10.3969/j.issn.1000-3606.2013.06.015

Abstract BACKGROUND: Sodium hyaluronate is an effective treatment for osteoarthritis, but the underlying mechanism remains unclear. There is evidence that abnormal expressions of matrix metaloproteinase (MMP)-1, -3 and -9 and tissue inhibitor of metaloproteinase (TIMP)-1 and -2 show great effects on osteoarthritis. OBJECTIVE: To assess the influence of intra-articular injection of sodium hyaluronate on expressions of MMPs-1, 3, 9 and tissue inhibitor of TIMPs-1, 2 in the rabbit cartilage after osteoarthritis. METHODS: Twenty-four mature New Zealand white rabbits were divided into normal control, model, and sodium hyaluronate groups. The model and sodium hyaluronate groups underwent unilateral anterior cruciate ligament transection, and rabbits in the sodium hyaluronate group received 0.3 mL of 1% sodium hyaluronate via intra-articular injection at 4 weeks after modeling, once a week for 5 weeks. At 11 weeks folowing surgery, the rabbits were kiled and the cartilage was harvested to extract total RNA. mRNA expressions of MMPs-1, 3, 9 and TIMPs-1, 2 in the cartilage were analyzed using real-time PCR for each group. RESULTS AND CONCLUSION:Compared with the model group, the range and extent of cartilage damage was reduced in the sodium hyaluronate group (P < 0.01), and Mankin scores were noticeably decreased (P < 0.05). In the cartilage, mRNA expressions of MMPs-1, 3, 9 were enhanced and mRNA expressions of TIMPs-1, 2 were down-regulated in the model group. However, the mRNA expression levels of MMPs-1, 3, 9 and TIMPs-1, 2 in the articular cartilage were not obviously changed in the sodium hyaluronate group. These results suggest that MMPs-1, 3, 9 and TIMPs-1, 2 are involved in the progression of osteoarthritis and the therapeutic mechanism of sodium hyaluronate is not realized through the down-regulation of their expressions during development of osteoarthritis. Sodium hyaluronate for treatment of osteoarthritis is a complex process and the underlying mechanisms require further investigation.

BACKGROUND:Articular cartilage repair has been a difficulty in the clinical setting, which is mainly treated with autologous or al ogeneic osteochondral grafts, and cartilage periosteum or periosteum grafts. However, the limited source, secondary lesion and immunological rejection force some researchers to search for a novel treatment strategy, cartilage tissue engineering, that is of great significance for cartilage regeneration and repair. OBJECTIVE:To investigate the tissue-engineered scaffolds for the repair of articular cartilage defects. METHODS:The first author searched the PubMed and WanFang databases for the articles addressing tissue-engineered cartilage for articular cartilage defects published between 1991 and 2015 using the keywords“articular cartilage defect, scaffold, tissue engineered cartilage”in English and Chinese, respectively. The irrelative and repetitive literatures were excluded. RESULTS AND CONCLUSION:Final y 48 eligible literatures were enrol ed based on the inclusion and exclusion criteria. Cartilage tissue engineering possesses the advantages of control ability, little damage to tissue itself, and biological repair of injured cartilage. Tissue-engineered scaffold material is a critical factor in tissue engineering construction;therefore, it should hold biodegradability and histocompatibility. The commonly used scaffold materials include natural macromolecule materials (col agen, silk fibroin and chitosan), and synthetic polymer materials (polylactic acid and tricalcium phosphate). It is necessary to prepare composite scaffolds with high bioactivity integrate advantages of each material. The tissue engineering is bound to be a hotspot in the field of articular cartilage repair.

BACKGROUND:Osteoarthritis is a joint disease that primarily affects the cartilage. With the changes of the extracelular matrix, chondrocytes appear to have apoptosis. Vascular endothelial growth factor plays an important role in promoting endothelial cel division and proliferation and inducing angiogenesis. Hypoxia-inducible factor is a celular transcription factor and produces different reactions due to the oxygen content. Vascular endothelial growth factor and hypoxia-inducible factor are focused on inhibiting chondrocyte apoptosis. OBJECTIVE:To elaborate the effects of vascular endothelial growth factor and hypoxia-inducible factors on chondrocyte apoptosis. METHODS: Recent literatures related to chondrocyte apoptosis were summarized and analyzed. During the process of osteoarthritis, changes in vascular endothelial growth factors in chondrocytes and regulatory effects of vascular endothelial growth factor and hypoxia-inducible factor on chondrocyte apoptosis were elaborated.

BACKGROUND:In recent years, repair of articular cartilage injury has become an important field in basic medical research. Because injured articular cartilage is difficult to repair, the repair of articular cartilage injury has become a difficult hotspot.

BACKGROUND:Mesenchymal stem cels, underin vivo orin vitro specific induction conditions, can differentiate into the cartilage, muscle, tendons and so on. Clinical trials concerning mesenchymal stem cels mainly include tissue repair (such as bone, cartilage and joint repair) and treatment of heart, liver, spinal cord injury and nervous system diseases.
OBJECTIVE:To compare the biological characteristics of mesenchymal stem cels from different sources.
METHODS: PubMed and CNKI databases were retrieved for articles related to sources of mesenchymal stem cels and biological characteristics of mesenchymal stem cels published from 1987 to 2015. The retrieved articles were summarized and analyzed in the folowing aspects: cel surface marker, proliferation, differentiation, migration, and function, so as to explore the merits and demerits of mesenchymal stem cels from different sources.
RESULTS AND CONCLUSION:A difference in the proliferation ability and surface markers is found between different sources of mesenchymal stem cels. Immunological competence of mesenchymal stem cels from different sources may be correlated with their activation status, species differences, tissue sources and culture conditions, resulting the immunological competence of mesenchymal stem cels from different sources is not exact the same. In-depth understanding of the factors and mechanisms by which influence the migration of mesenchymal stem cels from different sources can enhance the migration ability of different sources of mesenchymal stem cels, and increase their efficiency in wound healing, tissue repair and regeneration treatment.

Objective To investigate the roles of protein kinase C(PKC)β_2 and PPARα in the mRNA expression of vascular endothelial growth factor(VEGF)and vascular cell adhesion molecule-1(VCAM-1)in human umbilical vein endothelial cells(HUVECs)exposed to high glucose,and to explore their relationship.Methods The HUVECs were divided into eight groups:normal glucose(NG,5 mmoL/L D-glucose)group,high glucose(HG,25 mmol/L D-ucose)group,osmotic control(L,NG+20 mmol/L L-glucose)group,normal glucose transfected with empty vector(NN,NG+AdS-null)group,high glucose transfected with PKCβ_2(HB,HG+Ad5-PKCβ_2)group,high glucose plus fenofibrate(HF,HG+40 μmol/L fenofibrate)group,and HB plus fenofibrate (HBF,HB+40μmol/L fenofibrate)group.HUVECs were incubated with fenofibrate for 20 minutes as HF20 group.All cells in various groups were cultured for 6 days.The expressions of VEGF and VCAM-1 mRNA were detected by RT-PCR.PPARα protein expression was tested by Western blot.The expression and traaslocation of PKCβ_2 protein were observed by confocal laser scanning microscopo.Results (1)HG increased VEGF and VCAM-1 mRNA expressions,with 1.91 and 1.56 folds of NG group,respectively(both P<0.05).VEGF and VCAM-1 mRNA expressions in HB group further increased,with 2.59 and 2.07 folds of NG group,respectively(both P<0.05).Fenofibrate significantly decreased VEGF and VCAM-1 mRNA expressions,with 68%and 74%of HG group,respectively(both P<0.05).There were no significant difierences in the expressiong of VEGF,VCAM-1 mRNA between HF20 and HG groups.(2)The protein expression of PPARα decreased by 20%in HG group compared with NG group,and further decreased in HB group,being 78%of HG group.Compared with HG group,PPARαexpression increased by 13%in HF group(P<0.05).(3)HG induced PKCβ_2 translocation from cytosol to nucleus and quantitative analysis showed the ratio of plasma/nuclear fluorescence intensity in HG group decreased by 37% compared with NG group(P<0.05).The PKCβ_2 translocation was more obvious in HB group than in HG group.Conclusion Hiigll glucose stimulates VEGF and VCAM-1 mRNA expressions in HUVECs via PKCβ_2 activationdependent PPARα pathway.

BACKGROUND:Stem cel transplantation has achieved good results in the treatment of cerebral ischemia, and how to reduce apoptosis of transplanted cel s has become the focus of the therapy.
OBJECTIVE:To investigate the injured effect of tumor necrosis factor alpha (TNF-α) on bone marrow mesenchymal stem cel s and its mechanism.
METHODS:Primary cultured bone marrow mesenchymal stem cel s from Sprague-Dawley rats were treated with 200μg/L TNF-αfor 6 hours. Cel vitality was assayed by MTT, and cel apoptosis was observed by Hoechst33342 staining. Apoptotic rate was detected by Annexin-V/PI double staining. Level of oxidative stress was evaluated by determination of malondialdehyde and superoxide dismutase levels. The protein expressions of phosphorylated-Akt, Akt, phosphorylated-FoxO1, FoxO1 were detected by western blot analysis.
RESULTS AND CONCLUSION:After treatment with TNF-α, the cel vitality of bone marrow mesenchymal stem cel s decreased, the apoptotic rate increased, and the cel s were arrested in the S phase. Moreover, the oxidative stress level was elevated, and the protein expression of phosphorylated-Akt and phosphorylated-FoxO1 was significantly reduced compared with the control group (P<0.05). These results suggest that TNF-αat high level contributes to the S-stage arrest, responsible for the apoptosis processes of bone marrow mesenchymal stem cel s via the Akt-FoxO1 pathway.

BACKGROUND:Studies have found that vascular endothelial growth factor and hypoxia inducible factor are involved in the development process of osteoarthritis, but their correlation is rarely reported. OBJECTIVE:To observe the expression and correlation of hypoxia inducible factor-2α and vascular endothelial growth factor in chondrocytes of articular cartilages in human osteoarthritis. METHODS: Articular cartilage specimens were colected from 50 patients with knee osteoarthritis undergoing total knee joint replacement. According to the joint Kelgren-Lawrance (K-L) X-ray grouping classification standard, there were 18 cases of K-LIII level and 32 cases of K-LIV level. Besides, articular cartilage specimens from 10 patients undergoing amputation for legs tumor or traffic accident served as control group. Hematoxylin-eosin staining, Safranin O-Fast Green staining and Mankin scoring were performed to observe and evaluate the histological characteristics of articular cartilages of each group, immunohistochemical staining was conducted to detect the expression of hypoxia inducible factor-2α and vascular endothelial growth factor in chondrocytes of articular cartilages, and their correlations were analyzed. RESULTS AND CONCLUSION:The Mankin score of K-LIV group was significantly higher than those of K-LIII group and control group. Immunohistochemical staining revealed that the number of chondrocytes with positive expression of hypoxia inducible factor-2α or vascular endothelial growth factor in K-LIV group was significantly higher than that in K-LIII group and control group (P < 0.05). The expression of hypoxia inducible factor-2α and vascular endothelial growth factor increased in chondrocytes of articular cartilages of osteoarthritis patients, and to up-regulate the expression of vascular endothelial growth factor may be the regulatory mechanism of hypoxia inducible factor-2αinthe pathogenesis of osteoarthritis.

Objective To determine the likelihood of G-protein coupled receptor 56 (GPR56 ) induces axonal development and myelination in the corpus callosum of mouse brain.Methods A total of 64 Gpr56 +/-and Gpr56 -/-mice were selected and randomly divided into two groups:Gpr56 +/-group (n=32)and Gpr56 -/-group (n=32).According to number of days after birth,each group was further divided into 4 subgroups including P7d,P14d,P21d and P28d subgroups.Levels of neurofilament-200 (NF -200)and proteolipid protein (PLP ) of myelin basic protein in corpus callosum were measured with immunohistochemistry staining and Western blot in P7d、P14d、P21d、P28d Gpr56 +/- and Gpr56 -/-mice.Gpr56 +/-and Gpr56 -/-neurons were cultured using P1 d Gpr56 +/-and Gpr56 -/-mouse brain.The lengths of Gpr56 +/- and Gpr56 -/-neuronal axon were measured and compared with Image J software. Axonal myelination in the corpus callosum of mouse brain in each group was observed under electronic microscopy and the axonal diameters between subgroups were compared.Results The levels of NF-200 and PLP in the corpus callosum in P7d、P14d、P21d、P28d Gpr56 -/-mice decreased significantly compared with Gpr56 +/- mice.The length of Gpr56 -/-neuronal axon was shortened compared with Gpr56 +/-neuronal axon.The number of myelinated axons was obviously reduced in the corpus callosum in P28d Gpr56 -/-mice.The diameter of axon in the corpus callosum of P28d Gpr56 +/-mouse is longer than that of P28d Gpr56 -/-mouse. Conclusions GPR56 may be involved in axonal development and myelination in the corpus callosum of mouse brain.