BACKGROUND: Tissue engineering development brings a hope for articular cartilage defect repair. Current studies have demonstrated that bone marrow mesenchymal stem cells (MSCs) are the best cell source to repair full-thickness cartilage defects.OBJECTIVE: To induce MSCs to differentiate into chondrocytes with Ad-hTGF-pi in pellet culture system in vitro and identify the differentiated cells.DESIGN, TIME AND SETTING: Repetitive cellular measurements were performed at the Central Laboratory of Xinqiao Hospital,Third Military Medical University of Chinese PLA from June 2007 to January 2008.MATERIALS: Japanese rabbits, 2 months old, were provided by the Laboratory Animal Center of Third Military Medical University of Chinese PLA.METHODS: The rabbit MSCs were isolated, cultured and expanded in vitro. After transacted with Ad-hTGF-β1, the cells were cultured in pellet culture system. Chondrogenic differentiation was evaluated by histological, immunohistochemical and RT-PCR techniques.MAIN OUTCOME MEASURES: Cell morphological changes were observed by histological staining; proteoglycan and type Ⅱ collagen expression was detected by immunohistochemical and RT-PCR techniques.RESULTS: The induced cells exhibited a chondrocyte-like morphology by histological staining. Immunohistochemical and RT-PCR results showed that proteoglycan and type Ⅱ collagen were expressed in the induced cells.CONCLUSION: Bone marrow MSCs cultured in pellet culture system can differentiate into chondrocytes under the induction of Ad-hTGF-β1.

BACKGROUND:Tissue engineering development brings a hope for articular cartilage defect repair.Current studies have demonstrated that bone marrow mesenchymal stem cells (MSCs) are the best cell source to repair full-thickness cartilage defects.OBJECTIVE:To induce MSCs to differentiate into chondrocytes with Ad-hTGF-?1 in pellet culture system in vitro and identify the differentiated cells.DESIGN,TIME AND SETTING:Repetitive cellular measurements were performed at the Central Laboratory of Xinqiao Hospital,Third Military Medical University of Chinese PLA from June 2007 to January 2008.MATERIALS:Japanese rabbits,2 months old,were provided by the Laboratory Animal Center of Third Military Medical University of Chinese PLA.METHODS:The rabbit MSCs were isolated,cultured and expanded in vitro.After transfected with Ad-hTGF-?1,the cells were cultured in pellet culture system.Chondrogenic differentiation was evaluated by histological,immunohistochemical and RT-PCR techniques.MAIN OUTCOME MEASURES:Cell morphological changes were observed by histological staining;proteoglycan and type II collagen expression was detected by immunohistochemical and RT-PCR techniques.RESULTS:The induced cells exhibited a chondrocyte-like morphology by histological staining.Immunohistochemical and RT-PCR results showed that proteoglycan and type II collagen were expressed in the induced cells.CONCLUSION:Bone marrow MSCs cultured in pellet culture system can differentiate into chondrocytes under the induction of Ad-hTGF-?1.

Objective To investigate the immunologic properties of osteogenic differentiated bone mesenchymal stem cells (BMSCs). Methods BMSCs were isolated from normal volunteers and induced in osteogenic medium for two weeks. Then,non-differentiated/osteogenic differentiated BMSCs were co-cultured with allogenic T cells and phytohemagglutinin (PHA).The proliferation of T cells was examined by MTT method.The concentrations of TGF-β1 in osteogenic differentiated BMSCs supernatants at week 2 and mixed lymphocytes reaction (MLR) supernatants at day 5 were determined by ELISA.Also,anti-TGF-β antibody was added into the MLR to detect the response of the mixed T cells. Results Non-differentiated and osteogenic differentiated BMSCs did not induce proliferation of the allogeneic T cells but both suppressed the proliferation of the T cells mediated by PHA.The TGF-β1 concentrations had significant elevation in the MLR.Anti-TGF-β antibody could counteract the immunosuppressive function of the osteogenic differentiated BMSCs. Conclusion Osteogenic differentiated BMSCs possess low immunogenicity and immunosuppressive property.

BACKGROUND:Fractures can induce bone cel hypoxia, and remarkably reduce the oxygen tension in cels. Hypoxia-inducible factor-2α is a key oxygen-dependent transcriptional activator to regulate the body function under hypoxia and mediate the release of various inflammatory factors after fractures.
OBJECTIVE:To explore the role of Laquinimod in expression and function of hypoxia-inducible factor-2αin osteoblasts.
METHODS: Mouse osteoblasts MC3T3-E1 (clone 14) were pretreated with Laquinimod at various concentrations(10-100μmol/L) before hypoxia in the presence or absence of specific proteasome inhibitors MG132 or N-acetyl-leucyl-leucyl-norleucine. Then, the media were pre-conditioned in 1% or 21% oxygen tension for 1 to 24 hours.
RESULTS AND CONCLUSION: Under hypoxia, the expression of hypoxia-inducible factor-2α in osteoblasts was increased remarkably, and Laquinimod could inhibit the expression of hypoxia-inducible factor-2α and its target genes in mouse MC3T3-E1 cels. Mechanisticaly, Laquinimod promoted hypoxia-inducible factor-2α degradation in a proteasome-dependent but von Hippel-Lindau protein-independent manner. Importantly, we found that Laquinimod disrupted the interaction between hypoxia-inducible factor-2α and its chaperone heat shock protein 90, but promoted the interaction between hypoxia-inducible factor-2α and the receptor of activated protein kinase C. These findings suggest that Laquinimod may promote the degradation of hypoxia-inducible factor-2α by affecting its folding and maturation. Laquinimod is a novel inhibitor of hypoxia-inducible factor-2α by changing its functional interaction with chaperone proteins heat shock protein 90 and receptor of activated protein kinase C.

Minimally invasive surgery has become a trend in modern orthopedic surgery,and the demand for intraoperative imaging has gradually increased.Good intraoperative imaging can assist the orthopaedic surgeon in accurately positioning the anatomy and placing the internal fixation.However,intraoperative imaging inevitably exposes the orthopaedic surgeon and patient to ionizing radiation,and radiation exposure can induce DNA damage and reactive oxygen species.Production results in cell damage that often leads to cell death or genomic instability leading to increased risk of various radiation-related conditions,including malignancy.Although the traditional intraoperative fluoroscopy operating room will be equipped with lead clothing and lead collar to reduce radiation exposure,it is not known whether the lead clothing and lead-covered parts are safe.Therefore,radiation safety has become an inevitable problem for orthopedic surgeons in intraoperative imaging,and how to effectively reduce and avoid unnecessary exposure to ionizing radiation is particularly important for bone surgeons and patients.This article aims to review the occupational exposure and radiation safety of intraoperative imaging in orthopaedic surgery.

Objective:To investigate the effects of three-dimensional computed tomography angiography (3D-CTA)-assisted free medial sural artery perforator flap in repairing foot wounds.Methods:A retrospective observational study was conducted. From May 2018 to August 2021, 18 patients with foot soft tissue defects who met the inclusion criteria were admitted to the Department of Spine and Trauma Orthopedics of the Yidu Central Hospital of Weifang, including 13 males and 5 females, aged 19 to 55 years, with a wound area of 4.0 cm×3.0 cm-9.0 cm×8.0 cm at admission. Before the operation, CT scanner was used to scan the area from the supracondylar femur to the middle segment of the fibula of patients, and the obtained data were extracted into the Mimics16.0 software and analyzed to determine the pre-selected perforator, and then the image data of the pre-selected perforator side were analyzed further, and the body surface projection position of the perforating point of the medial sural artery in the calf region was marked. Based on the above examination, the flap was designed and cut according to the shape and area of the patient's foot tissue defect, and the area of flaps ranged from 5.0 cm×4.0 cm to 10.0 cm×9.0 cm. The donor sites were sutured directly or covered by skin grafting. The type of perforator, the diameters of perforator at the beginning and outlet point, and the location of the outlet point of perforator of the medial sural artery were observed under 3D-CTA examination before operation and compared to see if they were consistent with the observation under intraoperative condition. The survival of the flaps after operation was recorded. During follow-up, the satisfaction of patients with the wound repair effects, the sensory recovery of the recipient flaps, the healing of the donor wound, and whether there were complications affecting limb functions were recorded. Data were statistically analyzed with Kappa consistency test and equivalence test, and the 95% confidence intervals of measurement difference of perforator diameter and outlet point position of perforator were -0.50-0.50 mm and -2.0-2.0 cm, respectively.Results:The types of medial sural artery perforators observed during operation were type Ⅰ in 3 cases, type ⅡA in 6 cases, type ⅡB in 8 cases, and type Ⅲ in 1 case, which was consistent with the results of 3D-CTA before operation (Kappa=1.00, P<0.05). The blood vessel diameter detected by 3D-CTA before operation at the beginning of perforator of medial sural artery was (1.81±0.39) mm, and the blood vessel diameter at the outlet point of the perforator was (0.83±0.21) mm, which were close to the actual intraoperative measurement of (1.83±0.43) and (0.86±0.22) mm, respectively; equivalence test showed that the 95% confidence intervals of the measurement differences of diameter of medial sural artery perforator at beginning and outlet point were -0.18-0.22 and -0.08-0.14 mm, respectively, with both P values <0.05. The preoperative 3D-CTA detected that the perforating position at the deep fascia of the perforator of the medial sural artery, namely the vertical distance with the popliteal fold was (12.2±1.4) cm, and the horizontal distance with the posterior midline was (2.6±0.7) cm, which were respectively close to the actual intraoperative measurement of (12.4±1.4) and (2.6±0.7) cm; equivalence test showed that the 95% confidence intervals of the measurement differences in the vertical distance with the popliteal fold and the horizontal distance with the posterior midline of the outlet point of medial sural artery perforator were -1.06-1.26 and -0.46-0.66 cm, respectively, with both P values <0.05. After surgery, all flaps of 18 patients survived without vascular crisis. After 1 year of follow-up, the satisfaction degree of 16 patients was excellent and 2 patients was good with the wound repair effects, with a satisfaction ratio of 16/18; the sensory recovery of flap was evaluated as S 3 in 11 cases and S 2 in 7 cases; the donor wounds healed well without obvious scar or contracture, with no effect on limb joint functions. Conclusions:The medial sural artery perforator flap achieved good results in repairing foot wound with high degree of patient satisfaction. Preoperative application of 3D-CTA can realize the standardization, systematization, and visualization of artery perforator flap.