| Objective Establish an animal model of rabbit condyle osteochondral defect,analyze the effect and mechanism of Histatinl-hydrogel polymer on the extracellular matrix and osteochondral repair of cartilage defect area,and explore the application of Histatinl-hydrogel polymer in temporomandibular joint(TMJ)bone tissue engineering value.Methods 1.Six adult male New Zealand white rabbits were randomly divided into three groups,with two rabbits in each group.Defects of different sizes were made on the right condyle of the three groups of rabbits,and the left condyle remained intact.The defect diameter in the 3×3 group was 3mm and the depth was 3mm;the defect diameter in the 3 ×2 group was 3mm and the depth was 2mm;the defect diameter in the 2×3 group was 2mm and the depth was 3mm.Four weeks after the operation,the materials were taken,and HE sections were made and observed under a light microscope.2.Six adult male rabbits were randomly divided into 3 groups,2 rabbits in each group.An osteochondral defect with a diameter of 3mm and a depth of 3mm was created on the right condyle of the rabbit,and the left side remained intact.In the 50μg Hst 1/Gel-MA group,500μg Hst 1/Gel-MA group and 1000μg Hst 1/Gel-MA group 50,500,1000μg Hst 1+21μl hydrogel were implanted in the defect area respectively.Took samples 2 weeks after operation and conduct histological examination.3.54 adult male rabbits were randomly divided into 3 groups,each with 18 rabbits.An osteochondral defect with a diameter of 3mm and a depth of 3mm was created on the right condyle of the rabbit,while the left condyle remained intact.The defect area in the control group did not receive any treatment;in the Gel-MA group,Gel-MA hydrogel was implanted in the defect area;in the Hst 1/Gel-MA group,Hst 1 functionalized Gel-Ma hydrogel polymer was implanted in the defect area.Six rabbits were randomly selected from the three groups at the first 1,2,and 4 weeks after the operation,and the defect area and surrounding tissues were sampled for scanning electron microscopy,sirius red staining,and immunohistochemical detection.Results 1.After 4 weeks,HE staining showed that in the 3×3 group,only a small amount of fibrous tissue was formed at the bottom of the defect area;in the 3X2 group,a large amount of subchondral bone was observed in the defect area,and the depth of the defect area was reduced;the defect in the 2×3 group was filled with fibrous tissue.2.Two weeks after surgery,HE staining showed that there were multiple new cartilage islands in the defect area in the 500μg Hst 1/Gel-MA group.Osteoblasts and osteoclasts were observed in the new subchondral bone.The subchondral bone was over-proliferated without cartilage repair in the 1000μg Hst 1/Gel-MA group.In the 50μg Hst 1/Gel-MA group,no repaired tissue was formed in the defect.3.In the 4th week,compared with the Gel-MA group and the control group,the Hst 1/Gel-MA group showed more new chondrocytes under the electron microscope;sirius red staining showed that it was rich in type Ⅱ collagen fibers(COL II)and distributed in a loose network;immunohistochemistry showed that in the extracellular matrix,the mean IOD values of COL Ⅱ and Aggrecan(AGC)in the Hst 1/Gel-MA group were 173.16±26.03 and 61.54±11.87,which were significantly higher than the other two groups.(P<0.01).Conclusion 1.The size of the defect with a diameter of 3mm and a depth of 3mm is a suitable modeling size of the rabbit condyle osteochondral defect.2.When the ratio of Hst 1 hydrogel polymer is 500 μg Hst 1+21 μl Gel-MA,the cartilage and subchondral bone in the defect model show good signs of repair.3.Hst 1 hydrogel polymer increases the secretion of extracellular matrix COL II and AGC,thereby promoting the regeneration of condyle cartilage and subchondral bone.Clinically,Hst 1-hydrogel polymer can be used to repair joint osteochondral damage. |
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