Metformin inactivates the cGAS-STING pathway through autophagy and suppresses senescence in nucleus pulposus cells.

Intervertebral disc degeneration (IVDD) is a complex process involving many factors, among which excessive senescence of nucleus pulposus cells is considered to be the main factor. Our previous study found that metformin can inhibit senescence in nucleus pulposus cells; however, the mechanism of such an action was still largely unknown. In the current study, we found that metformin inactivates the cGAS-STING pathway during oxidative stress. Furthermore, knockdown of STING (also known as STING1) suppresses senescence, indicating that metformin might exert its effect through the cGAS-STING pathway. Damaged DNA is a major inducer of the activation of the cGAS-STING pathway. Mechanistically, our study showed that DNA damage was reduced during metformin treatment; however, suppression of autophagy by 3-methyladenine (3-MA) treatment compromised the effect of metformin on DNA damage. In vivo studies also showed that 3-MA might diminish the therapeutic effect of metformin on IVDD. Taken together, our results reveal that metformin may suppress senescence via inactivating the cGAS-STING pathway through autophagy, implying a new application for metformin in cGAS-STING pathway-related diseases.

Cucurbitacin B attenuates osteoarthritis development by inhibiting NLRP3 inflammasome activation and pyroptosis through activating Nrf2/HO-1 pathway.

Osteoarthritis (OA) is a complicated joint disorder characterized by inflammation that causes joint destruction. Cucurbitacin B (CuB) is a naturally occurring triterpenoid compound derived from plants in the Cucurbitaceae family. The aim of this study is to investigate the potential role and mechanisms of CuB in a mouse model of OA. This study identified the key targets and potential pathways of CuB through network pharmacology analysis. In vivo and in vitro studies confirmed the potential mechanisms of CuB in OA. Through network pharmacology, 54 potential targets for CuB in treating OA were identified. The therapeutic potential of CuB is associated with the nod-like receptor pyrin domain 3 (NLRP3) inflammasome and pyroptosis. Molecular docking results indicate a strong binding affinity of CuB to nuclear factor erythroid 2-related factor 2 (Nrf2) and p65. In vitro experiments demonstrate that CuB effectively inhibits the expression of pro-inflammatory factors induced by interleukin-1ß (IL-1ß), including cyclooxygenase-2, inducible nitric oxide synthase, IL-1ß, and IL-18. CuB inhibits the degradation of type II collagen and aggrecan in the extracellular matrix (ECM), as well as the expression of matrix metalloproteinase-13 and a disintegrin and metalloproteinase with thrombospondin motifs-5. CuB protects cells by activating the Nrf2/hemeoxygenase-1 (HO-1) pathway and inhibiting nuclear factor-κB (NF-κB)/NLRP3 inflammasome-mediated pyroptosis. Moreover, in vivo experiments show that CuB can slow down cartilage degradation in an OA mouse model. CuB effectively prevents the progression of OA by inhibiting inflammation in chondrocytes and ECM degradation. This action is further mediated through the activation of the Nrf2/HO-1 pathway to inhibit NF-κB/NLRP3 inflammasome activation. Thus, CuB is a potential therapeutic agent for OA.

Inhibition of LRRK2 restores parkin-mediated mitophagy and attenuates intervertebral disc degeneration.

OBJECTIVE: To elucidate the role of LRRK2 in intervertebral disc degeneration (IDD) as well as its mitophagy regulation mechanism. METHODS: The expression of LRRK2 in human degenerative nucleus pulposus tissues as well as in oxidative stress-induced rat nucleus pulposus cells (NPCs) was detected by western blot. LRRK2 was knocked down in NPCs by lentivirus (LV)-shLRRK2 transfection; apoptosis and mitophagy were assessed by western blot, TUNEL assay, immunofluorescence staining and mitophagy detection assay in LRRK2-deficient NPCs under oxidative stress. After knockdown of Parkin in NPCs with siRNA transfection, apoptosis and mitophagy were further assessed. In puncture-induced rat IDD model, X-ray, MRI, hematoxylin-eosin (HE) and Safranin O-Fast green (SO) staining were performed to evaluate the therapeutic effects of LV-shLRRK2 on IDD. RESULTS: We found that the expression of LRRK2 was increased in degenerative NPCs both in vivo and in vitro. LRRK2 deficiency significantly suppressed oxidative stress-induced mitochondria-dependent apoptosis in NPCs; meanwhile, mitophagy was promoted. However, these effects were abolished by the mitophagy inhibitor, suggesting the effect of LRRK2 on apoptosis in NPCs is mitophagy-dependent. Furthermore, Parkin knockdown study showed that LRRK2 deficiency activated mitophagy by recruiting Parkin. In vivo study demonstrated that LRRK2 inhibition ameliorated IDD in rats. CONCLUSIONS: The results revealed that LRRK2 is involved in the pathogenesis of IDD, while knockdown of LRRK2 inhibits oxidative stress-induced apoptosis through mitophagy. Thus, inhibition of LRRK2 may be a promising therapeutic strategy for IDD.

20-Deoxyingenol alleviates osteoarthritis by activating TFEB in chondrocytes.

Osteoarthritis (OA) is an age-related degenerative disease and currently cannot be cured. Transcription factor EB (TFEB) is one of the major transcriptional factors that regulates autophagy and lysosomal biogenesis. TFEB has been shown to be an effective therapeutic target for many diseases including OA. The current study explores the therapeutic effects of 20-Deoxyingenol (20-DOI) on OA as well as its working mechanism on TFEB regulation. The in vitro study showed that 20-DOI may suppress apoptosis and senescence induced by oxidative stress in chondrocytes; it may also promote the nuclear localization of TFEB in chondrocytes. Knock-down of TFEB compromised the effects of 20-DOI on apoptosis and senescence. The in vivo study demonstrated that 20-DOI may postpone the progression of OA in mouse destabilization of the medial meniscus (DMM) model; it may also suppress apoptosis and senescence and promote the nuclear localization of TFEB in chondrocytes in vivo. This work suggests that 20-Deoxyingenol may alleviate osteoarthritis by activating TFEB in chondrocytes, while 20-DOI may become a potential drug for OA therapy.

Analysis of risk factors for loss of reduction after acromioclavicular joint dislocation treated with the suture-button.

BACKGROUND: The most commonly reported complication after acromioclavicular (AC) joint dislocation treated with the Suture-button is loss of reduction. Loss of reduction is a major factor influencing the patient's joint function and subjective satisfaction. The objective of this study is to analyze the risk factors causing loss of reduction after AC joint dislocation treated with the Suture-button. METHODS: One hundred and thirty patients with AC joint dislocation who were surgically treated the Suture-button in our hospital from February 2009 to February 2015, were recorded their age, sex, BMI, time from injury to surgery, Rockwood's classification, with or without osteoporosis, double or triple button technique, position of the clavicle tunnel, tunnel diameter, coracoid button position, alignment of the button, acromioclavicular ligament repair or not, different methods of postoperative limb immobilization, and so on. Mean comparisons or chi-square test was used for univariate analysis of the above factors, and then multivariate logistic regression analysis was performed to predict risk factors. RESULTS: Reduction was lost in 23.1% of the patients. Univariate analysis showed that button alignment, double or triple button technique, coracoid button position, position of the clavicle tunnel, acromioclavicular ligament repair or not and osteoporosis had statistically significant association with loss of reduction for AC joint (P = 0.031, 0.034, 0.000, 0.042, 0.047 and 0.000 respectively). Multivariate logistic regression analysis demonstrated that osteoporosis (P = 0.003), position of the clavicle tunnel (P = 0.032) and coracoid button position (P < 0.001) were the risk factors that significantly associated with the loss of reduction after AC joint dislocation treated with the Suture-button. CONCLUSIONS: Clavicle tunnel location using relative ratio method, accurate placement of button plate under coracoid process (inside or outside deviation <20°), various reinforcement operations for patients with osteoporosis are important factors in preventing loss of reduction.

Minimally invasive procedure of acute acromioclavicular joint dislocation: one suture-button device versus two suture-button devices.

The purpose of this study was to assess the clinical results of patients treated with either one suture-button device or two suture-button devices for acute acromioclavicular (AC) joint dislocations. Eighty patients were randomized to operative stabilization either by one suture-button device (OSB, 40) or by two suture-button devices (TSB, 40). Postoperative complications, the Constant, VAS and SST scores, patient subjective satisfaction result were reviewed. The total incidence of complications was similar in both groups (16/40 vs. 17/40, P =0 .820). There were no significant differences in the length of hospitalization, the Constant, VAS and SST scores, and the ability to return to previous work between the two groups. However, the patients of TSB group had longer incision length, more blood loss, more operative and radiation time and more hospitalization costs (P < 0.01). The radiological evaluation showed no significant difference in the CC distance between the two groups (P = 0.557). Our results indicated that one suture-button device could achieve the same good radiological and clinical results as two suture-button devices did.

Acute acromioclavicular joint dislocation treated with tightrope : Mini-open versus percutaneous stabilization.

The purpose of this study was to compare prospecti- vely the radiographic and clinical results of patients treated with tightrope through either mini-open or percutaneous stabilization for acute AC joint injuries. Eighty patients were included in this study and were randomly divided into two groups. Group A included 40 injuries treated with mini-open repair. Group B consisted of 40 injuries treated with percutaneous stabilization. Demographic and clinical data were comparable between the two groups before surgery (P>0.05). Peri-operative data, complications and clinical outcomes between the two groups were compared. The average follow-up time of Group A, was 26.5±4.3 months and Group B, was 25.2±5.6 months (P>0.05). The mean operative time was 63.2±9.6 minutes and 45.6±7.1 minutes, and the mean incision length was 6.0±1.5 cm and 4.0±0.8 cm, respectively. The operative time and incision length were significantly longer in Group A (both P<0.05). However, the radiological assessment revealed no significant difference in the coracoclavicular (CC) distance between the two groups (P>0.05). The rate of loss of reduction in the Group A was similar to that in Group B (6/40 vs. 5/40, P>0.05). Both methods were efficient methods for acute AC joint dislocation. However, percutaneous fixation had the advantages of a shorter surgical time and smaller incision length.

Management of pin tract infection in pediatric supracondylar humerus fractures: a comparative study of three methods.

The objective of this study was to prospectively compare the incidence of pin tract infection in pediatric supracondylar humerus fractures managed with pin care daily or every other day or weekly. We hypothesized that there were some differences between these three methods. From June 2012 to May 2015, 135 children with supracondylar humerus fractures were randomized to postoperative pin care by cleaning pin tracts daily (group A, 45 cases) or cleaning every 2 days (group B, 45 cases) or cleaning weekly (group C, 45 cases). The three groups were comparable with respect to age, gender, affected side, body mass index (BMI), fracture type, injury to surgery time, number of intraoperative percutaneous pinning, and follow-up time. We collected data on pin retention time, union time, and pin tract infection. The average follow-up time of group A was 4.5 ± 1.3 and 4.2 ± 1.6 months in group B and 4.3 ± 1.4 months in group C. The patient demographics and intraoperative variables of three groups were comparable. No significant difference between these three groups was found in union time and pin fixation time. Of the 135 children, 48 (35.6%) cases had pin tract infection. Grade I infections (Checketts-Otterburns classification) occurred around 28.9% of 270 pin and grade II around 6.7%. We found no differences between three groups as regards frequency and severity of pin tract infections (both P > 0.05). However, complain of pain was more frequent in group A than other two groups (P < 0.05). CONCLUSIONS: All of the three methods were effective for the management of pin site infection in pediatric supracondylar humerus fractures. However, excessive frequent care as well as pin care daily had the disadvantages of child's fear and parental anxiety. What is Known: • Pin site infection is a common complication after fracture fixation and bone lengthening using percutaneous pins or wires. • Closed reduction and percutaneous K-wires fixation are the mainstay of treatment in pediatric supracondylar humeral fractures. What is New: • All of the three methods were effective for the management of pin site infection. • Excessive frequent care as well as pin care daily has the disadvantages of child's fear and parental anxiety.

A comparative study of two closed reduction methods for pediatric supracondylar humeral fractures.

BACKGROUND: No randomized controlled studies have confirmed the advantages of the joystick technique over the traditional manual traction. The objective of this study was to compare the results of the joystick technique and the traditional manual traction for facilitating closed reduction of pediatric supracondylar humeral fractures. METHODS: From February 2009 to December 2012, sixty eight children were included in this study. Group A included 34 fractures reduced by the joystick technique. Group B consisted of 34 fractures reduced by the traditional manual traction. Preoperative demographic data were comparable between the two groups. The operative time, fluoroscopy time, hospitalization time, time to bone union, complications were recorded in both groups. Radiologic and functional results were assessed using the Flynn scoring system. RESULTS: Closed reduction was successfully done in all the fractures of Group A while traditional closed manipulation was successfully done in 25 fractures of Group B and 9 fractures failed. There was a significant difference between the two groups in the rate of failed closed reduction (P = 0.004). The mean operative time was 30.5 ± 9.0 and 48.2 ± 16.4 min, and the mean fluoroscopy time was 25.4 ± 10.5 s and 55.0 ± 21.2 s in Group A and Group B, respectively. Both the operative time and fluoroscopy time were significantly longer in Group B (P < 0.001 and 0.001, respectively). However, there was no significant difference in terms of the mean hospitalization time, mean union time, total complications, the Flynn scores between the two groups (P > 0.05). CONCLUSIONS: The joystick technique should be chosen to facilitate closed reduction if traditional manual traction failed to yield an acceptable reduction.

Risk factors for limb overgrowth after the application of titanium elastic nailing in the treatment of pediatric femoral fracture.

PURPOSE: The objective of this study was to discuss the risk factors of postoperative limb overgrowth after the application of titanium elastic nailing (TEN) in the treatment of pediatric femoral fractures as well as analyze the causes and provide guidance for clinical treatment. METHODS: The study included children with femoral fractures who were treated with TEN at our hospital from February 2005 to December 2009. Their age, gender, weight, cause of injury, having head trauma or not, fracture site, fracture type and nail-canal diameter (NCD) ratio were recorded. Student's t-test, chi-square test or Fisher's exact test was used for univariate analysis of the above factors, and then multivariate logistic regression analysis was used to analyze the possible risk factors in order to determine which ones are associated with limb overgrowth after the application of TEN to treat children with femoral fractures. RESULTS: Univariate analysis showed that the age, gender, weight, cause of injury, having head trauma or not, and the fracture site did not have a statistically significant association with limb overgrowth (P = 0.741, 0.900, 0.253, 0.739, 0.967 and 0.105, respectively). The fracture type and NCD ratio were significantly associated with limb overgrowth (P = 0.003 and 0.000, respectively). Multivariate logistic regression analysis demonstrated that the fracture type (P = 0.021, OR = 2.757) and NCD ratio (P = 0.002, OR = 2.422) were independent risk factors for limb overgrowth. CONCLUSIONS: The main factors affecting postoperative limb overgrowth are the fracture type and NCD ratio. In order to avoid limb overgrowth, unstable fractures should be fixed as firmly as possible, and the NCD ratio should be ≥0.8.

A comparative study of less invasive stabilization system and titanium elastic nailing for subtrochanteric femur fractures in older children.

The objective of this study was to compare prospectively the complications and the radiographic and clinical outcomes of reverse less invasive stabilization system (LISS) and titanium elastic nailing (TEN) for the treatment of subtrochanteric femur fractures in older children. From April 2004 to February 2012, 52 children aged from 10 to 15 years old with subtrochanteric fractures were included in this study. 26 patients were treated with reverse LISS (LISS group) and 26 children treated with titanium elastic nails (TEN group) respectively. Perioperative care was standardized. Surgical time, blood loss, length of hospitalization, hospital costs, fracture union time, full weight-bearing time and complications were analyzed. The radiologic results as well as hip functional outcomes were evaluated. The average follow-up time of LISS group was 36.5±9.3 months and TEN group was 40.2±10.6 months. No significant difference between these two groups was found in union time, full weight-bearing time and average length of hospitalization. However, the patients of LISS group had longer operation time (60.0±10.6 min vs. 40.5±7.4 min, p<0.01), more blood loss (130.0±45.0 ml vs. 15.5±10.2 ml, p<0.01), and more hospital costs (25000±700 RMB vs. 10800±500 RMB, p<0.01). The overall complication rate was significantly higher in the LISS group than in the TEN group (12/26 vs. 5/26, p=0.039). There was no significant difference between the two groups in terms of early and late radiological results. Using the Sanders score system, there were 13 excellent, 6 good and 7 fair results in the LISS group compared with 22 excellent and 4 good results in the TEN group. The excellent and good rate was significantly different between the two groups (p=0.010). Our results indicated that TEN fixation of subtrochanteric femur fractures in older children was associated with better function scores and a lower overall complication rate when compared with reverse LISS.

Management of distal third tibial fractures: comparison of combined internal and external fixation with minimally invasive percutaneous plate osteosynthesis.

PURPOSE: The objective of this study was to compare combined internal and external fixation (CIEF) with minimally invasive percutaneous plate osteosynthesis (MIPPO) in the treatment of distal third tibial fractures, and explore the benefits and defects of these two techniques. METHODS: From April 2004 to February 2012, a total of 44 patients were randomised to operative stabilisation either by two closed titanium elastic nails combined with an external fixator (CIEF, 22) or by minimally invasive percutaneous osteosynthesis with a locking plate (MIPPO, 22). Pre-operative variables included the patients' age, sex, fracture side, cause of injury, Tscherne classification of soft tissue injury, fracture pattern, presence of open fracture and interval from injury to surgery. Peri-operative variables were the operating time and the radiation time. Postoperative variables were wound problems, bone union time, time of recovery to work, the functional American Orthopaedic Foot and Ankle surgery (AOFAS) score and removal of hardware. RESULTS: There was no significant difference in the time to union, the time of recovery to work, function, alignment and total AOFAS scores between the two groups (P = 0.704, 0.835, 0.551, 0.716 and 0.212, respectively). The mean operating time and radiation time were longer in the MIPPO group than in the CIEF group (85.3 ± 12.5 vs. 73.2 ± 12.0 minutes, P = 0.002, and 3.1 ± 1.5 vs. 2.1 ± 1.2 minutes, P = 0.019, respectively). Wound complications were more common in the MIPPO group (18.2% vs. 0% with CIEF, P = 0.105). There was a trend for patients with MIPPO to have a higher incidence of ankle pain (31.8% vs. 9.1% with CIEF, P = 0.135). Painful implants were removed in 31.8% of patients with MIPPO versus 9.1% with CIEF (P = 0.135). Of the 165 self-tapping locking screws of the locking plates seven (four patients) were removed with some difficulty because of stripping of the hexagonal recess. CONCLUSIONS: Our results indicated that both CIEF and MIPPO were all efficient methods for treating distal third tibial fractures. However, CIEF had the advantages of a shorter operating and radiation time, less wound complication and ankle pain, less secondary operations for implant removal and easier removal of the implants.

Sipeimine ameliorates osteoarthritis progression by suppression of NLRP3 inflammasome-mediated pyroptosis through inhibition of PI3K/AKT/NF-κB pathway: An in vitro and in vivo study.

Background: Osteoarthritis (OA) is a chronic and degenerative condition that persists and progresses over time. Sipeimine (Sip), a steroidal alkaloid derived from Fritillariae Cirrhosae Bulbus, has attracted considerable attention due to its exceptional anti-inflammatory, analgesic, antioxidant, and anti-cancer characteristics. However, Sip's effects on OA and its mechanism still need further research. Methods: This study utilized network pharmacology to identify initial targets for Sip. Functional associations of Sip in OA were clarified through Gene Ontology (GO) enrichment analysis, bioinformatically analyzing a list of targets. Subsequently, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis assessed pathways linked to Sip's therapeutic efficacy in OA. Molecular docking techniques explored Sip's binding affinity with key targets. In vitro experiments assessed Sip's impact on lipopolysaccharide (LPS)-induced pro-inflammatory factors and its protective effects on collagen-II and aggrecan degradation within the extracellular matrix (ECM). Western blotting and fluorescence analyses were conducted to determine Sip-mediated signaling pathways. Moreover, in vivo experiments using a mouse OA model validated Sip's therapeutic efficacy. Results: The results from network pharmacology revealed a total of 57 candidate targets for Sip in OA treatment. GO enrichment analysis demonstrated a robust correlation between Sip and inflammatory response, response to LPS and NF-κB-inducing kinase activity in OA. KEGG enrichment analysis highlighted the significance of NF-κB and PI3K-AKT pathways in Sip's therapeutic potential for OA. Furthermore, molecular docking results demonstrated Sip's robust binding affinity with p65 and PI3K. In vitro experiments demonstrated Sip's effectively suppressed the expression of pro-inflammatory factors induced by LPS, such as COX-2, iNOS, IL-1ß, and IL-18. Besides, Sip counteracted the degradation of collagen-II and aggrecan within the ECM and the expression of MMP-13 and ADAMTS-5 mediated by LPS. The safeguarding effects of Sip were ascribed to its inhibition of PI3K/AKT/NF-κB pathway and NLRP3 inflammasome mediated pyroptosis. Additionally, in vivo experiments revealed that Sip could alleviate the subchondral remodeling, cartilage degeneration, synovitis as well as ECM degradation a mouse model of OA. Conclusion: Sip exhibited potential in attenuating OA progression by suppressing the PI3K/AKT/NF-κB pathway, consequently inhibiting the activation of NLRP3 inflammasome and pyroptosis. The translational potential statement: The translational potential of this articleThis study provides a biological rationale for the use of Sip as a potential candidate for OA treatment, provide a new concept for the cartilage targeted application of natural compounds.

Management of hangman's fracture with percutaneous transpedicular screw fixation.

PURPOSE: This study describes a percutaneous technique for C2 transpedicular screw fixation and evaluates its safety and efficacy in the treatment of patients with hangman's fracture. METHODS: Ten patients with hangman's fracture were treated by percutaneous C2 transpedicular screw fixation. There are six males and four females, who were, based on the classification of Levine and Edwards, sorted as follows: type I fracture, three cases; type II, five cases; type IIa, two cases. The causes of injury were road traffic accident in six patients and falling injury in four patients. Other associated lesions included rib fractures (7 patients), head injuries (4 patients), and fractures of extremities (6 patients). RESULTS: The new technique was performed successfully in all cases. The average operation time was 98 min (range 60-130 min) and the estimated blood loss was 25 ml (range 15-40 ml). No complications such as vascular or neural structures injuries were found intraoperatively. Postoperative CT scans demonstrated that 17 (85 %) of 20 screws were placed satisfactorily, and 3 (15 %) screws showed perforations of the pedicle wall (<2 mm). These patients were asymptomatic and no further intervention was required postoperatively. After 8-25 months follow-up (mean 15.3 months), solid fusion was demonstrated by computed tomography. All cases got well-sagittal alignment and no angulation or dislocation was found at the segment of C2-C3. There was no loss of fixation. Clinical examination showed a full range of motion in the neck in all patients. CONCLUSIONS: The fluoroscopically assisted percutaneous C2 transpedicular screw fixation method is a technically feasible and minimally invasive technique for hangman's fracture.

20-Deoxyingenol alleviates intervertebral disc degeneration by activating TFEB in nucleus pulposus cells.

Intervertebral disc degeneration (IVDD) is a prevalent degenerative disease with significant adverse implications for patients' quality of life and socioeconomic status. Although the precise etiology of IVDD remains elusive, the senescence of nucleus pulposus cells is recognized as the primary pathogenic factor of IVDD; however, drugs that may targetedly inhibit senescence are still lacking. In the current study, we evaluated the small-molecule active drug 20-Deoxyingenol(20-DOI) for its effects on combating senescence and delaying the progression of IVDD. In vitro experiments revealed that the administration of 20-DOI displayed inhibitory effects on senescence and the senescence-related cGAS-STING pathway of nucleus pulposus cells. Additionally, it exhibited the ability to enhance lysosome activity and promote autophagy flux within nucleus pulposus cells. Subsequent investigations elucidated that the inhibitory impact of 20-DOI on nucleus pulposus cell senescence was mediated through the autophagy-lysosome pathway. This effect was diminished in the presence of transcription factor EB (TFEB) small hairpin RNA (shRNA), thereby confirming the regulatory role of 20-DOI on the autophagy-lysosome pathway and senescence through TFEB. In vivo experiments demonstrated that 20-DOI effectively impeded the progression ofIVDD in rats. These findings collectively illustrate that 20-DOI may facilitate the autophagy-lysosomal pathway by activating TFEB, thereby suppressing the senescence in nucleus pulposus cells, thus suggesting 20-DOI as a promising therapeutic approach for IVDD.

Immune-responsive gene 1/itaconate activates nuclear factor erythroid 2-related factor 2 in microglia to protect against spinal cord injury in mice.

The pathophysiology of spinal cord injury (SCI) involves primary injury and secondary injury. Secondary injury is a major target for SCI therapy, whereas microglia play an important role in secondary injury. The immunoresponsive gene 1 (Irg-1) has been recorded as one of the most significantly upregulated genes in SCI tissues in gene chip data; however, its role in SCI remains unclear. This study aims to illustrate the role of Irg-1 as well as its regulated metabolite itaconate in SCI. It was demonstrated that the expression of Irg-1 was increased in spinal cord tissues in mice as well as in microglia stimulated by lipopolysaccharides (LPS). It was also shown that overexpression of Irg-1 may suppress LPS-induced inflammation in microglia, while these protective effects were attenuated by Nrf2 silencing. In vivo, overexpression of Irg-1 was shown to suppress neuroinflammation and improve motor function recovery. Furthermore, treatment of microglia with itaconate demonstrated similar inflammation suppressive effects as Irg-1 overexpression in vitro and improved motor function recovery in vivo. In conclusion, the current study shows that Irg-1 and itaconate are involved in the recovery process of SCI, either Irg-1 overexpression or itaconate treatment may provide a promising strategy for the treatment of SCI.

Itaconate attenuates osteoarthritis by inhibiting STING/NF-κB axis in chondrocytes and promoting M2 polarization in macrophages.

Osteoarthritis (OA) is a progressive joint disease characterized by the degradation and destruction of articular cartilage, which is involved with pathological microenvironmental alterations induced by damaged chondrocytes and inflammatory macrophages. However, the current therapies cannot effectively alleviate the progression of OA. Our previous studies have shown that the pathological process of OA progression is accompanied by DNA damage, and inhibition of STING, a key molecule in DNA damage, may become a potential method for the treatment of OA. Itaconate, a metabolite highly expressed in macrophages under inflammatory conditions, has shown a wide range of anti-inflammatory effects, but its effect on OA and its underlying mechanism has not yet been studied. In this study, we found that exogenous supplementation of itaconate can activate Nrf2, and accordingly inhibit the STING-dependent NF-κB pathway, thereby alleviating the inflammation, ECM degeneration and senescence of chondrocytes stimulated by IL-1ß. In addition, itaconate can regulate the polarization of RAW264.7 macrophages, further reducing the apoptosis of chondrocytes. In vivo, intra-articular injection of itaconate reduces the degradation of cartilage and inflammation of synovial membrane in the mouse OA model. In conclusion, the present work suggests that exogenous supplementation of itaconate inhibits the inflammation, senescence and ECM degeneration of chondrocytes through the Nrf2/STING/NF-κB axis and regulates the polarization of synovial macrophages, thereby ameliorating the progression of OA, which supports that itaconate as a potential drug for the treatment of OA.

Position of Coracoid Button Predicts Loss of Reduction in Acromioclavicular Joint Dislocation Patients Treated With the Suture-Button.

BACKGROUND: Loss of reduction is the most common complication after acromioclavicular (AC) joint dislocation treated with the suture-button. Some predictors of it are known, but finding new predictors is an ongoing process. In this study, we evaluate the importance of the position of the coracoid button. MATERIALS AND METHODS: Between April 2010 and February 2017, 186 patients with AC joint dislocation were identified. All patients were managed with the same surgical technique and postoperative protocol. The position of the coracoid button was determined immediately after surgery by anterior-posterior views of the operated shoulder and was classified as medial (Group A, 42 cases), central (Group B, 85 cases) and lateral (Group C, 59 cases) positions. The main outcome measurement was loss of reduction. The main analysis was the association between the coracoid button position and loss of reduction. RESULTS: No significant difference was found in the baseline characteristics among 3 groups. During follow-up, there were 15 cases (35.7%) developing loss of reduction in Group A, 5 cases (5.9%) in Group B and 26 cases (44.1%) in Group C. The rate of loss of reduction in Groups A and C were higher than that in Group B (p < .05). Moreover, there was no significant difference in the rate of reduction loss between lateral and medial positions of the coracoid buttons (p > .05). CONCLUSION: Our results indicated that both lateral and medial positions of the coracoid buttons could predict loss of reduction in AC joint dislocation patients treated with the suture-button.

Betulin Alleviates the Inflammatory Response in Mouse Chondrocytes and Ameliorates Osteoarthritis via AKT/Nrf2/HO-1/NF-κB Axis.

Osteoarthritis (OA) is a common degenerative joint disease featuring the degeneration, destruction, and ossification of cartilage. Inflammation which may facilitate OA occurrence and development is considered as the main pathological factor. Betulin, a natural product extracted from birch bark, has been commonly used for inflammation treatment; however, its role in OA remains unclear. This study is aimed to explore whether betulin can suppress IL-1ß-induced inflammation in chondrocytes and alleviate OA in vitro and in vivo. In in vitro studies, the generation of pro-inflammatory factors, such as interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), prostaglandin E2 (PGE2), and nitric oxide (NO), was assessed using the enzyme-linked immunosorbent assay (ELISA) and Griess reaction. As revealed by results, betulin inhibited the expression of pro-inflammatory mediators. In addition, the protein expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), matrix metalloproteinase (MMP-13), thrombospondin motifs 5 (ADAMTS5), Collagen II, and Aggrecan were quantified using Western blot analysis. We found that betulin could inhibit the generation of COX-2 and iNOS induced by IL-1ß, indicating that betulin has anti-inflammatory effects in chondrocytes. Furthermore, betulin downregulates the expression of MMP-13 and ADAMTS-5 and upregulates the expression of Collagen II and Aggrecan, indicating that it can inhibit the degradation of the extracellular matrix. In mechanism, betulin activated the AKT/Nrf2 pathway and inhibited the phosphorylation of p65. In in vivo studies, administration of betulin in vivo could inhibit cartilage destruction and inflammatory progression. Therefore, these findings suggest that betulin may alleviate IL-1ß-induced OA via the AKT/Nrf2/HO-1/NF-κB signal axis, and betulin may be a potential drug for the treatment of OA.

RNA-binding protein HuR suppresses senescence through Atg7 mediated autophagy activation in diabetic intervertebral disc degeneration.

OBJECTIVES: Diabetes is a risk factor for intervertebral disc degeneration (IVDD). Studies have demonstrated that diabetes may affect IVDD through transcriptional regulation; however, whether post-transcriptional regulation is involved in diabetic IVDD (DB-IVDD) is still unknown. This study was performed to illustrate the role of HuR, an RNA-binding protein, in DB-IVDD development and its mechanism. MATERIALS AND METHODS: The expression of HuR was evaluated in nucleus pulposus (NP) tissues from diabetic IVDD patients and in high glucose-treated NP cells. Senescence and autophagy were assessed in HuR over-expressing and downregulation NP cells. The mRNAs that were regulated by HuR were screened, and immunoprecipitation was applied to confirm the regulation of HuR on targeted mRNAs. RESULTS: The results showed that the expression of HuR was decreased in diabetic NP tissues and high glucose-treated NP cells. Downregulation of HuR may lead to increased senescence in high glucose-treated NP cells, while autophagy activation attenuates senescence in HuR deficient NP cells. Mechanistic study showed that HuR prompted Atg7 mRNA stability via binding to the AU-rich elements. Furthermore, overexpression of Atg7, but not HuR, may ameliorate DB-IVDD in rats in vivo. CONCLUSIONS: In conclusion, HuR may suppress senescence through autophagy activation via stabilizing Atg7 in diabetic NP cells; while Atg7, but not HuR, may serve as a potential therapeutic target for DB-IVDD.