The use of a transolecranon pin joystick technique in the treatment of multidirectionally unstable supracondylar humeral fractures in children.

Multidirectionally unstable supracondylar humeral fractures cause severe instability in both flexion and extension movements. The traditional closed reduction often fails to overcome this lack of stability. The aim of this study is to use a closed reduction technique with a transolecranon pin to achieve temporary stability. From 35 pediatric multidirectionally unstable supracondylar humeral fractures hospitalized between March 2012 and March 2018 at our hospital, 23 fractures (65.7%) were treated with closed reduction and percutaneous pinning (CRPP) (group 1) and the remaining twelve fractures (34.3%) were treated utilizing a transolecranon pin joystick technique of CRPP (group 2). Both groups were followed over 16 weeks. The outcomes of our analysis included surgical time, times of fluoroscopy, Baumann angle, postoperative range of motion and complications. The surgical time and times of fluoroscopy were significantly shorter for patients in group 2 when compared with group 1 (P < 0.05). All cases showed restoration of the normal anterior humeral line-capitellar relationship. However, the quality of reduction on the anteroposterior radiographic view was significantly better for patients in group 2 than that of group 1 (P < 0.05). No immediate postoperative complications were observed. The range of motion was similar in both groups during the last follow-up appointment. A transolecranon pin is a safe and effective method for closed reduction of multidirectionally unstable supracondylar humeral fractures in children. The joystick technique can shorten surgical time and improve quality of reduction with no increasing risk of complications. Level of evidence: level III.

Roles of microRNA-22 in Suppressing Proliferation and Promoting Sensitivity of Osteosarcoma Cells via Metadherin-mediated Autophagy.

OBJECTIVE: To analyze the effect of microRNA-22 on autophagy and proliferation and to investigate the underlying molecular mechanism of osteosarcoma cell chemotherapy sensitivity. METHODS: MG-63 cells were divided into four groups, including a control group, a negative control (NC) group, a cisplatin group, and a cisplatin + miR-22 group. Proliferation of MG-63 cells that had been treated with cisplatin and transfected with miR-22 mimics was determined using MTT assay and colony formation assay. We assessed the degree of autophagy using flow cytometry through cellular staining of the autophagy lysosomal marker monodansylcadaverine (MDC). The effect of microRNA-22 on autophagy was observed along with the expression levels of Beclin1, LC3, metadherin (MTDH) and ATG5 by western blot and quantitative reverse transcription polymerase chain reaction (qRT-PCR). Luciferase reporter assay revealed the targeted binding site between miR-22 and the 3'-untranslated region (3'-UTR) of MTDH mRNA. Western blot and qRT-PCR were used to explore the level of MTDH in the control group, the NC group, the cisplatin group, and the miR-22 group for 6, 12, and 24 h. RESULTS: In the in vitro study, the MTT results indicated that the MG-63 cells with overexpression of miR-22 exhibited a significant decline in the proliferation capacity compared with the control group (0.513 ± 0.001, P < 0.0005). Similar to the MTT results, MG-63 cells that were transfected with miR-22 mimic (101.0 ± 10.58) formed fewer colonies compared with the cisplatin group (129.7 ± 4.163). MDC staining revealed that miR-22-overexpressing osteosarcoma (OS) cells treated with cisplatin showed a significant decrease in the expression of autophagy (7.747 ± 0.117, P < 0.0001). Our data revealed that miR-22 could regulate not only autophagy but also proliferation in the chemosensitivity of osteosarcoma cells. We found that miR-22 sensitized osteosarcoma cells to cisplatin treatment by regulating autophagy-related genes. In addition, Luciferase Reporter Assay revealed that miR-22 negatively regulated autophagy through direct targeting of MTDH. We performed western blot analysis to detect the MTDH expression level. The results revealed that the overexpression of miR-22 obviously decreased the expression of MTDH (1.081 ± 0.023, P < 0.001). CONCLUSION: Inhibition of miR-22 ameliorated the anticancer drug-induced cell proliferation decrease in osteosarcoma cells. MTDH was identified as the miR-22 target in OS cells and MTDH-triggered autophagy played a key function in the miR-22-associated chemotherapy sensitivity.

BMP-7 accelerates the differentiation of rabbit mesenchymal stem cells into cartilage through the Wnt/ß-catenin pathway.

Mesenchymal stem cells (MSCs) are able to differentiate into adipocytes, chondroblasts or cartilage under different stimulation conditions. Identifying a mechanism that triggers the differentiation of MSCs into cartilage may help the development of novel therapeutic approaches for heterotopic ossification, the pathological formation of lamellar bone in soft tissue outside the skeleton that may lead to debilitating immobility. Bone morphogenetic proteins (BMPs), including BMP-7, are the most potent growth factors for enhancing bone formation. The current study aimed to understand the potential involvement of the Wnt/ß-catenin signaling pathway in the BMP-7-induced growth of rabbit MSCs (rMSCs). Different concentrations of BMP-7 were applied to cultured rMSCs, and proliferation was evaluated by MTT assay. Changes in the phosphorylation state of glycogen synthase kinase (GSK)-3ß, in addition to the expression levels of alkaline phosphatase, ß-catenin and runt-related transcription factor 2 were observed by western blot analysis. Following treatment with BMP-7, the phosphorylation of GSK-3ß was stimulated and the expression of ß-catenin, ALP and Runx2 was increased. Furthermore, inhibiting ß-catenin signaling with XAV-939 suppressed the BMP-7-mediated changes. The results indicated that the BMP-7-induced differentiation of rMSCs into cartilage was promoted primarily by the Wnt/ß-catenin pathway.

Altered Chondrocyte Apoptosis Status in Developmental Hip Dysplasia in Rabbits.

BACKGROUND: Developmental dysplasia of the hip (DDH) is an important factor leading to early adult osteoarthritis. Chondrocyte apoptosis has been proven to be an important factor causing osteoarthritis. AIMS: The current study aims to explore whether a rabbit model of developmental dysplasia of the hip through cast immobilization in the legs results in chondrocyte apoptosis. STUDY DESIGN: Animal experimentation. METHODS: Thirty-two New Zealand white rabbits were divided in three groups with cast plaster-induced dislocation at 2, 4 and 6 weeks. The contralateral hip joint was utilized as a control group. Ten rabbits in each group were sacrificed, and hip specimens were obtained. Bcl-2/Bax, cleaved caspase-3 and cleaved caspase-8 expression were examined by western blot analysis. Chondrocyte apoptosis was analyzed through transmission electron microscopy (TEM) and TUNEL analysis. All experiments were repeated at least three times. RESULTS: In the experimental group, Bcl-2/Bax, cleaved caspase-3 and cleaved caspase-8 expression were significantly altered. The Bcl-2/Bax ratio decreased with time (all p<0.01), whereas levels of cleaved caspase-3 (p<0.01 and p<0.05) and cleaved caspase-8 (all p<0.05) gradually increased. Chondrocyte apoptosis was observed through transmission electron microscopy (TEM) and TUNEL analysis (p<0.05 at 4 weeks and p<0.01 at 6 weeks). CONCLUSION: Prolonged immobilization of rabbit hip caused chondrocyte apoptosis. Reduction of the hip joint may protect chondrocytes from apoptosis, thus preventing secondary osteoarthritis.

Decreased local and systematic matrix Gla protein (MGP) expression and its link to radiographic progression in ankylosing spondylitis patients.

BACKGROUND: Decreased serum levels of uncarboxylated matrix Gla-protein (ucMGP) have been detected in Ankylosing Spondylitis (AS) patients. The current study was to investigate the expression of MGP in AS tissues as well as the relationship between serum ucMGP (an inactive form of MGP) levels and radiographic severity in AS patients. METHODS: Local MGP expression were assessed by Western blot and RT-PCR in hip synovial tissues from patients with AS and control subjects. In addition, the serum level of ucMGP was assessed by enzyme-linked immunosorbent assay in 68 healthy subjects and 62 patients with AS. The radiographic progression of AS was classified according to the radiographic events of modified New York Criteria for sacroiliac joint evaluation and modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) system for spine assessment. RESULTS: MGP expression was downregulated in AS patients compared to controls in hip tissues. Decreased levels of ucMGP in serum were found in AS patients compared with healthy controls. ucMGP levels in serum of AS patients were significantly negatively correlated with the disease radiographic severity evaluated by modified New York grading criteria (r = -0.293, p = 0.045) and mSASSS system (r = -0.361, p = 0.03). CONCLUSIONS: MGP expression is impaired in patients with AS. A low serum level of ucMGP in the setting of AS is linked to increased structural damage, emphasizing the role of MGP in the suppression of new bone formation.