BACKGROUND: Though there were many experiments addressing repairing osteochondral defects before, faulty restoration occurred at coupling interfaces. OBJECTIVE: To investigate the feasibility of repairing of osteochondral composite defects in rabbit knees with animal-origin osteochondral scaffold combined with bone marrow mesenchymal stem cells (BMSCs)/chondrocytes.METHODS: New Zealand white rabbits were randomly divided into the experimental, control and blank groups and prepared for unilateral knee joint osteochondral defects. Animal-origin osteochondral scaffold combined with BMSCs/chondrocytes, animal-origin osteochondral scaffold and no material was implanted to repair the defects in the experimental, control and blank groups, respectively. Healing condition was evaluated by gross observation, hematoxylin-eosin staining, and toluidine blue staining at 4, 8, and 12 weeks after operation. RESULTS AND CONCLUSION: At 12 weeks after operation, gross observation showed the defects were repaired completely without local depression and the regenerated tissues were fused with surrounding tissues in the experimental group. Hematoxylin-eosin staining and toluidine blue staining revealed that there were many new hyaline cartilages in the cartilage defects in which columnar cells were lined well and cartilage lacuna was obviously, also, there were many bony tissues in the bone defects. The regeneration cartilage, the underlying subchondral bone and host bone were coupled completely. The toluidine blue positive rate and histologic scores of the experimental group were superior to those of the control and blank groups (P < 0.05). It is demonstrated that animal-origin osteochondral scaffold combined with BMSCs/chondrocytes is an ideal method to repair defects between cartilage and the underlying subchondral bone.

Objective A comparison of two method of establishing pressure ulcer rat models to determine which is the most suitable for experimental use.Methods 18 male SD rats were randomly divided into control(n=6),model A(n=6)and model B(n=6)groups.In the control group,iodophor treatment was given after hair removal at the simulated modeling site.In model group A,longitudinal compression was performed by simple deep-tissue foreign body implantation.In model group B,transverse compression was performed via the magnet compression method.The times required to complete the process and for each stage of pressure ulcer model establishment in each group were recorded.The general condition of the rats was observed,and the modeling rate,mortality rate,and infection rate were compared.Results By naked eye,we observed that the model A and model B groups gradually developed redness and swelling,ulceration,bleeding,exudation,and necrosis.Comparison of the whole time to produce pressure uler between model A and model B groups:the difference between the two groups was statitically significant(P＜0.05).Comparison of the time to produce pressure injury between Model A and Model B:The difference between the two groups at stage Ⅰ was not statistically significant(P＞0.05);the difference between the two groups at stage Ⅱ was statistically significant(P＜0 05);the difference between the two groups at stage Ⅲ was statistically significant(P＜0 05);the difference between the two groups at stage Ⅳ was statistically significant(P＜0 05).The mental and sports scores of the rats in the control group were significantly different from those in the model A and model B groups(P＜0.05).The general state of rats in the model group A was significantly different from that in the model B group,and coat color was dimer and activity decreased in the model group A.The modelling rate of rats in both model A and model B groups was 100％.The mortality and infection rates of the model group A were higher than those of the model group B,which were 33.34％and 16.70％,respectively.Conclusions Successful preparation of a four-stage model of pressure ulers in both modalities.The two method have both commonalities and distinct characteristics.The magnet compression method required less time,the rats were generally in good condition,and the mortality and infection rates were low;thus it is suitable for short-term intervention research.The simple deep-tissue foreign body implantation method took longer,required rats to have a certain level of tolerance,had high infection and mortality rates,and is more suitable for use for long-term observations of pressure ulcers.