Inhibition of Rac1 activity by NSC23766 prevents cartilage endplate degeneration via Wnt/ß-catenin pathway.

Cartilage endplate (CEP) degeneration has been considered as one of important factors related to intervertebral disc degeneration (IVDD). Previous researches have showed that Rac1 played a pivotal role in chondrocyte differentiation. However, the effect of Rac1 during the process of CEP degeneration remains unclear. Herein, we explored the effect of Rac1 on CEP degeneration and elucidated the underlying molecular mechanism. We found expression of Rac1-GTP increased in human-degenerated CEP tissue and IL-1ß-stimulated rat endplate chondrocytes (EPCs). Our study revealed that Rac1 inhibitor NSC23766 treatment promoted the expression of collagen II, aggrecan and Sox-9, and decreased the expression of ADTAMTS5 and MMP13 in IL-1ß-stimulated rat EPCs. Moreover, we also found that NSC23766 could suppress the activation of Wnt/ß-catenin pathway, suggesting that the beneficial effects of Rac1 inhibition in EPCs are mediated through the Wnt/ß-catenin signalling. Besides, puncture-induced rats models showed that NSC23766 played a protective role on CEP and disc degeneration. Collectively, these findings demonstrated that Rac1 inhibition delayed the EPCs degeneration and its potential mechanism may be associated with Wnt/ß-catenin pathway regulation, which may help us better understand the association between Rac1 and CEP degeneration and provide a promising strategy for delaying the progression of IVDD.

The projection of the thoracic nerve roots and their connection with intervertebral discs: a cadaver and radiological study.

BACKGROUND: The anatomical features of the thoracic nerve roots in connection with intervertebral discs may prevent surgery-related complications and improve patients' neurological functional status during thoracic spine surgery. There is limited literature evidence regarding this concept using cadavers. PURPOSE: To elucidate the qualitative anatomical features of the thoracic nerve roots in connection with intervertebral discs. MATERIAL AND METHODS: Fifteen formalin-preserved spine specimens were used in this study. Small pieces of stainless-steel wires were placed along the root sleeves from their points of origin, after exposing the dural sac and bilateral nerve roots. The standard anteroposterior and lateral radiographs were taken after the placement of the wires. Measurements were done on radiographs using the picture archiving communication system. RESULTS: Take-off angles of the nerve roots at the coronal plane gradually increased from the level of T2 (36.1°±2.72°) to T9 (84.1°±1.84°) and from T9, it decreased to T12 (46.3° ± 2.67°). Similar variation tendency was discovered in take-off angles of the nerve roots at the sagittal plane. No consistent tendency was found both in the distance from the origin of the root sleeve to its superior and inferior vertebral endplate. Distance from the origin of the root sleeve to the posterior midline (DM) exponentially decreased from T1 (8.2 ± 0.87 mm) to T4 (6.0 ± 0.93 mm). It slowly increased from T5 (5.5 ± 0.68 mm) to T12 (10.9 ± 1.79 mm), with T5 having the smallest DM. Distance between the origins of neighboring nerve roots showed an obvious increase from the T1-T2 interval (23.1 ± 2.22 mm) to T7-T8 interval (30.9 ± 2.68 mm). However, it progressively decreased at the T10-T11 interval (26.0 ± 2.40 mm). CONCLUSION: The dimensions of the thoracic nerve roots vary greatly from T1 to T12 intervertebral discs. Sound knowledge of these anatomical features of the thoracic nerve is mandatory for the thoracic spine surgery, especially in the posterolateral approach and transforaminal endoscopic surgery.

Inhibition of EZH2 ameliorates cartilage endplate degeneration and attenuates the progression of intervertebral disc degeneration via demethylation of Sox-9.

BACKGROUND: Cartilaginous endplate (CEP) degeneration is considered as one of the major causes of intervertebral disc degeneration (IVDD) which causes low back pain. Recent studies have proved that epigenetic alteration is involved in a variety of diseases. This work explored the role of histone methyltransferase enhancer of zeste homologue 2 (EZH2) in CEP degeneration, as well as its underlying epigenetic mechanisms, and confirmed the effect of EZH2 knockdown on delaying IVDD development. METHODS: Western blotting, immunofluorescence staining, and ChIP assay were applied to demonstrate the molecular mechanism of EZH2 in CEP tissue. The therapeutic potential of EZH2 was investigated using puncture-induced rat models. FINDINGS: The EZH2 expression was upregulated in human and rat CEP tissue. It was also found that the overexpression of EZH2 suppressed the expression of Collagen II, aggrecan and Sox-9, and promoted the expression of ADTAMTS5 and MMP13 in rat endplate chondrocytes (EPCs), which could be reversed by EZH2 silencing. The correlation between EZH2 and Sox-9 was further explored, while overexpression of Sox-9 could reverse the effect of EZH2 in rat EPCs. Moreover, inhibition of EZH2 upregulated the level of Sox-9 by demethylating H3K27me3 at Sox-9 promoter sites, revealing the regulatory mechanism of EZH2 on Sox-9. Meanwhile, puncture-induced rat models showed that EZH2 knockdown exerted a protective effect on CEP and disc degeneration. INTERPRETATION: This study reveals that EZH2 inhibition is a promising strategy for mitigating the symptoms and progression of IVDD. FUNDING: This study was funded by the Natural Science Foundation of Zhejiang Province (Y16H060034). Authors declare that the funders had no involvement in the study design, data analysis and interpretation of the results.

Cyanidin ameliorates the progression of osteoarthritis via the Sirt6/NF-κB axis in vitro and in vivo.

Osteoarthritis (OA) is the most prevalent form of human arthritis which is characterized by the degradation of cartilage and inflammation. As a rare Sirt6 activator, cyanidin is the major component of anthocyanins commonly found in the Mediterranean diet, and increasing evidence has shown that cyanidin exhibits anti-inflammatory effects in a variety of diseases. However, the anti-inflammatory effects of cyanidin on OA have not been reported. In the present study, we identified that cyanidin treatment could strongly suppress the expression of NO, PGE2, TNF-α, IL-6, iNOs, COX-2, ADAMTS5 and MMP13, and reduce the degradation of aggrecan and collagen II in IL-1ß-induced human OA chondrocytes, indicating the anti-inflammatory effect of cyanidin. Further investigation of the mechanism involved revealed that cyanidin could upregulate the Sirt6 level in a dose-dependent manner and Sirt6 silencing abolished the effect of cyanidin in IL-1ß-stimulated human OA chondrocytes, indicating a stimulatory effect of cyanidin on Sirt6 activation. Meanwhile, we found that cyanidin could inhibit the NF-κB pathway in IL-1ß-stimulated human OA chondrocytes and its effect may to some extent depend on Sirt6 activation, suggesting that cyanidin may exert a protective effect through regulating the Sirt6/NF-κB signaling axis. Moreover, the in vivo study also proved that cyanidin ameliorated the development of OA in surgical destabilization of the medial meniscus (DMM) mouse OA models. In conclusion, these results demonstrate that cyanidin may have therapeutic potential for the treatment of OA.

Vacuum Facet Phenomenon in Computed Tomography Imaging: A Sign of Instability in Degenerative Spondylolisthesis?

OBJECTIVE: The aim of the present study was to investigate the relationship between vacuum facet phenomena and lumbar instability in patients with degenerative spondylolisthesis (DS) in L4-L5. METHODS: Patients with L4-L5 DS who had both lumbosacral flexion-extension radiographs and computed tomography (CT) scans available for review from January 2016 to December 2017 were eligible for the present study. The dynamic motion index (DMI) of each patient was used to represent the percentage of slippage of L-L4 on the L5 vertebral disks on the flexion radiographs minus the percentage on the extension radiographs. The facet vacuum index refers to the average width of the facet vacuum on the left and right sides. RESULTS: A total of 67 patients with L4-L5 DS were included in the present study. Of the 67 patients, 35 had a vacuum facet phenomenon on their CT scan and 32 patients did not. The incidence of lumbar instability in the patients with a vacuum facet phenomenon was significantly greater than that in the patients without a vacuum facet phenomenon (P = 0.015). The mean DMI for the patients with a vacuum facet phenomenon was significantly greater than that for the patients without a vacuum facet phenomenon (P < 0.001). A positive linear correlation was found between the facet vacuum index and DMI for patients with a vacuum facet phenomenon (Pearson correlation coefficient, 0.597; P < 0.001). CONCLUSIONS: A linear correlation was found between the degree of segmental motion and the width of the vacuum facet phenomenon in patients with DS at L4-L5. Our study has shown that vacuum facet phenomena detected on the CT images of patients with DS are highly predictive of segmental instability.

Comparison of Hidden Blood Loss Between Three Different Surgical Approaches for Treatment of Thoracolumbar Fracture.

Purpose: To examine the hidden blood loss (HBL) in treatment of AO type A1-A3 thoracolumbar fractures with three different approaches and to explore the influential factors of HBL among patients after the surgery of internal fixation for thoracolumbar fractures. Methods: We retrospectively studied 85 patients in treatment of thoracolumbar fractures: 25 patients via percutaneous approach (Group A), 33 patients via paraspinal approach (Group B), and 27 patients via conventional open approach (Group C). The demographic information of the patients was collected. Each patient's preoperative and postoperative hematocrit were recorded and used for calculating the blood loss according to the Gross's formula. The difference of blood loss between the three groups was measured by ANOVA. And influential factors were further analyzed by multivariate linear regression analysis in each group. Results: The average HBL was 240.0 ± 65.1 mL in Group A, 313.7 ± 138.1 mL in Group B, and 382 ± 153.8 mL in Group C. There was statistical difference in the HBL between three groups (P = 0.000). However, multivariate linear regression analysis revealed that HBL of three approaches was not associated with age, gender, body mass index (BMI), percentage of height loss, percentage of height restoration, fracture type, or operation time. Conclusion: There was a substantial HBL in the treatment of thoracolumbar fractures, which was neglected by surgeons. Further investigation is necessary to study the risk factors for surgery on HBL in treatment of thoracolumbar fractures.

Comparison of the Total and Hidden Blood Loss in Patients Undergoing Open and Minimally Invasive Transforaminal Lumbar Interbody Fusion.

PURPOSE: This study examined the volume of hidden blood loss (HBL) and compared perioperative blood loss between minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) and open transforaminal lumbar interbody fusion (O-TLIF). METHODS: Forty-eight patients who were treated with MI-TLIF and 59 patients treated with O-TLIF were enrolled in this study. Patients' height, weight, and preoperative and postoperative hematocrit (Hct) were recorded and used to calculate total blood loss (TBL) according to the Gross formula. Each patient's HBL was calculated. The data were further analyzed by the Student t test and the χ2 test. RESULTS: The visible blood loss (VBL) was 186 ± 95 mL in the MI-TLIF; however, the HBL (423 ± 233 mL; 66.5 ± 16.1% of TBL) was twice the VBL. The VBL in the O-TLIF group was 471 ± 147 mL, and the HBL was 271 ± 223 mL (31.3 ± 23.9% of TBL). Although TBL in MI-TLIF (602 ± 251 mL) was less than in O-TLIF (742 ± 275 mL), the HBL was significantly higher (P < 0.01). No difference in postoperative blood loss was observed between the 2 groups. Seven and 10 patients had preoperative anemia in the MI-TLIF group and the O-TLIF group, respectively, and 32 and 45 postoperatively. CONCLUSION: HBL is seriously underestimated and accounts for a large percentage of TBL in both MI-TLIF and O-TLIF. A correct understanding of HBL can ensure patient safety and improve postoperative rehabilitation.

[Changes of contents of extracellular signal-regulated kinase in rat hepatic fibrogenesis induced by bile duct ligation].

AIM: To observe the dynamic expression of ERK1 in fibrotic rat liver. METHODS: The rat hepatic fibrosis was induced by bile duct ligation (BDL). Histopathological changes were evaluated by hematoxylin and eosin staining, and by Masson's trichrome method. ERK1 mRNA in liver was determined by reverse transcription-polymerase chain reaction (RT-PCR), while the distribution of ERK1 was assessed by immunohistochemistry. ERK1 protein was detected by using Western blotting analysis. RESULTS: With the development of hepatic fibrosis, the positive cells of ERK1 increased a lot, they were mainly distributed at portal ducts, fiber septa and around the bile ducts, vascular endothelial cells and perisinusoidal cells. Western blotting analysis results displayed that the expression of ERK1 protein were up-regulated with model course, and its levels were the highest at week 4 after operation, achieving to 3.9-fold of that in normal rat liver. ERK1 mRNA expressed in normal rat livers as well, they were up-regulated at day 2 after BDL and its level was the highest at week 4 after BDL. CONCLUSION: These data suggest that the expression of ERK1 and its mRNA can be increase greatly in fibrotic rat liver.