| Objective: To compare the difference of cartilage progenitor cells content in minced and monoblock articular cartilage of juvenile rabbits and to provide experimental basis for further study of the mechanism of stem cells in the repair of articular cartilage injury.Method: The articular cartilage was obtained from the distal femoral surface and tibial plateau surface of 30 hindquarters of 1 month old rabbits.A total of 72 knee cartilage culture models were prepared in vitro,and divided into two groups with 36 specimens in each group.Fragment group: the cartilage was treated by fragmentation(1×1×1 mm),and the fragments were planted in the gelatin sponge scaffold to establish an in vitro culture model.Monoblock group: the cartilage was cut into cartilage blocks about 6 mm,about 2 mm in diameter and placed in the gelatin sponge scaffold.first,24 specimens in each group were cultured for 0,2,and 4 weeks,8 specimens per time period.The HE staining was used to compare the growth of cells in the marginal area of cartilage tissue between the two groups,preliminary determination of cartilage healing.Then the percentage of the CD105 and CD166 positive cells were observed qualitatively by immunohistochemistry.Other 24 specimens were cultured for 0 and 2 weeks,chondrocytes were isolated and cultured from cartilage tissue and subcultured to the third generation.The proportion of CD105,CD166 and CD105/CD166 positive cells in chondrocytes was compared by flow cytometry.Experimental data were analyzed by SPSS 21.0 software to compare the differences between groups and groups.Result: HE staining showed that the cell density in the fragment group increased over time(4 weeks >2 weeks >0 weeks).The cells in the fragment group showed a tendency to migrate to the edge,and the tissue of the specimens cultured for 4 weeks had partially healed,while the monoblock group healed poorly.CD105,CD166 positive cell expression rate showed that the positive cell expression rate CD105 and CD166 of 0week specimen was lower,5.30±2.44 and 1.88±1.59 respectively.The expression rate of CD105 and CD166 positive cells in the fragment group was higher than that in the monooblock group in the same culture period,and the p<0.05,the difference was statistically significant.The positive expression of CD105 and CD166 in the fragment group showed an increasing trend over time,with p < 0.05,which showed significant difference;but in the monoblock group,the positive expression of CD105 and CD166 had no significant difference in different time periods,p>0.05.The flow cytometry showed that the rate of CD105,CD166 and CD105/CD166 positive cells in the fragment group was higher than that in the monoblock group and 0 weeks.CD105 was 30.31±7.25 vs13.41±6.02/13.63±4.90,CD166 was 2.12±0.92 vs 0.45±0.26/0.28±0.15,and CD105/CD166 was 1.23±0.38 vs 0.23±0.16/0.15±0.08,p<0.05,the difference was statistically significant.There was no significant difference in the proportion of CD105,CD166 and CD105/CD166 bilateral positive cells between the monoblock group and the 0 week specimen,p>0.05.Conclutions: After the fragmentation of articular cartilage in juvenile rabbits,the content of cartilage progenitor cells was increased,which promoted the repair of cartilage injury. |
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