flaps was 4.2 mm. The mean acromiohumeral distance decreased from 6.95 mm preoperatively to 3.05 mm postoperatively (P < .00001). Osteoarthritis rates increased from stage 0.6 to stage 2.0 by the classification of Samilson and Prieto (P < .0001). This study shows that the results of a deltoid flap transfer over short- or medium-term follow-up were satisfactory for individuals who wished to return to work or for pain relief, with an improvement in the total function of the shoulder. However, the long-term outcomes were poor; deltoid flaps were ruptured in 10 shoulders (50%), and stage 2 or 3 osteoarthritis occurred in 14 shoulders (70%). Therefore, we do not recommend further use of this procedure in the treatment of massive, irreparable rotator cuff tears.