Haixiao Liu

Pterostilbene inhibits inflammation and ROS production in chondrocytes by activating Nrf2 pathway

Pterostilbene has been reported as a potential drug to inhibit oxidative stress and inflammation. However, the effect of pterostilbene on chondrocytes and osteoarthritis remains to be elucidated. We sought to investigate whether pterostilbene could protect chondrocytes from inflammation and ROS production through factor erythroid 2-related factor 2 (Nrf2) activation. The pterostilbene toxicity on chondrocytes collected from cartilages of Sprague-Dawley rats was assessed by CCK-8 test. Immunofluorescence and Western blotting explored the nuclear translocation of Nrf2. Nrf2 expression was silenced by siRNA to evaluate the involvement of Nrf2 in the effect of pterostilbene on chondrocytes. Finally, osteoarthritis model was established by the transection of anterior cruciate ligament and partial medial meniscectomy in rats, and then these rats received pterostilbene 30 mg/kg, daily, p.o. for 8 weeks. Histology and immunohistochemistry were used to assess histopathological change and Nrf2 expression in cartilage. Nuclear translocation of Nrf2 was stimulated by pterostilbene without cellular toxicity. Pterostilbene inhibited the level of COX-2, iNOS, PGE2, and NO, as well as the mitochondrial and total intracellular ROS production induced by IL-1β in chondrocytes, partially reversed by the Nrf2 silencing. Pterostilbene prevented cartilage degeneration and promoted the nuclear translocation of Nrf2 in cartilage. These results suggest that pterostilbene could inhibit the IL-1β-induced inflammation and ROS production in chondrocytes by stimulating the nuclear translocation of Nrf2.

Trehalose ameliorates oxidative stress-mediated mitochondrial dysfunction and ER stress via selective autophagy stimulation and autophagic flux restoration in osteoarthritis development.

Oxidative stress-related apoptosis and autophagy play crucial roles in the development of osteoarthritis (OA), a progressive cartilage degenerative disease with multifactorial etiologies. Here, we determined autophagic flux changes and apoptosis in human OA and tert-Butyl hydroperoxide (TBHP)-treated chondrocytes. In addition, we explored the potential protective effects of trehalose, a novel Mammalian Target of Rapamycin (mTOR)-independent autophagic inducer, in TBHP-treated mouse chondrocytes and a destabilized medial meniscus (DMM) mouse OA model. We found aberrant p62 accumulation and increased apoptosis in human OA cartilage and chondrocytes. Consistently, p62 and cleaved caspase-3 levels increased in mouse chondrocytes under oxidative stress. Furthermore, trehalose restored oxidative stress-induced autophagic flux disruption and targeted autophagy selectively by activating BCL2 interacting protein 3 (BNIP3) and Phosphoglycerate mutase family member 5 (PGAM5). Trehalose could ameliorate oxidative stress-mediated mitochondrial membrane potential collapse, ATP level decrease, dynamin-related protein 1 (drp-1) translocation into the mitochondria, and the upregulation of proteins involved in mitochondria and endoplasmic reticulum (ER) stress-related apoptosis pathway. In addition, trehalose suppressed the cleavage of caspase 3 and poly(ADP-ribose) polymerase (PARP) and prevented DNA damage under oxidative stress. However, the anti-apoptotic effects of trehalose in TBHP-treated chondrocytes were partially abolished by autophagic flux inhibitor chloroquine and BNIP3- siRNA. The protective effect of trehalose was also found in mouse OA model. Taken together, these results indicate that trehalose has anti-apoptotic effects through the suppression of oxidative stress-induced mitochondrial injury and ER stress which is dependent on the promotion of autophagic flux and the induction of selective autophagy. Thus, trehalose is a promising therapeutic agent for OA.

Wogonoside inhibits IL-1β induced catabolism and hypertrophy in mouse chondrocyte and ameliorates murine osteoarthritis

The inflammatory environment is correlated with extracellular matrix (ECM) degradation and chondrocyte hypertrophy in the development of osteoarthritis (OA). Previous studies have reported the anti-inflammatory effects of wogonoside in several diseases. In the present study, we investigated the protective effects of wogonoside in relation to the development of OA and delineated the potential mechanism. In vitro, wogonoside decreased the production of pro-inflammatory cytokines like Nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor alpha (TNF-α), and interleukin-6 (IL-6). It also inhibited the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) both at gene and protein levels. Wogonoside also inhibited hypertrophy and the generation of vascular endothelial growth factor (VEGF) in interleukin-1β (IL-1β)-induced chondrocytes. Moreover, wogonoside promoted the expression of anabolic factors Sox-9, type two collagen and aggrecan while inhibiting the expression of catabolic factors such as matrix metalloproteinases (MMPs) and thrombospondin motifs 5 (ADAMTS-5) in mouse chondrocytes. Mechanistically, we found that wogonoside inhibited nuclear factor kappa B/ hypoxia-inducible factor two alpha (NF-κB/HIF-2α) activation via the phosphatidylinositol 3 kinase (PI3K) /AKT pathway. The protective effects of wogonoside were also observed in vivo and the pharmacokinetic results of wogonoside indicated that good systemic exposure was achievable after oral administration of wogonoside. In conclusion, our stduy demonstrates that wogonoside attenuates IL-1β-induced ECM degradation and hypertrophy in mouse chondrocytes via suppressing the activation of NF-κB/HIF-2α by the PI3K/AKT pathway. Moreover, wogonoside ameliorates OA progression in vivo, indicating that wogonoside may serve as a promising therapeutic agent for the treatment of OA.The inflammatory environment is correlated with extracellular matrix (ECM) degradation and chondrocyte hypertrophy in the development of osteoarthritis (OA). Previous studies have reported the anti-inflammatory effects of wogonoside in several diseases. In the present study, we investigated the protective effects of wogonoside in relation to the development of OA and delineated the potential mechanism. In vitro, wogonoside decreased the production of pro-inflammatory cytokines like Nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor alpha (TNF-α), and interleukin-6 (IL-6). It also inhibited the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) both at gene and protein levels. Wogonoside also inhibited hypertrophy and the generation of vascular endothelial growth factor (VEGF) in interleukin-1β (IL-1β)-induced chondrocytes. Moreover, wogonoside promoted the expression of anabolic factors Sox-9, type two collagen and aggrecan while inhibiting the expression of catabolic factors such as matrix metalloproteinases (MMPs) and thrombospondin motifs 5 (ADAMTS-5) in mouse chondrocytes. Mechanistically, we found that wogonoside inhibited nuclear factor kappa B/ hypoxia-inducible factor two alpha (NF-κB/HIF-2α) activation via the phosphatidylinositol 3 kinase (PI3K) /AKT pathway. The protective effects of wogonoside were also observed in vivo and the pharmacokinetic results of wogonoside indicated that good systemic exposure was achievable after oral administration of wogonoside. In conclusion, our stduy demonstrates that wogonoside attenuates IL-1β-induced ECM degradation and hypertrophy in mouse chondrocytes via suppressing the activation of NF-κB/HIF-2α by the PI3K/AKT pathway. Moreover, wogonoside ameliorates OA progression in vivo, indicating that wogonoside may serve as a promising therapeutic agent for the treatment of OA.

Percutaneous quadriceps tendon pie-crusting release of extension contracture of the knee.

To release extension contracture of the knee, the authors used a minimally invasive technique: percutaneous quadriceps tendon pie-crusting release. Percutaneous pie-crusting release was performed using an 18-gauge needle to puncture the stiff fibrous band of the distal and lateral quadriceps tendon under maximum knee flexion. Quadriceps contracture was gradually released by multiple needle punctures. A knee brace was prescribed for one week and knee flexion exercises were performed on the first postoperative day. This technique was performed in seven post-traumatic stiff knees and five stiff total knee arthroplasties. Mean maximum flexion increased from 37° preoperatively to 50° after arthrolysis and 107(o) after pie-crusting. At a mean follow-up of eight months, mean maximum flexion was 103°. There were no major complications. The technique of quadriceps tendon pie-crusting release is a simple, minimally invasive and effective treatment for knee extension contracture.

A mini-invasive technique for severe arthrofibrosis of the knee: A technical note.

PURPOSE In this article, a mini-invasive technique is described, which consists of arthroscopic adhesiolysis and quadriceps pie-crusting lengthening basing on pre-operative sonographic examination. Sonographic diagnostic value of quadriceps tendon fibrosis is also evaluated. METHODS Pre-operative sonographic examination was performed to make an accurate location diagnosis of quadriceps fibrosis. After arthroscopic adhesiolysis, percutaneous pie-crusting release was performed basing on preoperative sonographic examination. An 18-gauge needle was used to puncture the stiff fibrous band of the distal and lateral quadriceps tendon under maximum knee flexion. The contractural quadriceps tendon is gradually released after 60-100 needle punctures. RESULTS This technique was performed in five post-traumatic stiff knees and three stiff knees after previous infection. The contractural rectus femoris tendon is average 22% thinner than contralateral parts according to sonographic measurement. Mean maximum flexion increased from 35° preoperatively to 80° after arthroscopic adhesiolysis and 120° after pie-crusting. CONCLUSIONS This technique is a simple, effective and mini-invasive method, allowing an immediate, aggressive rehabilitation postoperatively. Pre-operative sonographic location of quadriceps tendon fibrosis could potentially improve the efficacy and accuracy of percutaneous pie-crusting procedures.

Association of osteoarthritis and circulating adiponectin levels: a systematic review and meta-analysis

BackgroundThe objective of this study was to perform a meta-analysis to investigate the specific relationship between the expression level of circulating adiponectin and osteoarthritis (OA).MethodMultiple databases were searched to estimate the high quality of studies relevant to adiponectin and OA. We extracted the data from the eligible studies and included them in the meta-analysis using a random effects model. Subgroup analysis and meta-regression were further performed to explore the potential sources of heterogeneity.ResultsTen articles consisting of thirteen case-control studies that contained a combined total of 1255 subjects. Our results revealed that the OA patients displayed higher adiponectin levels than the healthy controls (SMD = 0.327, 95% CI: 0.11–0.55, P = 0.003). The ethnicity-stratified subgroup analysis indicated that the adiponectin was a sensitive biomarker in both Caucasians (P = 0.021) and Asians (P = 0.037). Moreover, the meta-regression analysis suggested that the sample size (P = 0.03) and nationality (p = 0.01) could account for a part of heterogeneity in our study.ConclusionTaken together, the current study indicated that the adiponectin expression levels were higher in the OA patients than in the healthy controls and might be associated with OA prevalence.

No effectiveness of anticoagulants for thromboprophylaxis after non-major knee arthroscopy: a systemic review and meta-analysis of randomized controlled trials

Arthroscopic knee surgery is the most commonly performed orthopedic procedure worldwide and whether thromboprophylaxis should be undertaken after knee arthroscopy is still controversial. To evaluate the efficacy of thromboprophylaxis for deep venous thrombosis (DVT) and venous thromboembolism (VTE) after knee arthroscopic surgery. A meta-analysis was conducted using data from eight randomized trials (4148 patients) to compare thromboprophylaxis with placebo or no prophylactic treatment in patients undergoing knee arthroscopy. The benefits and harms of thromboprophylaxis were evaluated, including the incidence of asymptomatic DVT, symptomatic VTE, pulmonary embolism and anti-coagulation related adverse events. Thromboprophylaxis significantly decreased the incidence of DVT (95% CI 0.07–0.64, P = 0.006) and symptomatic VTE in patients undergoing knee arthroscopy (95% CI 0.23–0.76, P = 0.004), but not significantly decreased the incidence of pulmonary embolism (n.s.). Regarding to non-major knee arthroscopy surgery (simple surgical procedures without ligament reconstruction), no significant difference of the incidence of DVT or symptomatic VTE was noted between thromboprophylactic group and control group (n.s.). Thromboprophylactic treatment showed higher incidence rate of anti-coagulation related adverse events compared with the control group (95% CI 1.12–1.90, P = 0.005). There was no significant difference of the incidence of clinically relevant major bleeding between the two groups (n.s.). This meta-analysis indicates no effectiveness of thromboprophylaxis for preventing DVT or symptomatic VTE in patients undergoing non-major knee arthroscopy. Regarding to patient undergoing knee ligament construction, the thromboprophylactic strategy should mainly take into account the patient’s risk factors.

Inhibition of Dll4/Notch1 pathway promotes angiogenesis of Masquelet’s induced membrane in rats

The Masquelet’s induced membrane technique for repairing bone defects has been demonstrated to be a promising treatment strategy. Previous studies have shown that the vessel density of induced membrane is decreased in the late stage of membrane formation, which consequently disrupts the bone healing process. However, relatively little is known about certain mechanisms of vessel degeneration in the induced membrane tissue and whether promotion of angiogenesis in induced membranes can improve bone regeneration. Here, we showed that the Delta-like ligand 4/ Notch homolog 1 (Dll4/Notch1) pathway was relatively activated in the late stage of induced membrane, especially at the subcutaneous site. Then, DAPT, a classical γ-secretase inhibitor, was applied to specifically inhibit Notch1 activation, followed by up-regulation of vascular endothelial growth factor receptor 2 (VEGFR2) and CD31 expression. DAPT-modified induced membranes were further confirmed to contribute to bone regeneration after autogenous bone grafting. Finally, in vitro experiments revealed that knocking down Notch1 contributed to the functional improvement of endothelial progenitor cells (EPCs) and that DAPT-treated induced membrane tissue was more favorable for angiogenesis of EPCs compared with the vehicle group. In conclusion, the present findings demonstrate that Dll4/Notch1 signaling is negatively associated with the vessel density of induced membrane. Pharmacological inhibition of Notch1 attenuated the vessel degeneration of induced membrane both in vitro and in vivo, which consequently improved bone formation at the bone defect site and graft resorption at the subcutaneous site.Bone grafts: improving chances of graft acceptanceRepairs to serious bone injuries may be improved by blocking a signaling pathway that causes newly forming membranes to fail. Masquelet’s technique involves placing acrylic spacers in areas of bone damage, inducing the formation of vascularised membranes which encourage the body to accept bone grafts. However, sometimes Masquelet’s membranes do not form correctly, leading to weaknesses in bone repairs and potential graft rejection. In experiments on rats, Qian Tang from Wenzhou Medical University, China, and coworkers found that a particular signaling pathway, D114/Notch1, was upregulated around 6 weeks post-operation, reducing blood vessel density and limiting new vessel growth, weakening the membranes. The team inhibited this pathway using an existing therapy that prevents blood clots. This treatment improved bone repairs by promoting the formation and function of blood vessels in membranes.

Extramedullary versus intramedullary femoral alignment technique in total knee arthroplasty: a meta-analysis of randomized controlled trials

BackgroundThere is no consensus whether the use of the extramedullary femoral cutting guide takes advantage over the intramedullary one in total knee arthroplasty. The aim of this study was to compare the extramedullary femoral alignment guide system with the conventional intramedullary alignment guide system for lower limb alignment, blood loss, and operative time during total knee arthroplasty.MethodsThe Medline, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), Wan Fang Chinese Periodical, Google, and reference lists of all the included studies were searched for randomized controlled trials. The following parameters were compared between the extramedullary technique and the intramedullary technique: (1) lower limb coronal alignment, (2) coronal alignment of femoral component, (3) sagittal alignment of femoral component, (4) blood loss, (5) and operation time.ResultsFour randomized controlled trials consisting of 358 knees were included in our study. There was no significant difference between the extramedullary and intramedullary groups for the lower limb coronal alignment (RR = 1.20, 95%CI 0.28~5.21, n.s.), coronal alignment of femoral component (RR = 0.65, 95%CI 0.19~2.22, n.s.), and sagittal alignment of femoral component (RR = 0.73, 95%CI 0.38~1.41, n.s.). A reduced blood loss was associated with the use of the extramedullary guide (MD = −120.34, 95%CI −210.08~−30.59, P = 0.009). No significant difference in operation time was noted between the two groups (MD = 1.41, 95%CI −1.82~4.64, n.s.).ConclusionsNeither extramedullary nor intramedullary femoral alignment is more accurate than the other in facilitating the femoral cut in total knee arthroplasty. Use of the extramedullary guide results in less blood loss and exhibits a similar operation time as compared with the intramedullary guide.

An ultrastructural study of chondroptosis: programmed cell death in degenerative intervertebral discs in vivo

Apoptosis has been regarded to mediate intervertebral disc degeneration (IDD); however, the basic question of how the apoptotic bodies are cleared in the avascular intervertebral disc without phagocytes, which are essential to apoptosis, remains to be elucidated. Our goals were to investigate the ultrastructure of nucleus pulposus (NP) cells undergoing chondroptosis, a variant of apoptotic cell death, in a rabbit annular needle‐puncture model of IDD. Experimental IDD was induced by puncturing discs with a 16‐G needle in New Zealand rabbits. At 4 and 12 weeks after puncture, progressive degeneration was demonstrated by X‐ray, magnetic resonance imaging and histological staining. TUNEL staining suggested a significant increase in the apoptosis index in the degenerated NP. However, the percentage of apoptotic cells with the classic ultrastructure morphology was much less than that with chondroptotic ultrastructure morphology under transmission electron microscopy (TEM). The chondroptotic cells from the early to late stage were visualized under TEM. In addition, the percentage of chondroptotic cells was significantly enhanced in the degenerated NP. Furthermore, ‘paralyzed’ cells were found in the herniated tissue. Western blotting revealed an increase in caspase3 expression in the degenerated NP. The expression of the Golgi protein (58K) was increased by the fourth week after puncture but decreased later. These findings indicate that chondroptosis is a major type of programmed cell death in the degenerated rabbit NP that may be related to the progressive development of IDD.