[Objective]To investigate the feasibility of the dermal pluripotent stem cells in the repairing of cartilage defects.It was aimed to provide experimental basis in view of cartilage defects of expanding the repair of cartilage defects seed cells selection. [Method]Neonatal cyanotic blue rabbits were used.Dermal tissue directly isolated through mechanical method and cells through enzymatic digestion were obtained.The growth characteristics of adherent adhesion of stem cells were used to obtain high cloned cells,which were subcultured.The cell concentration of 1?106/ml was cultured with polylactic acid scaffold for one weeks,and the obtained result was implanted into full-thickness articular cartilage defects of rabbits.Thirty cyanotic blue rabbit(60 joints)for about 3~5 months were randomly divided into three groups:dermal pluripotent stem cell / scaffold polylactic acid in group A,polylactic acid scaffold in group B,controls in group C.Twenty joints for each group.The rabbits were killed by air embolization at 12 weeks,restoration organization was extracted and stained by HE and toluidine blue.According to the repairing result of cartilage defect,gross and histologic scoring was made,and analyzed by statistics.The comparison of score difference between each groups was performed statistically.[Result]Gross and histological observation demonstrated that in group A organizations had smooth surface,appeared transparent,good integration with surrounding cartilage and subchondral bone.In group B there was a tiny transparent cartilage,and the fiber cartilage repair accounted for much proportion.The surface of group C showed some defects,mainly characterized by fibrous cartilage repair.After gross and histological observations statistics score analysis was performed.Results showed that group A is the most optimal(P

Objective To study the preparation method of compound tissue-engineering scaffolds of the PLA/silk fibroin and evaluate its biological features.Methods The PLA scaffolds matrix were dipped into the silk fibroin solution,then dried,and PLA/silk fibroin scaffolds were prepared.There were two groups in the experiment,one group was PLA group,and the other one was compound scaffolds group.According to ISO-10993 standard,hematolysis test,dynamic coagulation time test,cell toxicity test,stimulation test and pyrogen test were performed in two groups,and the results were compared betwen two groups.Results In the stimulation test,the two kinds of materials had equally not aroused the obvious animal skin stimulation,it showed that the experiment was in accordance with the standard.In the pyrogen test,the two scaffolds material aroused the animal temperature rising without exception under 0.2℃ and the total number of degree was under 1.0℃,therefore there was no obvious difference between two groups.In the hematolysis test,the hemolysis rates of the two scaffolds samples were smaller than 5% equally(P=0.000),which indicated that the hemolysis of the compound scaffolds was better than that of the PLA scaffolds.In the dynamic coagulation time test,the coagulation time of the compound scaffolds(37 min) was longer than that of the PLA scaffolds(26 min).The anti-coagulation ability of the compound scaffolds was better than that of the PLA scaffdds.In the cell toxicity test,the cell growth situation of the compound scaffolds group was obviously better than that of the PLA group,and at the meantime the cell toxicity of the compound scaffolds was obviously smaller than that of the PLA scaffolds.Conclusion The material of PLA/silk fibroin compound scaffolds has the advanced biological consistent compared with the simplex scaffolds.Accordingly,the PLA/silk fibroin can be used as a scaffolds matrix to be transplanted into the body.

BACKGROUND: Posterior spinal fusion is a process of bone fusion under special anatomical and biological effects, which affects by many factors. With the development of bone tissue engineering, in vitro constructed tissue engineered bioactive periosteum provides a new approach for solving this problem. OBJECTIVE: To evaluate the effect of in vitro constructed tissue engineered bioactive periosteum in treating lumbar intertransverse process fusion in rabbits. METHODS: In vitro constructed tissue engineered bioactive periosteum was implanted into lumbar intertransverse process of 24 healthy adult New Zealand rabbits. Three different materials were implanted into 3 transverse process gaps (Left L_(4,5,6), Right L_(4,5,6) of each animal. Namely, bone marrow mesenchymal stem cells (BMSCs) combined pig small intestine submucosa (SIS) were implanted into the right L_(4,5) of rabbits in the composite scaffold group; pure SIS was implanted into the right L_(5,6) of rabbits in the pure scaffold group; and autogeneic ilium was implanted into the left L_(5,6) of rabbits in the autogeneic ilium group. All rabbits were sacrificed at 12 weeks after operation to perform gross, imaging and histological observation. RESULTS AND CONCLUSION: The gross observation showed that there had no significant difference between the composite scaffold and autogeneic ilium groups, but the difference was significant compared with the pure scaffold group. lmaging observation showed that the trabeculae was formed in lumbar intertransverse of rabbits in the composite scaffold and autogeneic ilium groups, however, no bone density could be seen in the pure scaffold group. Type I collagen and osteocalcin were strong positive expressed in the composite scaffold group, which had obvious difference to the autogeneic ilium group. No positive expression could be found in the pure scaffold group. It suggested that tissue engineered bioactive periosteum constructed by BMSCs combined with SIS is a well alternative to autogenous graft materials for spinal fusion.

Objective To investigate the effect of CDT1 gene over-expression on the apoptosis and cell cycle distribution in liver cells with a characteristic of genomic instability induced by radiation(GIR).Methods Lentivirus particles were transferred into liver cells of GIR to up-regulate the expression of CDT1 gene.The apoptosis and the cell cycle were detected by flow cytometry (FCM).The expression changes of p53,ATM,ATR,Bcl-2,and Caspase-3 genes were analyzed by real-time fluorescence quantitative PCR.Results CDT1 gene was efficiently increased by the gene transfection(t =15.56,P ＜ 0.05).In the CDT1 over-expressed cells,while the apoptosis ratio was increased (t =4.19,P ＜ 0.05),the expressions of p53 and Bcl-2 gene were decreased (t =-4.21,-2.06,P ＜ 0.05),but the expression of ATM,ATR and Caspase-3 changed with no significant difference compared with control.Conclusions Over-expression of CDT1 could regulate genomic instability through apoptosis pathway and checkpoint independent of p53.

Objective To explore the effects of HAVCR2 siRNA on apoptosis and cell cycle in the radiation-caused genomic instable liver cells.Methods RNAi was used to inhibit HAVCR2 gene transcription.Cellular apoptosis and cell cycle distribution were detected by flow cytometry (FCM).Expression of p53 gene was assayed by real time fluorescence quantitative PCR.Results HAVCR2 gene was effectively inhibited by RNAi (t =19.21,P ＜ 0.05).After siRNA transferring,cell apoptosis (t =3.65,P ＜ 0.05) and p53 gene expression (t =4.82,P ＜ 0.05) were decreased,and G2-phase arrest was induced(t =-3.41,P ＜ 0.05).Conclusion HAVCR2 siRNA can decrease the generation of apoptosis in the genomic instable liver cells and blocks the cells at G2 phase.

Objective To analyze the micronucleus levels of peripheral blood lymphocytes of medical radiation workers, and to provide a basis for radiation protection to reduce occupational hazards caused by ionizing radiation. Methods A total of 1072 medical radiation workers were selected into radiation group, and 329 healthy adults who underwent pre-employment occupational physical examination and intended to be radiation workers were selected into control group. The micronucleated lymphocyte frequency was determined by whole blood micro-culture. Results There were no significant differences in micronucleated cell frequency and micronucleus frequency between the radiation group and the control group (both P > 0.05). The detection rate of micronucleus abnormalities in the radiation group was significantly higher than that in the control group (P < 0.001). Female radiation workers had significantly higher micronucleated cell frequency, micronucleus frequency, and the detection rate of micronucleus abnormalities than male radiation workers (all P < 0.001). Between different types of work, significant differences were observed in micronucleated cell frequency and micronucleus frequency (both P < 0.05), but not in the detection rate of micronucleus abnormalities (P > 0.05). Radiation workers with different lengths of working showed significant differences in micronucleated cell frequency (P < 0.05), micronucleus frequency (P < 0.05), and the detection rate of micronucleus abnormalities (P < 0.001). Significant differences were observed in micronucleated cell frequency and micronucleus frequency between different age groups (both P < 0.05). The Spearman’s rank correlation analysis showed that micronucleated cell frequency and micronucleus frequency were positively correlated with the age of radiation workers (both P < 0.001). Conclusion The micronucleus frequency of radiation workers was related to the type and length of work, and had a positive correlation with age. Radiation protection should be enhanced for workers engaged in medical radiation for a long period, especially female workers and workers with a long length of service.

OBJECTIVE: To compare the effects of ~(56)Fe~(17+),~(12)C~(6+)ion beams and~(60)Co γ rays on chromosome aberration in human lymphoblastoid cells. METHODS: The human lymphoblastoid cells were divided into 0. 1,0. 3,0. 5,0. 7,1. 0,2. 0 Gy irradiated groups and 0. 0 Gy control group. They were separately exposed to ~(56)Fe~(17+)ion beams( linear energy transfer was 400. 0 ke V/μm),~(12)C~(6+)ion beams( linear energy transfer was 26. 0 ke V/μm) and~(60)C γ rays. Chromosome specimens were harvested 48 hours after irradiation. The effects of different radiation on dicentric plus centric ring( “d + r”) aberration rate and chromosome aberration in human lymphoblastoid cells were detected by light microscope with artificial counting. RESULTS: The “d + r”aberration rates induced by 0. 3-2. 0 Gy ~(12)C~(6+)ion beams were significantly higher than those of ~(56)Fe~(17+)ion beams and~(60)Co γ rays at the same dose( P < 0. 017). Chromosome aberration cell rates of 0. 1-2. 0 Gy ~(12)C~(6+)ion beams were significantly higher than those of ~(56)Fe~(17+)ion beams and~(60)C γ rays at the same dose( P < 0. 017). At the dose range of 0. 0-2. 0 Gy,chromosome aberration effects of three kinds of radiations were gradually increased( P < 0. 01). The relative biological effectiveness of ~(56)Fe~(17+)ion beams was lower than that of ~(12)C~(6+)ion beams.CONCLUSION: The chromosome aberration induced by ~(12)C~(6+)ion beams was more serious than that of~(60)Co γ rays and ~(56)Fe~(17+)ion beams.