| Objectives To investigate the effects of unilateral type II traction on the temporomandibular joint disc and synovium in osteoporotic rats,and to provide theoretical basis and guidance for clinical patients with osteoporosis to carry out type II traction.Methods 1 127 healthy female SD rats aged 6 months were selected,weighing 200 g(+25 g).84 rats were randomly selected for bilateral ovariectomy.Eighteen of them were randomly selected for detection.Eighteen of the remaining 43 rats were randomly selected as the control group,and only the same amount of adipose tissue around ovary was removed.The total number of rats in the two groups was measured before operation,4 weeks after operation,8 weeks after operation and 12 weeks after operation.Body bone mineral density(BMD)and body mass were measured at 4 weeks,8 weeks and 12 weeks after operation to establish an animal model of osteoporosis.2 Seventy-five rats were divided into three groups: A,B and C,with 25 rats in each group.Group A was treated with NiTi springs 120 g,Group B was treated with NiTi springs 40 g,and Group C was treated with osteoporosis blank.Another 25 normal rats were selected as group D(normal group).Then each group was divided into 5 groups according to 1 day,3 days,7 days,14 days and 14 days after demolition,with 5 rats in each group.Group A and group B were divided into groups to establish unilateral type II traction models with different force values.Each group was killed according to the time(1,3,7,14,28 days).The joint discs and synovial tissues on the traction side were taken for examination.After fixation,the position and morphology of the joint discs were observed by CBCT and scanning electron microscopy.The synovial tissues were stained by HE and ADAMTS-4 and ADAMTS-5 immunohistochemical staining.The positive expression optical density(MOD)of ADAMTS-4 and ADAMTS-5 was measured by Image-Pro Plus 6.0 software.SPSS 20.0 statistical software was used for statistical analysis of data.Results 1 Gross observation of the animals after operation showed that the water intake of rats in osteoporosis group increased significantly about 3 weeks after operation,and the amount of quiet activity decreased compared with that in sham-operated group.The measurement results of BMD and body mass of rats showed that there was no significant difference between sham-operated group and osteoporosis group before operation and at 4 weeks,P > 0.05;at 8 weeks and 12 weeks,there was no significant difference between sham-operated group and osteoporosis group.There was significant difference between osteoporosis group and sham-operated group at 4,8 and 12 weeks(P < 0.05),and the results of serum estradiol(E2)measurement showed that there was significant difference between osteoporosis group and sham-operated group(P < 0.05),and all of them were osteoporosis group < sham-operated group.2 CBCT observation showed that the condyle of group A was still in the middle of the articular cavity at the top of the condyle at 7 days,and the condyle position changed at 14 days.The condyle shape of group B remained unchanged.The articular cavity was larger than that of the normal group.At 14 days after removal,the condyle of group A returned to its original position.In group B,the condyle was located in the middle of the articular cavity,and the articular cavity shrank.Scanning electron microscopy showed that the arrangement of the fibers in group A was rough and disordered on the 3rd day,with scattered fibers peeling off,and deep destruction and repair signs on the 7th day.At the 14 th day after the removal of the condyle,the shape of the condyle was normal and the position of the condyle was in the middle of the articular cavity.In group B,superficial fibrous bundles were peeled off at 7 days,and the surface of disc was still rough and not smooth and superficial free flocs disappeared at 14 days after removal.The results of case classification by HE staining showed that the inflammation of synovial membrane of temporomandibular joint in group A was aggravating gradually between 1 and 14 days,and the inflammation of synovial membrane of temporomandibular joint in group A was aggravating gradually.At 14 days after the removal of the traction device,the inflammation level was almost the same as that at 14 days,and did not subside significantly.In group B,the inflammation of TMJ synovium almost completely disappeared 14 days after the removal of traction device,and the inflammation could reach the state without traction.Immunohistochemical staining showed that there was no significant difference between groups C and D on 1,3,7,14 and 14 days after the removal of traction device,P>0.05.With the passage of time,the expression of ADAMTS-4 and ADAMTS-5 in synovium gradually increased.The expression of ADAMTS-4 and ADAMTS-5 in synovial tissue of group A and B was the highest at 14 days after removal,but the expression of ADAMTS-4 and ADAMTS-5 in group A was not significantly decreased at 14 days after removal,while the expression of ADAMTS-4 and ADAMTS-5 in group B was significantly decreased,which was similar to that in group C.Conclusions 1 Unilateral type II traction with light force and gravity can cause certain pathological changes in the temporomandibular joint disc and synovium of osteoporotic rats.2 Excessive unilateral type II traction may cause irreversible damage to the temporomandibular joint disc and synovium in osteoporotic rats.3 The pathological changes of temporomandibular joint disc and synovium in osteoporotic rats induced by unilateral type II traction are reversible.ADAMTS-4 and ADAMTS-5 can be detected in early inflammation of temporomandibular joint disc and synovium in osteoporotic rats.Figure 35,Table 7,Reference,95... |
PDF Full Text Request