PPAR γ activation in chondrocytes alleviates glucocorticoid-induced oxidative stress, mitochondrial impairment, and pyroptosis via autophagic flow enhancement

Osteoarthritis (OA) is a progressive age-related disease characterised by pathological changes in the synovium, articular cartilage, and subchondral bone, significantly reducing the patients' quality of life. This study investigated the role of glucocorticoids, specifically dexamethasone, in OA progression, with a particular focus on their effects on chondrocytes. Although glucocorticoids are commonly used for OA pain relief, our research demonstrated that high concentrations of dexamethasone may accelerate OA progression by enhancing the ability of reactive oxygen species to inhibit chondrocyte autophagy, resulting in cell death and accelerated cartilage degeneration. Despite reports on the acceleration of pathogenesis and cartilage damage in some patients of OA taking corticosteroids, the mechanism behind the same has not been investigated. This necessitates an investigation of the concentration-dependent changes in the cartilage cells upon dexamethasone administration. In addition, the protective effect of PPAR γ on chondrocytes can prevent the decrease in chondrocyte autophagy and delay cartilage degeneration. Therefore, our study suggests that the therapeutic use of glucocorticoids in OA treatment should be more nuanced considering their potential detrimental effects. Future investigations should focus on the mechanisms underlying the glucocorticoid-mediated modulation of cell death processes, which could provide insights into new therapeutic strategies for OA treatment.

Piceatannol suppresses inflammation and promotes apoptosis in rheumatoid arthritis‑fibroblast‑like synoviocytes by inhibiting the NF‑κB and MAPK signaling pathways

Rheumatoid arthritis (RA) is a chronic inflammatory disease that mainly targets the synovial membrane, thus causing stiffness, deformity and dysfunction of joints. To date, no effective anti-inflammatory treatments are available for RA. Piceatannol (PIC) is a natural derivative of resveratrol, which has been reported to attenuate the inflammatory response. To evaluate the effect of PIC on RA and to determine the underlying molecular target of PIC, both in vitro and in vivo experiments were performed in the present study. A CIA rat model was established to evaluate the therapeutic effects of PIC. TNF-α, IL-1β and IL-6 levels in blood were measured by ELISA. Western blotting, immunofluorescence analysis and reverse transcription-quantitative PCR (RT-qPCR) were used to analyze the expression levels of protein and mRNA. In vitro, RA-fibroblast-like synoviocytes (FLSs) were pretreated with PIC and subsequently stimulated with TNF-α. The results revealed that PIC significantly upregulated the expression levels of proapoptotic proteins such as Bax and cleaved caspase-3. PIC also significantly reduced the production of proinflammatory cytokines, including PGE2, IL-6 and IL-1β, and significantly downregulated the expression of cyclooxygenase-2 at both the mRNA and protein expression levels. Furthermore, PIC downregulated the expression of MMP-3 and MMP-13, which have been found to be highly expressed in the synovium of patients with RA. Mechanistically, PIC was capable of significantly downregulating the expression levels of proteins involved in the NF-κB and MAPK signaling pathways. The results of the in vivo experiments using a rat collagen-induced arthritis model demonstrated that PIC decreased the arthritis score and exerted beneficial effects in cartilage and significantly reduced the expression of MMP-13. In conclusion, the findings of the present study revealed that PIC could suppress the inflammatory response, promote apoptosis, and exert a significant regulatory effect on the NF-κB and MAPK signaling pathways in RA-FLSs. Therefore, PIC may represent a potential drug for the future treatment of RA.

Sparstolonin B suppresses free fatty acid palmitate-induced chondrocyte inflammation and mitigates post-traumatic arthritis in obese mice

Abnormal lipid metabolism, such as systemic increased free fatty acid, results in overproduction of pro‐inflammatory enzymes and cytokines, which is crucial in the development of obesity‐related osteoarthritis (OA). However, there are only a few drugs that target the lipotoxicity of OA. Recent researches have documented that the traditional Chinese medicine, Sparstolonin B (Ssn B), exerted anti‐inflammatory effects in various diseases, but not yet in OA. On the basis of this evidence, our works purposed to evaluate the effect of Ssn B on free fatty acid (FFA) palmitate (PA)‐stimulated human osteoarthritic chondrocytes and obesity‐associated mouse OA model. We found that Ssn B suppressed PA‐triggered inflammatory response and extracellular matrix catabolism in a concentration‐dependent approach. In vivo, Ssn B treatment inhibited cartilage degeneration and subchondral bone calcification caused by joint mechanical imbalance and alleviated metabolic inflammation in obesity. Mechanistically, co‐immunoprecipitine and molecular docking analysis showed that the formation of toll­like receptor 4 (TLR4)/myeloid differentiation protein‐2 (MD‐2) complex caused by PA was blocked by Ssn B. Subsequently, it leads to inactivation of PA‐caused myeloid differentiation factor 88 (MyD88)‐dependent nuclear factor‐kappaB (NF‐κB) cascade. Together, these findings demonstrated that Ssn B is a potential treatment agent for joint degenerative diseases in obese individuals.

The use of 2-octyl cyanoacrylate as an adjuvant to wound closure in total knee arthroplasty

PURPOSE

The efficacy of the use of 2-octyl cyanoacrylate (OCA) as an adjuvant to wound closure in preventing wound complications after total knee arthroplasty (TKA) is rarely reported. This study was aimed to determine whether the use of OCA as a supplement to conventional wound closure reduces the incidence of wound complications following TKA.

PATIENTS AND METHODS

This retrospective study reviewed 1106 consecutive patients who underwent TKA for symptomatic end-stage osteoarthritis (OA) between 2012 and 2017. The first 562 patients who did not receive OCA were grouped into the Control group, and the subsequent 544 patients who received OCA as an adjuvant to wound closure were grouped into the OCA group. All patients were followed up for at least 2 years. The main outcome was the development of operative site complications, including aseptic and infectious complications. Aseptic wound complications were wound leakage, hematoma, wound dehiscence and delayed wound healing, and infectious complication was mainly referred to the superficial infection.

RESULTS

No significant difference with regard to hematoma was observed between groups (3.0% vs. 3.7%, P = 0.617, φ = - 0.02). The incidences were significantly higher in the Control group versus the OCA group in regard to wound leakage (9.4% vs. 2.0%, P = 0.000, φ = 0.16), wound dehiscence (5.7% vs. 1.3%, P = 0.000, φ = 0.12), delayed wound healing (4.4% vs. 1.5%, P = 0.004, φ = 0.09) and superficial infection (2.0% vs. 0.4%, P = 0.022, φ = 0.07). No serious adverse events (AEs) occurred.

CONCLUSIONS

The present study showed that the addition of OCA reduced the incidence of wound leakage, wound dehiscence, delayed wound healing and superficial infection after TKA compared to conventional wound closure. Based on the outcomes above, we decide to use OCA routinely for wound closure after TKA.

LEVEL OF EVIDENCE

III, retrospective, cohort study.

Role of intra-wound powdered vancomycin in primary total knee arthroplasty

BACKGROUND

No study has evaluated the effect of topical powdered vancomycin in patients undergoing primary total knee arthroplasty (TKA). The goal of this study is to determine if this method reduces postoperative infection rates following primary TKA.

PATIENTS AND METHODS

This retrospective study reviewed 855 consecutive patients undergoing TKA. The first 418 patients, who did not receive topical vancomycin, were grouped into the control group and the subsequent 437 patients, who received powdered vancomycin applied to the target joint prior to wound closure, were grouped into the treatment group.

RESULTS

The control group was found to have 18 infectious complications (4.3%) compared with 6 (1.4%) in the treatment group, which differed significantly (p<0.05). When comparing the rates of infectious complications independently, there was no significant difference in the rate of superficial infection (3.1% vs. 1.4%; p>0.05), while the difference in prevalence of periprosthetic joint infection (PJI) was statistically significant (1.2% vs. 0; p<0.05). No serious adverse events (AEs) occurred.

DISCUSSION

Topical application of powdered vancomycin may present a reasonable means of decreasing the risk of infectious complications following TKA. There were no serious AEs associated with topical vancomycin. Further research is needed to focus on its long-term efficacy and safety.

LEVEL OF EVIDENCE

III, retrospective, cohort study.

Pharmacological blockade of PCAF ameliorates osteoarthritis development via dual inhibition of TNF-α-driven inflammation and ER stress

Background

Epigenetic mechanisms have been reported to play key roles in osteoarthritis (OA) development. P300/CBP-associated factor (PCAF) is a member of the histone acetyltransferases, which exhibits a strong relationship with endoplasmic reticulum (ER) stress and transcription factor nuclear factor kappa B (NF-κB) signals. Salidroside, a natural histone acetylation inhibitor, showed its anti-inflammatory and anti-apoptotic effects in lipopolysaccharide (LPS)-stimulated microglia cells in our previous study. However, whether Sal has a protective effect against OA remains unknown, and its relationships to PCAF, NF-κB, and the ER stress pathway should be explored further.

Methods

We identified the role of PCAF in the pathogenesis of OA and determined the chondroprotective effect of Sal on both tumor necrosis factor alpha (TNF-α)-treated human chondrocytes and a destabilized medial meniscus (DMM) mouse OA model.

Findings

We found increased PCAF expression in human OA cartilage and TNF-α-driven chondrocytes. Meanwhile, silencing of PCAF attenuated nuclear p65 and C/EBP homologous protein levels in chondrocytes upon TNF-α stimulation. Furthermore, Sal was found to specifically bind to the inhibitory site of the PCAF protein structure, which subsequently reversed the TNF-α-induced activation of NF-κB signal and ER stress-related apoptosis in chondrocytes. In addition, the protective effect of Sal and its inhibitory effects on PCAF as well as inflammatory- and ER stress-related markers were also observed in the mouse DMM model.

Interpretation

Pharmacological blockade of PCAF by Sal ameliorates OA development via inhibition of inflammation and ER stress, which makes Sal a promising therapeutic agents for the treatment of OA.

Peiminine inhibits the IL-1β induced inflammatory response in mouse articular chondrocytes and ameliorates murine osteoarthritis

Osteoarthritis (OA) is a common arthrosis characterized by degeneration and inflammation of articular cartilage. In recent decades, peiminine (Pm) has been identified as one of the active ingredients of Fritillaria plants. According to reports, Pm has a potent anti-inflammatory effect in various diseases. However, the effectiveness of Pm as an anti-inflammatory in OA has not previously been reported. This research aims to evaluate the anti-inflammatory effect of Pm on interleukin (IL)-1β-induced mice chondrocytes and its chondroprotective effect in a mouse OA model with surgical destabilization of the medial meniscus. IL-1β-induced expression of nitric oxide (NO), prostaglandin E2 (PGE2), cyclooxygenase-2 (COX-2), tumor necrosis factor alpha (TNF-α), inducible nitric oxide synthase (iNOS) and interleukin-6 (IL-6) were all inhibited significantly by Pm pretreatment in vitro. In addition, Pm also inhibited the expression of thrombospondin motifs 5 (ADAMTS-5) and matrix metalloproteinase-13 (MMP-13), which are responsible for the degradation of the extracellular matrix (ECM). Additionally, the degradation of aggrecan and collagen II was reversed by Pm. Furthermore, Pm inhibited Akt phosphorylation and the nuclear transfer of nuclear factor-κB (NF-κB) and activated Nrf2/HO-1 signaling pathways both in vitro and in vivo. These findings suggested that Pm alleviated inflammatory effects in the IL-1β-induced chondrocytes. Therefore, Pm might be a potential therapeutic agent for OA.

A new technique for medial-end comminuted clavicle fractures

Fractures of the medial comminuted clavicle are rare injuries but are associated with significant morbidity and mortality. Although rare, such injuries deserve rapid diagnosis and effective treatment to avoid future complications. An optimal, standardized operative treatment has not yet been established. We presented a medial-end comminuted clavicle fracture and demonstrated successful results using a bridging plate technique across the sternum maintaining reduction and achieving union. We aim to provide an alternative technique to fix a displaced periarticular medial clavicle fracture, which we believe is simple, safer and promising.

Hypoxia preconditioning promotes bone marrow mesenchymal stem cells survival by inducing HIF-1α in injured neuronal cells derived exosomes culture system

Bone marrow derived stem cells (BMSCs) transplantation are viewed as a promising therapeutic candidate for spinal cord injury (SCI). However, the inflammatory microenvironment in the spinal cord following SCI limits the survival and efficacy of transplanted BMSCs. In this study, we investigate whether injured neuronal cells derived exosomes would influence the survival of transplanted BMSCs after SCI. In order to mimic the microenvironment in SCI that the neuronal cells or transplanted BMSCs suffer in vivo, PC12 cells conditioned medium and PC12 cell’s exosomes collected from H₂O₂-treated PC12 cell’s culture medium were cultured with BMSCs under oxidative stress in vitro. PC12 cells conditioned medium and PC12 cell’s exosomes significantly accelerated the apoptosis of BMSCs induced by H₂O₂. Moreover, the cleaved caspase-3, cytochrome (Cyt) C, lactate dehydrogenase (LDH) releases, and apoptotic percentage were increased, and the ratio of Bcl-2/Bax and cell viability were decreased. Inhibition of exosome secretion via Rab27a small interfering RNA prevented BMSCs apoptosis in vitro. In addition, hypoxia-preconditioned promoted the survival of BMSCs under oxidative stress both in vivo after SCI and in vitro. Our results also indicate that HIF-1α plays a central role in the survival of BMSCs in hypoxia pretreatment under oxidative stress conditions. siRNA-HIF-1α increased apoptosis of BMSCs; in contrast, HIF-1α inducer FG-4592 attenuated apoptosis of BMSCs. Taken together, we found that the injured PC12 cells derived exosomes accelerate BMSCs apoptosis after SCI and in vitro, hypoxia pretreatment or activating expression of HIF-1α to be important in the survival of BMSCs after transplantation, which provides a foundation for application of BMSCs in therapeutic potential for SCI.

Effect of autophagy induced by dexamethasone on senescence in chondrocytes

The aim of the current study was to explore the effects of dexamethasone (DXM) on autophagy and senescence in chondrocytes. Collagen II and aggrecan were examined in normal chondrocytes isolated from Sprague‑Dawley rats. Following stimulation with DXM, LysoTracker Red staining, monodansylcadaverine (MDC) staining, green fluorescent protein‑red fluorescent protein‑light chain 3 (LC3) and western blotting were used to detect autophagy levels in the chondrocytes. Mechanistic target of rapamycin (mTOR) pathway‑associated molecules were investigated by western blotting. Cell senescence was analyzed by senescence‑associated (SA)‑β‑galactosidase (β‑gal) staining. A dose‑dependent increase in the number of autophagic vacuoles was observed in the DXM‑treated chondrocytes, as demonstrated by LysoTracker Red and MDC staining. A dose‑dependent increase in autophagosome formation was observed in the DXM‑treated chondrocytes. Expression of LC3‑II and beclin‑1 was increased by DXM, in particular in the cells treated with DXM for 4 days. However, P62 expression was reduced as a result of treatment. SA‑β‑gal staining indicated that DXM increased cell senescence. Notably, DXM‑induced cell senescence was exacerbated by the autophagic inhibitor 3‑MA. Autophagy induced by DXM protected chondrocytes from senescence, and it is suggested that the mTOR pathway may be involved in the activation of DXM‑induced autophagy.

An intraoperative device to restore femoral offset in total hip arthroplasty

Background

Leg length discrepancy (LLD) after total hip arthroplasty (THA) can lead to unsatisfactory outcome. Our objective was to design and evaluate a simple and reliable intraoperative device (Length-offset Lever) to minimize leg length discrepancy.

Methods

This device was used in 51 patients undergoing primary total hip replacements. The leg length discrepancy was measured pre- and postoperatively based on plain radiographs.

Results

Preoperative radiographic leg length discrepancy averaged 13.5 ± 6.2 mm. Leg length discrepancy showed significant improvement, with a postoperative average of 4.1 ± 2.3 mm (p < 0.0001). There were no complications associated with this device.

Conclusions

The ‘Length-offset Lever’ is a useful intraoperative tool to restore anatomic femoral offset and height of femoral head.

Apoptosis, senescence, and autophagy in rat nucleus pulposus cells: Implications for diabetic intervertebral disc degeneration

This research was aimed to study the mechanisms by which diabetes aggravates intervertebral disc degeneration (IDD) and to discuss the relationship between autophagy and IDD in nucleus pulposus (NP) cells. Sixteen weeks after injecting streptozotocin (STZ), the intervertebral discs (IVDs) were studied by histology, Alcian blue, 1,9-dimethylmethylene blue (DMMB), immunohistochemistry, and RT-PCR to explore the IDD. The apoptosis and senescence of NP cells was investigated by terminal deoxyribonucleotidyl transferase (TDT)-mediated dUTP-digoxigenin nick end labeling (TUNEL) assay, immunohistochemistry, and Western blot for caspase3, caspase8, caspase9, and p16lnk4A (increased in cellular senescence). The level of autophagy in NP cells was detected by Western blot, immunohistochemistry, and transmission electron microscopy (TEM). The proteoglycan and collagen II in the extracellular matrix and the aggrecan and collagen II mRNA expression in NP cells of diabetic rats were decreased compared with the control group. Diabetes increased apoptosis of NP cells and led to activations of initiators of intrinsic (caspases-9) and extrinsic (caspase-8) pathways as well as their common executioner (caspase-3). Cellular senescence was increased about twofold in NP of diabetic rats. In addition, the Western blot, immunohistochemistry, and TEM demonstrated higher level of autophagy in NP cells of diabetic rats than control rats to a statistically significant extent. These findings support that diabetes induced by STZ can cause IDD by accelerating the apoptosis and senescence of NP cells excluding the overweight influence. And the results suggest that the autophagy may be a response mechanism to the change of NP cells in diabetic rats.

Nicotine-induced chondrogenic differentiation of human bone marrow stromal cells in vitro

PURPOSE

Nicotine has been reported that it has a dose-dependent effect on matrix mineralization by human bone marrow cells. However, there is no relevant research concerning on chondrogenic differentiation potential of bone marrow stromal stem cells (BMSCs) treated with nicotine in vitro. The aims of the study were to examine the effects of nicotine (0, 10(-7), 10(-6) and 10(-5) M) on the proliferation and chondrogenic differentiation of BMSCs from three healthy donors in vitro.

METHODS

BMSCs proliferation was analyzed by CCK8 assay and real-time polymerase chain reaction was used to assay the expression of type II collagen, aggrecan, type I collagen and type X collagen. The proteoglycan content was stained by Alcian blue, and the sulfated glycosaminoglycan (sGAG) content of BMSCs was quantified spectrofluorometrically using dimethylmethylene blue.

RESULTS

The cell viability was not significantly impaired until up to a concentration of 10(-5) M nicotine. Nicotine promoted the proliferation and enhanced the expression of type II collagen at the level up to 10(-6) M (P < 0.05). The expression of aggrecan was reduced at the concentration of 10(-5) M nicotine at day 14 (P < 0.05), and there was no significant difference in aggrecan gene expression at 10(-7) and 10(-6) M nicotine levels compared to control group (n.s.). Also the fibroblastic and hypertrophic gene expressions were down-regulated in the chondrogenic medium with 10(-7)-10(-5) M nicotine (P < 0.05).

CONCLUSION

It was implied that local application of nicotine at an appropriate concentration may be a promising approach for enhancing chondrogenic differentiation capacity of BMSCs in cell-based cartilage tissue engineering. Also these results indicate that nicotine maybe a potentially useful drug for the treatment of Osteoarthritis.

[Biocompatibility of alpha-calcium sulfate hemihydrate (CSH)/multi-walled carbon nanotube (MWCNT) composites for bone reconstruction application]

We examined the biocompatibility and the safety of a-calcium sulfate hemihydrate (CSH)/multi-walled carbon nanotube (MWCNT) composites for bone reconstruction application. The biocompatibility of the CSH/MWCNT composites was evaluated by the measures which taking L929 fibroblast cells cultured in the extracted liquid of the composite soaking solution and putting bone marrow stromal cells planted on the composite pellets in vitro, respectively. The cell proliferation was evaluated by MTT test and further observed using an inverted optical microscope and a scanning electric microscope. The toxicity of the composites was evaluated by acute and subacute systemic toxicity test. Long-term muscle and bone implantation in vivo tests were also conducted. L929 fibroblast cells grew well in the extracted liquid, as well as bone marrow stromal cells that could adhere on the surface of sample pellets and proliferated rapidly. MTT test showed that there were no significant differences between the experimental and control groups (P > 0.05). In vivo test manifested that the composites were no toxicity, no irritation to skin and good for bone defect reconstruction. It was proved that a-calcium sulfate hemihydrate (CSH)/multi-walled carbon nanotube (MWCNT) composites exhibited excellent biocompatibility for the potential application in bone tissue engineering.

[Intraoperative ultrasonographic detection of liver metastasis from tumors of the digestive tract]

OBJECTIVE

To ascertain the value of intraoperative ultrasonography to early detect liver metastasis from tumors of the digestive tract.

METHODS

Intraoperative ultrasonography (US) of the liver was performed in 176 patients with confirmed diagnosis of cancer of the stomach and colon. All the nodules detected were either resected or needle biopsied for histological diagnosis. The results of the liver US were compared with those of pre-operative trans-abdominal US, CT scanning and intraoperative exploration.

RESULTS

Liver metastasis was detected by intraoperative US in 43 of the 176 patients (24.4%), with a total of 81 nodules found. Liver metastasis was confirmed histologically in 42 of the 43 cases (97.7%), the frequency of which was significantly higher than that of preoperative transabdominal US, CT scan and surgical exploration (P < 0.05, P < 0.01). It was particularly superior for the detection of liver metastasis less than 2 cm in diameter.

CONCLUSION

Intraoperative ultrasonography is sensitive enough to early detect tumors of the stomach and colon metastasized to the liver.