BACKGROUND: Chondron is a basic microanatomical unit of articular cartilage. lncreasing evidence suggests that the pericellular matrix (PCM) is a distinct functional compartment in articular cartilage, influencing the metabolic, micromechanical environment, and degeneration of chondrocytes. But the precise functions and action mechanism need further investigation.OBJECTIVE: To review the literature pertinent to the morphology, function, isolation of the chondron in articular cartilage, and its degenerative events during the progression of osteoarthritis (OA).METHODS: This review summarized the articles published in the PubMed database before July 2009. In addition, recent data and figure of our laboratory on the morphology and biomechanics of chondron and chondrocyte were supplemented. RESULTS AND CONCLUSION: The PCM is primarily characterized by the presence of type Ⅵ collagen, and these components are widespread in the expansive extracellular matrix (ECM) in newborns, while in mature the components are mainly localized to a narrow pericellular zone. The three-dimensional morphology of chondron has been recently quantified in situ with fluorescence confocal microscopy, and the mechanical properties of the isolated individual chondrons and their PCM are measured using the micropipette technique and atomic force microscopy. More studies have shown that the presence of the PCM in chondrons has a profound influence on chondrocyte gene expression. At the same time, structural, histochemical and biomechanical studies indicate the chondron and their PCM may undergo degenerative processes with osteoarthritis, similar to those occurring in the ECM, Although the precise function of the PCM is unknown, increasing evidence in vivo or in vitro suggests that the PCM is a basic microanatomical unit in articular cartilage, influencing the metabolic and micromechanical environment of chondrocytes.Department of Orthopedics, the Second Hospital of Shanxi Medical University, Shanxi Key Laboratory of Bone and Soft Tissue Injury Repair,Taiyuan 030001,Shanxi Province,China

Objective To compare the accuracy of placement of ventricular shunt tube,the efficacy and complications of the neuronavigation-assisted ventriculoperitoneal shunt (group A) and traditional ventriculoperitoneal shunt (group B).Methods A retrospective study was made on 40 cases of hydrocephalus managed with neuronavigation-assisted ventriculoperitoneal shunt or ventriculoperitoneal shunt from January 2012 to June 2016.There were 18 cases [12 males,6 females;(47.5 ±8.5) years of age] in group A and 22 cases [14 males,8 females;(44.5 ± 7.5) years of age] in group B.Therapeutic effect and complications were analyzed postoperatively.The accuracy rate in ventricular end shunt placement that was free from the frontal horn of lateral ventricle and flush the Moro hole had also been studied.Results The position of ventricular shunt of all the patients were postoperative timely review of the CT view,and hospital outpatient follow-up periodical for 3-24 months after discharge from hospital.Patients with postoperative timely review of head CT and found that group A of ventricular end of the shunt tube position reach a set position in 16 cases,2 cases had not reached the set position,the accuracy rate was 88.89％.There were 8 cases in group B reach to the set position and 14 cases did not and the accuracy rate was 36.36％.After the statistical analysis there were significant differences (P ＜ 0.05).The total efficiency of A and B groups (excellent + effective) were 94.4％ and 86.4％ (P ＞ 0.05).Postoperative complications included bleeding,infection,obstruction of the shunt,excessive shunt,shunt insufficiency and so on.During follow-up,group A appeared excessive shunt in 1 case;group B incision infection in 1 case,4 cases of shunt obstruction,excessive shunt in 1 case,2 cases of deficiency of shunt.Two groups of patients were recovery well through the drainage tube pressure adjustment or set it once again.The incidence of complications in group A was 5.56％,group B was 36.36％.There was no significant difference between group A and group B (P ＞ 0.05).In group A,there was no obstruction of shunt tube,ventricular end of the shunt tube blockage occurred in 4 cases in group B,the incidence rate was 18.18％ (P ＞ 0.05).Conclusion Neuronavigation guided ventriculoperitoneal shunt placement to the accuracy of position setting has significant advantages over traditional ventriculoperitoneal shunt in the ventricular end of the shunt tube and it has some advantages in reducing postoperative complications.

Objective To explore the histological properties of isolated chondrons and chondrocytes from rabbit knee cartilage,and to determine if these properties vary with age.Methods Three groups of rabbit knees were evaluated according to different age:(1) young (2 months,n=10);(2) adult (8 months,n=10);and (3) old (31 months,n=10).The cartilage structure,proteoglycan,collagen-2,and collagen-6 content were determined by light microscopic using hematoxylin-eosin (HE),Toluidine Blue,and col-2,6 staining.The chondrons were enzymatically isolated using 0.3 g/L dispase and 0.2 g/L collagenase-2 by shaking for 3 hours.The morphology and composition of isolated chondrons were observed by HE and collagen-6 immunostaining staining after overnight coverslip monolayer culture under a microscopy.Results The chondrocytes became sparser and the total content of proteoglycans and collagen-2 were decreased in the articular cartilage with age.Compared to the chondrocytes,the surrounding rim or capsule was more obvious in the isolated chondrons,and they exhibited obvious differences in shape.The cells within one cluster from different age groups were similar to the morphology observed in cartilage in situ.The adult and old chondrons generally possessed a thicker pericellular matrix with more enclosed cells,and the chondrons contained more cells can reach 47％.Conclusion These findings further suggest that the properties of the chondrons and pericellular matrix have an important influence on the biomechanical microenvironment of the knee joint cartilage degeneration that occurs with age.

Objective To observe the effects of cyclic tensile strain (CTS) on in vitro expression of glycosaminoglycans (GAG) in rabbit chondrocytes of different ages.Methods Nine male New Zealand rabbits were grouped into juvenile (2 months), adult (8 months), and senior (31 months) groups. The bilateral knee joints were harvested using sterile technique from each rabbits. In each age group, rabbit articular chondrocytes were cultivated in vitro after randomization into a control group and a CTS group, with 6 specimens in each. In the next 3 days, CTS was applied (sin10％, 0. 5 Hz, 6 h/d) in the CTS group for 6 hours per day while no CTS was applied in the control group. After the first CTS treatment, the supernatant of cell culture was collected every 12 hours from each specimen in both groups to assess the GAG levels by Alcian blue assay.Results Expressions of GAG showed significant increases in both control and CTS groups in each age group ( P ＜ 0. 05) . Different age groups showed significant differences in the GAG secretion over different time points. Compared with the younger cells, the older ones showed the most significant difference in growth between the control and CTS groups at 12 hours, though the older cells produced less GAG than the younger ones in both groups at the end of the experiment (72 hours).Conclusions CTS can stimulate rabbit chondrocytes of different ages to secrete more GAG, and younger cells tend to produce more GAG than the older ones.

AIM: To study the inhibitive effects of valsartan and spironolactone on expression of insulin like growth factor 1 in cardiacmyocytes of spontaneously hypertensive rats. METHODS: 18 SHRs were randomly divided into 3 groups (n=6 in each): valsartan group treated with 30 mg?kg -1 ?d -1 valsartan, spironolactone group treated with 20 mg?kg -1 ?d -1 spironolactone, and control group treated with placebo. All were administrated by gastric perfusion. 6 WKY rats were served as control. After 13 weeks administration, the expressions of IGF 1 in cardiacmycytes were measured by immunohistochemistry and the IGF 1 concentrations in myocardium were measured by radiommunoassay. RESULTS: The expression of IGF 1 was higher in SHR group than that in the WKY group (P

Aim To investigate the effect of indirubin derivative PHⅡ-7 and TRAIL on proliferation in breast cancer cell MCF-7 and its MDR counterpart MCF-7/ADR and the mechanism.Methods Growth inhibition rate was examined respectively by MTT assay under treatment with TRAIL or PHⅡ-7 or in combination. Cell apoptosis and ROS production were examined by flow cytometry.The change of TRAIL receptors(DR4/DR5 )in mRNA was analysed by realtime PCR.Re-sults IC50 of PHⅡ-7 on MCF-7 and MCF-7/ADR was (4.49 ±1.55 ),(3.44 ±0.90 )μmol · L-1 respec-tively;MDA-MB-231 was TRAIL sensitive cell line, and apparently TRAIL induced apoptosis in MDA-MB-23 1 .Low concentration of PHⅡ-7 in combination with TRAIL could augment TRAIL-induced cytotoxic effect including apoptosis while TRAIL or PHⅡ-7 treatment alone had limited cytotoxity to those cells.Besides, PHⅡ-7 at this concentration had little toxicity to hu-man peripheral blood mononuclear cells even if in com-bination with TRAIL.PHⅡ-7 generated ROS produc-tion inside MCF-7 and MCF-7/ADR cells and up-regu-lated DR4/DR5 expression concentration dependently. Once upon ROS scavenger NAC involved,the effect of TRAIL receptors up-regualtion by expression was abro-gated.Conclusions PHⅡ-7 at low concentration could improve the sensitivities of breast cancer cell MCF-7 and MCF-7/ADR to TRAIL,the mechanism of which may be the ability of ROS production by PHⅡ-7 help up-regulated TRAIL receptor DR4,DR5 .Our re-search set a solid foundation for PHⅡ-7 in combination with TRAIL in future clinical application.

Objective To characterize the biomechanical behavior and properties of the chondrons enzymatically isolated from rabbit knee articular cartilage in virto. Methods Eight months old New Zealand white rabbits were randomly divided into chondroctye and chondron groups (4 rabbits in each group). In chondrocyte groups, the full articular cartilages from both knees were enzymatically isolated to chondrocytes by 0.4% pronase and 0.025% collagenase type-Ⅱ in turn. In chondron groups, chondrons were obtained from articular cartilage using the mixture of 0.3% dispase (a neutral protease) and 0.2% collagenase type-Ⅱin at 37C for 3 h. The micropipette aspiration was used to quantify changes in biomechanical properties of chondrons and chondrocytes and the viscoelastic parameters, including K1, K2, E∞ (equilibrium modulus), E0(instantaneous modulus), and μ (apparent viscosity), were calculated coupled with standard linear half-space viscoelastic solid model. Results In response to a constant negative pressure of 0.2-0.4 kPa, the chondrocytes exhibited standard linear viscoelastic solid properties. Namely, the cells showed an initial elastic response followed by a viscoelastic creep response. then cells continued to enter into the micropipette with a monotonically decreasing rate of deformation, until reaching equilibrium within about (110±18) s. Comparing with chondrocytes, the chondrons exhibited significant viscoelasticity under a greater negative pressure of 1.0-1.2 kPa. But the instantaneous length deformed into the micropipette significantly reduced, and the equilibrium time reduced to (36.5±4.5) s. The equilibrium modulus (E∞), the instantaneous modulus (E0) and the apparent viscosity (μ) of chondrons were significantly higher than the those of chondrocytes. Conclusion Comparing with chondrocytes, the chondrons exhibited significant viscoelastic properties, and viscoelastic properties of chondrons have increased in vitro.

BACKGROUND: Bone morphogenetic protein (BMP) is a protein possesses potential activity, which can increase and enhance its activity when the bone issues are damaged, so it can be used to repair the bone defects when combined with carrier. However,there are few reports concerning it as gene therapy.OBJECTIVE: To construct recombinant retroviral vector expressing human BMP2 gene and to discuss its biological function in ostecblasts.METHODS: BMP2-specific primers were designed and synthesized according gene sequence of human BMP2 gene in Genbank, then BMP2 gena was amplified by Hifi PCR, which was recombined with cloning vector pDNR-CMV homologousiy into pDNR-CMV-BMP2 plasmid identified by BMP2 PCR and enzyme digestion of Sail and EcoRI as well as gene sequencing; recombinant plasmid pDNR-CMV-BMP2 and retroviral plasmid pLP-LNCX were recombined homologously in IoxP sites into pLP-LNCX-BMP2 plasmid transferred into packing cell line PT67 and the supernatant was collected to assay viral titre. Human osteoblast was infected with retrovirus, then the growth of cells were observed by MTT, and the expression of BMP2 protein was detected by Western blotting at 48 hours transfectionRESULTS AND CONCLUSION: Digestion, BMP2 PCR and gene sequencing of pDNR-CMV-BMP2 were coincided with expected. After transfected with plasmid pLP-LNCX-BMP2, PT67 cells could be screened with G418 only to get stably integrated in BMP2, of whose supemanant viral titra amounted to 5×10~8 pfu/mL. MTT assay showed that there had no evident difference in cellular inhibition between the normal and retrovirus groups at 72 hours after transfection (P ＞ 0.05); Western blotting showed that the BMP2 was strong expressed at 48 hours after transfection. It demonstrated that BMP2 gene was successful cloned and its retrovirus vector was constructed.

BACKGROUND:Such methods as transplanting autologous periosteum or autologous bone marrow mesenchymal stem cells (BMSCs) can promote the repair of articular cartilage defects for sure. But they all have their own limits in chondrogenic abilities,which results in an unsatisfactory curative effect.OBJECTIVE:To study the effect of transplanting BMSCs (which were induced into chondrocytes) combined with autogenous periosteum on repairing articular cartilage defects in rabbits.MATERIALS:A total of 18 New Zealand rabbits,aged 6-8 months,were divided with random digits table method into 3 groups,namely,periosteum+BMSCs group,periosteum group and blank control group,with 6 ones (12 knee joint samples) in each group. METHODS:In periosteum+BMSCs group,BMSCs were harvested and adherently cultured with trypsin digestion method. Then they were induced by transforming growth factor 81 into chondrocytes. At the same time,immunofluorescence labeling was performed to BMSCs membranes with PKH-26. Full-thickness articular cartilage defects (diameter:3mm,depth:3mm) were made to bilateral condylus medialis femoris of all rabbits. In periosteum+BMSCs group and periosteum group,defects were covered by homolateral autogenous proximal tibia periosteums,with germinal layer facing to cavitas medullaris. After that,the periosteum+BMSCs group received 3 sutures,followed by injection of 20 μL BMSCs suspension (1×109/L) into the defects,after which the last suture was taken. The periosteum group underwent coverage with periosteum on defects only. The blank control group underwent perforate only.MAIN OUTCOME MEASURES:General observation,histological observation,Wakitani's score,immunohistochemical and in situ hybridization detection of collagen type Ⅱ were performed to defects at 6 and 12 weeks following operation.RESULTS:No sutured periosteums were found desquamate. In periosteum+BMSCs group,defects were filled with hyaline cartilage-like repairing tissues at week 6 following operation;Week 12 following operation saw remodeled tissues whose cells were mainly the implanted cells labeled with PKH-26. In periosteum group,repairing tissues in defect areas were ivory white,smooth with light introcession and distinctively different from the surrounding normal cartilage tissue. In the blank control group,clearer introcession or irregular appearance,even broken surrounding cartilage tissues could be seen in the defect area. Both Wakitani's score and histological score were highest in periosteum+BMSCs group at week 6 and 12 following operation (P＜0.05),with higher ones in periosteum group than in the control group (P＜0.05). What'more,matrix around cells in the repairing tissues showed positive results to both immunohistochemical and in situ hybridization staining of collagen typeⅡ,which proved that cells in repairing tissues were the implanted ones.CONCLUSION:Transplanted BMSCs (which were induced into chondrocytes) combined with autogenous periosteum can form hyaline cartilage-like repairing tissues through which articular cartilage defects are repaired.

Objective To explore the relationship among the expression level of MMP?13, AGG and Col?II in the chon?drocytes caused by nutritional deficiencies in rabbits. Methods 30 New Zealand white rabbits were randomly divided into autolo?gous chondrocyte transplantation group (control group, n=10), nutrition block group (surgery group, n=10), and peripheral nutrition block group (sham surgery group, n=10). 4 weeks after treatment, the rabbits were sacrificed for undergoing the observations on general and histological level;real?time PCR assay was employed for testing the expression level of MMP?13, AGG and Col?II;cel?lular apoptosis percentage was observed through TUNEL stain. The relationship among the apoptosis level, cartilage cells histologi?cal Mankin score as well as the expression level of MMP?13, AGG and Col?II were analyzed. Results Based on the Mankin score, there was a statistic difference between surgery group and control group. On the other side, there were no statistic differenc?es between sham surgery group and control group. 4 weeks after treatment, surgery group presented a higher apoptotic percentage compared with control group;this value between sham surgery group and control showed no significant differences. There was an increased mRNA expression level of MMP?13 and a decreased mRNA expression level of AGG and Col?II in surgery group com?pared with control group;no statistic differences of all these values was found between sham surgery group and control group. His?tological Mankin score and apoptotic percentage presented positive correlation (r=0.922, P<0.001), the regression equation:Y=-0.548+0.404X, R2=0.844 (F=157.735, P<0.001); the mRNA expression level of MMP?13 and apoptotic percentage presented positive correlation (r=0.942, P<0.001), the regression equation:Y=0.951+0.116X, R2=0.883 (F=219.054, P<0.001). There was a nega?tive correlation between the mRNA expression level of MMP?13 and the mRNA expression level of AGG as well as Col?II (r=-0.956,-0.945, P<0.001). Conclusion Damage of cartilage cells causes the up?regulation of the MMP?13 expression which could ex?acerbate the degeneration of cells. It could induce the down?regulation of AGG and Col?II mRNA expression, which will cause the extracellular matrix synthesis disorder.