Effect Of Occlusal Vertical Rising On Expression Of TGF-β1, BFGF,PDGA-a, PCNA Of Condylar Cartilage In Adolescent Rats

Objective:To discuss the reconstruction process of adolescent rat’s condylar cartilage tissue, which is caused by occlusion vertical rising through building up animal models, to know the histological reaction of condylar cartilage and find out the targeting expression changes of TGF-β1, bFGF, PDGF-a, and PCNA in the cartilage cells, providing the basis for better clinical application of functional appliance.Method:To choose40male rats of5weeks and split them into the experimental group and the control group at random, with20rats for each group. For rats in the experimental group, bond light-cured composition resion plate with orthodontic adhesive to maxillary molars on both sides simulating functional appliance, to increase the rat’s occlusion (the rats are in their growth period, including the first, second and third molars). Under the same circumstances, rats in the control group are fed with no models. Then to kill5rats respectively7,14,21and28days after the occlusion vertical rising in each group and take the left condylar. After decalcification, observe the histological changes through HE dyeing method, and analyze them with computer-aided imaging analysis system. To examine the expression changes of TGF-β1, bFGF, PDGF-a, and PCNA in the rat’s condylar cartilage through SABC, and analyze the changes to discuss the impact of occlusion vertical rising on temporomandibular joint reconstruction. Result:1.HE dyeing results:1.1For the experimental group, from day7to28, there were no significant changes in the front and middle parts with the increase of condylar cells. But there were obvious changes in the rear part. On7th day, the number of condylar cells decreased, especially in the proliferation zone and hypertrophy zone. On14th day, the number of cells and thickness of the proliferation zone and hypertrophy zone gradually increased, compared with the7th day. On21st day, the number of cells and thickness of the proliferation zone and hypertrophy zone significantly increased. On28th day, no changes in the front and middle parts, but in the rear part with no pathological changes.1.2For the control group, the surface of condylar cartilage was complete and smooth, with clear structure and good continuity. There were joint surface zone, proliferation zone, hypertrophy zone, and calcified cartilage zone with distinct divides.2.According to IHC dyeing qualitative analysis, positive cells were mainly located in the proliferation zone and hypertrophy zone.2.1For the experimental group, the average optical density was the lowest on7th day, and gradually increased on14th and21st day, reaching its peak on28th day; bFGF was very high on14th day, then relatively slowly increased on21st and28th day. PDGF-a and PCNA gradually increased from7th day to28th.2.2For the control group, on7th day, positive cells with weak positive expression in the proliferation zone and hypertrophy zone were mainly located in cytoplasm nearing the cell membrane. On14th and21st day, cartilage cells experienced obvious increase and average distribution in the proliferation zone and hypertrophy zone. On28th day, the number of positive cells dramatically decreased, just a few being seen in shallow hypertrophy zone.Conclusion:1.Occlusion vertical rising can lead to condylar cartilage reconstruction, moving the condylar forward and downward and thickening the condylar cartilage tissue. New bones are formed in the process with no remarkable changes.2. TGF-β1, bFGF, PDGF-a, and PCNA are involved in adjustment of condylar cartilage tissue reconstruction process, with the balance of expression being crucial to maintain the physical health and normal reconstruction of condylar cartilage tissue.3. TGF-β1, bFGF, PDGF-a, and PCNA, with different expressions, mutually adjust and influence in the reconstruction process.