Effect of different orientations of screw fixation for radial head fractures: a biomechanical comparison.

BACKGROUND: Screw fixation is a common method used for the treatment of Mason type II radial head fractures. The purpose of our study was to evaluate the mechanical properties of three different screw orientations used for fixation of Mason type II radial head fractures. METHODS: We sawed 24 medium-frequency fourth-generation Synbone radial bones to simulate unstable radial head fractures, which we then fixed with three different screw orientations. Implants were tested under axial load by the tension-torsion composite test system. If the implant-radial constructs did not fail after the axial load test, an axial failure load was added to the remaining constructs. RESULTS: The stiffness of the divergent group was the highest of the three orientations, and this group had statistically significant difference from the other two groups (p < 0.05). However, there was no statistically significant difference between the convergence group and the parallel group (p > 0.05). When the displacement reached 2 mm, the load of the divergent screw was still larger than the other two groups (p < 0.05). CONCLUSIONS: The divergent screw orientation was the most stable and had the greatest control of Mason type II fractures of these three groups. Therefore, it can be better applied in clinical settings.

Alpha-Mangostin suppresses interleukin-1ß-induced apoptosis in rat chondrocytes by inhibiting the NF-κB signaling pathway and delays the progression of osteoarthritis in a rat model.

Osteoarthritis (OA) is a chronic degenerative joint disease that is characterized by progressive joint dysfunction and pain. Apoptosis and catabolism in chondrocytes play critical roles in the development of OA. Alpha-Mangostin (α-MG), one of the main components of the mangosteen, has been reported to have anti-apoptotic, anti-inflammatory and antioxidant effects. We investigated the therapeutic effects of α-MG on OA through experiments on rat chondrocytes in vitro and in a rat model of OA induced by destabilization of the medial meniscus (DMM). In vitro, we provided experimental evidence that α-MG inhibits the expression of MMP-13 and ADAMTs-5, and promotes the expression of SOX-9 in rat chondrocytes stimulated with interleukin-1ß (IL-1ß). In addition, we also found that α-MG can inhibit the expression of pro-apoptotic proteins such as Bax, Cyto-c, and C-caspase3, and increase the expression of the anti-apoptotic protein Bcl-2. These changes may be related to an α-MG induced inhibition of the IL-1ß-induced activation of the NF-kB signaling pathway. In vivo, we also found that α-MG can limit the development of OA in rat models. The above results show that α-MG has a potential therapeutic effect on OA, and that this effect may be achieved by inhibiting the mitochondrial apoptosis of chondrocytes induced by an activation of the NF-kB pathway.

Alpha-Mangostin protects rat articular chondrocytes against IL-1ß-induced inflammation and slows the progression of osteoarthritis in a rat model.

Osteoarthritis (OA) is a joint disease characterized by inflammation and cartilage degradation. α-Mangostin (α-MG), which can be isolated from the fruit of the tropical evergreen tree Garcinia mangostana-L, is known to have anti-inflammatory properties. The aim of the study was to investigate the use of α-MG in the treatment of OA, using both rat chondrocytes and an OA rat model induced by destabilization of the medial meniscus (DMM). Rat chondrocytes were pretreated with α-MG (0, 1.25, 2.5, and 5.0µg/ml for 24h) prior to stimulation with interleukin-1ß (IL-1ß) (10ng/ml for 24h). Nitric oxide (NO) production was determined using the Griess method and prostaglandin E2 (PGE2) was assessed using an enzyme-linked immunosorbent assay (ELISA). The expression of inducible nitric oxide synthase (INOS), cyclooxygenase-2 (COX-2), matrix metalloproteinase-3, -9, and -13 (MMP-3, MMP-9, and MMP-13), Collagen II, and Aggrecan were detected by both quantitative real-time PCR (qRT-PCR) and a western blot analysis. Nuclear factor-κB (NF-κB) signaling molecules were detected by western blot analysis. Detection of p65 nuclear translocation of NF-κB was examined using immunofluorescence staining. The OA rats received intraperitoneal injections of α-MG (10mg/kg) or saline every other day. Hematoxylin and eosin and Safranin-O-Fast green staining were used to evaluate the severity of cartilage lesions up to 8weeks following surgery. α-MG inhibited the production of NO and PGE2. The elevated expression of INOS, COX-2, MMP-3, MMP-9, and MMP-13, and the degradation of Collagen II and Aggrecan, were reversed by α-MG in IL-1ß-stimulated chondrocytes. In addition, IL-1ß induced considerable phosphorylation of the NF-kB signaling pathway, which was inhibited by α-MG. Furthermore, the immunofluorescence staining demonstrated that α-MG could suppress IL-1ß-induced p65 nuclear translocation. In vivo, cartilage treated with α-MG showed attenuated degeneration and had low Osteoarthritis Research Society International (OARSI) scores compared with the control group. Taken together, these results show that α-MG has potential therapeutic value in the treatment of OA.

Hydrogen sulfide protects against endoplasmic reticulum stress and mitochondrial injury in nucleus pulposus cells and ameliorates intervertebral disc degeneration.

It has been suggested that excessive apoptosis in intervertebral disc cells induced by inflammatory cytokines, such as interleukin (IL)-1ß, is related to the process of intervertebral disc degeneration (IVDD). Hydrogen sulfide (H2S), a gaseous signaling molecule, has drawn attention for its anti-apoptosis role in various pathophysiological processes in degenerative diseases. To date, there has been no investigation of the correlation of H2S production and IVDD or of the effects of H2S on IL-1ß-induced apoptosis in nucleus pulposus (NP) cells. Here, we found that the expression levels of cystathionine ß-synthase (CBS) and cystathionine γ-lyase (CSE), two key enzymes in the generation of H2S, were significantly decreased in human degenerate NP tissues as well as in IL-1ß-treated NP cells. NaHS (H2S donor) administration showed a protective effect by inhibiting the endoplasmic reticulum (ER) stress response and mitochondrial dysfunction induced by IL-1ß stimulation in vitro, the effect was related to activation of the PI3K/Akt and ERK1/2 signaling pathways. Suppression of these pathways by specific inhibitors, LY294002 and PD98059, partially reduced the protective effect of NaHS. Moreover, in the percutaneous needle puncture disc degeneration rat tail model, disc degeneration was partially reversed by NaHS administration. Taken together, our results suggest that H2S plays a protective role in IVDD and the underlying mechanism involves PI3K/Akt and ERK1/2 signaling pathways-mediated suppression of ER stress and mitochondrial dysfunction in IL-1ß-induced NP cells.

Metformin protects against apoptosis and senescence in nucleus pulposus cells and ameliorates disc degeneration in vivo.

Intervertebral disc degeneration (IDD) is a complicated process that involves both cellular apoptosis and senescence. Metformin has been reported to stimulate autophagy, whereas autophagy is shown to protect against apoptosis and senescence. Therefore, we hypothesize that metformin may have therapeutic effect on IDD through autophagy stimulation. The effect of metformin on IDD was investigated both in vitro and in vivo. Our study showed that metformin attenuated cellular apoptosis and senescence induced by tert-butyl hydroperoxide in nucleus pulposus cells. Autophagy, as well as its upstream regulator AMPK, was activated by metformin in nucleus pulposus cells in a dose- and time-dependent manner. Inhibition of autophagy by 3-MA partially abolished the protective effect of metformin against nucleus pulposus cells' apoptosis and senescence, indicating that autophagy was involved in the protective effect of metformin on IDD. In addition, metformin was shown to promote the expression of anabolic genes such as Col2a1 and Acan expression while inhibiting the expression of catabolic genes such as Mmp3 and Adamts5 in nucleus pulposus cells. In vivo study illustrated that metformin treatment could ameliorate IDD in a puncture-induced rat model. Thus, our study showed that metformin could protect nucleus pulposus cells against apoptosis and senescence via autophagy stimulation and ameliorate disc degeneration in vivo, revealing its potential to be a therapeutic agent for IDD.

Resveratrol inhibits phosphorylation within the signal transduction and activator of transcription 3 signaling pathway by activating sirtuin 1 in SW1353 chondrosarcoma cells.

The present study assessed the mechanism by which resveratrol (Res) inhibits the growth of SW1353 chondrosarcoma cells and examined whether sirtuin 1 (Sirt1) activation affects phosphorylation within the signal transduction and activator of transcription 3 (STAT3) signaling pathway. The present study used SW1353 chondrosarcoma cells in the logarithmic phase of growth (control and treatment groups). The latter group was treated with Res at 25 and 50 µmol/l for 24 h, and cell viability, proliferation and apoptosis were analyzed using the cell counting kit­8 assay, colony counting and Hoechst staining, respectively. The expression levels of caspase­3, cleaved caspase­3, B­cell lymphoma­2 (BCL­2), BCL-2 associated X protein (Bax), STAT3 and phosphorylated (p­)STAT3) were measured by Western blotting. SW1353 cells were transfected with small interfering (si)RNA targeting Sirt1 and the expression levels of Sirt1, STAT3 and p-STAT3 were assessed. Exposure of SW1353 cells to Res reduced cell viability in a dose­dependent manner (P<0.01). Additionally, cell proliferation was significantly inhibited and the cell nuclei exhibited apoptotic characteristics. Cleaved caspase­3, Sirt1 and Bax levels were upregulated. The expression levels of BCL­2 and p­STAT3 were downregulated. Additionally, the BCL­2/Bax ratio was reduced compared with the control group. The total STAT3 level was unaffected. Res treatment activated Sirt1, however, in cells transfected with Sirt1­siRNA, the ability of resveratrol to suppress p­STAT3 expression was compromised. Overall, it was revealed that Res treatment induced apoptosis, inhibited proliferation and affected phosphorylation within the STAT3 signaling pathway by activating Sirt1 in SW1353 chondrosarcoma cells.

Efficacy and safety of mineralocorticoid receptor antagonists for patients with heart failure and diabetes mellitus: a systematic review and meta-analysis.

BACKGROUND: The aim of this study was to systematically assess the efficacy and safety of mineralocorticoid receptor antagonists (MRAs) for patients with heart failure (HF) and diabetes mellitus (DM). METHODS: We conducted a comprehensive search for controlled studies that evaluated the efficacy and safety of MRAs in patients with DM and HF. Medline, Embase and Cochrane databases were searched. Two reviewers independently identified citations, extracted data and evaluated quality. Risk estimations were abstracted and pooled where appropriate. RESULTS: Four observational studies were included. MRAs use was associated with reduced mortality compared with controls (RR = 0.78; 95% CI: 0.69-0.88; I(2) = 0%; P < 0.001). Increased risk of developing hyperkalaemia was observed in those patients taking MRAs (RR = 1.74; 95% CI: 1.27-2.38; I(2) = 0%; P = 0.0005). CONCLUSIONS: The current cumulative evidence suggests that MRAs can improve clinical outcomes but increase the risk of hyperkalaemia in patients with DM and HF. TRIAL REGISTRATION: PROSPERO CRD42015025690 .