Research About The Function Of Pgp9.5in Temporomandibular Joint Osteoarthritis Of Rats With Occlusal Trauma

Objectives:To establish TMJ OA (tempromandibular join osteoarthritis) rat models, evaluate the histological changes of condylar cartilage, and investigate the expression of PGP9.5in the nerves of joint capsules and condylar cartilage. Explore the correlation between histological changes and PGP9.5expression, and discuss the roles PGP9.5plays in TMJ OA, in order to provide a theoretical basis for the treatment of TMJ OA.Methods:A total of608-week-old female Wistar rats (provided by the Experimental Animal Center of Shandong University), weighing200-250g, were randomly divided into one control group (n=10) and five experimental groups (n=10). TMJ OA rat models were established by bonding an orthodontic square wire on the occlusal surface of the right first maxillary molar to create occlusal trauma. The TMJs were prepared for HE, immunohistochemical staining and real-time PCR analysis at1,3,7,14and28days after teeth operation. Compare the histological changes and PGP9.5expression between the experimental groups and the control group, and between the traumatic sides and the non-traumatic sides of experimental groups; analyze the correlation between histological changes and PGP9.5expression.Results:1) Histological changes of condylar cartilage:OA-like lesions were induced in the experimental group rats, with the Colombo histological scores ranging from6.32to18.35in different groups, which indicated that the TMJ OA models were established successfully. The Colombo histological scores of the experimental groups gradually rose on the1st,3rd and7th days, and reached the peak on the7th day before decreasing by the14th and28th days. The scores of experimental groups were significantly higher than those of the control group on the1st,3rd,7th and14th days (p<0.05). The scores of traumatic sides were significantly higher than those of the non-traumatic sides on the3rd,7th and14th days (p<0.05).2) PGP9.5mean OD value:The PGP9.5mean OD value of the nerves of joint capsules gradually rose on the1st,3rd and7th days, reaching the peak on the7th day, and then decreasing by the14th and28th days. The mean OD of experimental groups were significantly higher than those of the control group on the1st,3rd and7th days (p<0.05). The mean OD of traumatic sides were significantly higher than those of the non-traumatic sides on the3rd and7th days (p<0.05). The PGP9.5mean OD value of condylar cartilage gradually rose on the1st,3rd and7th days, reaching the peak on the7th day, and then decreasing by the14th and28th days. The mean OD of experimental groups were significantly higher than those of the control group on the3rd,7th and14th days (p<0.05). The mean OD of traumatic sides were significantly higher than those of the non-traumatic sides on the7th and14th days (p<0.05).3) The expression of PGP9.5mRNA:The expression of PGP9.5mRNA of the nerves of joint capsules gradually rose on the1st and3rd days, and then decreasing by the7th,14th and28th days (p<0.05). The mRNA expression of experimental groups were significantly higher than those of the control group on the1st,3rd and7th days (p<0.05). The mRNA expression of traumatic sides were significantly higher than those of the non-traumatic sides on the3rd and7th days (p<0.05). The expression of PGP9.5mRNA of condylar cartilage gradually rose on the1st and3rd days, and then decreasing by the7th,14th and28th days (p<0.05). The mRNA expression of experimental groups were significantly higher than those of the control group on the7th,14th and28th days (p<0.05). The mRNA expression of traumatic sides were significantly higher than those of the non-traumatic sides on the1st,3rd, and7th days (p<0.05).4) Correlation analysis:A positive correlation exists between PGP9.5mean OD and Colombo histological scores of condylar cartilage (r=0.817,p<0.05).Conclusions:Experimentally created traumatic occlusion can induce obvious TMJ OA-like lesions. Traumatic occlusion was found to raise the expression of PGP9.5and PGP9.5mRNA in the nerves of joint capsules and condylar cartilage. In addition, a positive correlation exists between PGP9.5expression and Colombo histological scores of condylar cartilage. Therefore, new ideas for etiological mechanism study and clinical treatment of TMJ OA were provided.