| Objectives By increasing the occlusal vertical distance of osteoporotic rats,to explore the effect of increasing the vertical distance on TMJ synovium of osteoporotic rats,so as to provide a theoretical basis and guidance for clinical osteoporotic patients that need increase vertical distance.Methods 1 Establishing an osteoporosis model: Select 120 6-month-old adult healthy female SD rats with a weight of 200 g ± 25 g.The rats were divided into 3 groups using a completely randomized grouping method,namely the experimental group(the osteoporosis group),the sham experimental group and the normal group,with 40 rats in each group.In the osteoporosis group,80 mg/kg/d retinoic acid was administered to the stomach for 15 days,and the sham experimental group was replaced with the same amount of distilled water for 15 days.The rats in the normal group were not treated.After 15 days,each group randomly selected 5 rats to measure the body weight,and measured the femoral bone density values of the rats using a dual-energy x-ray bone density measuring instrument.2 Establishing an occlusal elevation model: After the osteoporosis model was successfully established,the rats in each group were grouped again.The rats in the osteoporosis group were randomly divided into groups A and B.The rats in the sham experimental group were randomly divided into groups C and D.The rats in the normal group were randomly divided groups E and F,20 rats in each group.The rats in groups A,C and E were raised by a resin pad to raise the vertical occlusion distance by 2 mm.The rats in groups B,D and F were not treated.3 Get experimental data: At each time point(day 7,day 14,day 21,and day 28)after the establishment of the occlusion elevation model,5 rats were randomly sacrificed in each group.The CBCT of the rat head was taken to observe the morphological changes of the temporomandibular joint,and then the synovium of the bilateral temporomandibular joint was routinely fixed in a 10% neutral formalin solution.After the fixation,HE staining was performed to observe the number of cell proliferation in lining layer,the number of capillaries in the subsynovial layer,the number of inflammatory cells,and observe the expression of IL-1? in the synovium by immunohistochemistry.4 Experimental data processing: Image-Pro Plus 6.0 software was used to measure the positive expression optical density value of IL-1?,and SPSS22.0 statistical software was used to statistically analyze bone density,body weight,HE pathological score level,and IL-1? positive expression optical density values.Results 1 During the 15 days of continuous retinoic acid gavage,the rats in the osteoporosis group gradually showed varying degrees of appetite reduction,body hair bunching,reduced activity,and slow response.Individual rats also developed arch back symptoms.Rats in the sham experimental groups and normal groups did not exhibit the above phenomenon.Using SPSS22.0 software to analyze the experimental data,the bone density of the osteoporosis group was significantly lower than that of the sham experimental groups and normal groups(P<0.05),and the difference was statistically significant.The body weight of the osteoporosis group was significantly lower than that of the rats in the sham experimental groups and normal groups(P<0.05),and the difference was statistically significant.2 CBCT results showed that on the 7th and 14 th days,the condyle surface of group A was irregular in shape.The condyle was located in the center of the joint fossa,but the joint cavity was slightly reduced.On the 21 st and 28 th days,the surface of the condyle was not smooth,and the articular cavity recovered somewhat.The recovery of the groups C and E was more obvious than that of the group A,but it did not return to normal.3 Observation under HE staining light microscope showed that the inflammation of synovium in group A was the most obvious on the 7th to 28 th days,and the inflammation gradually aggravated with the increase of time;groups C and E also showed a slight inflammatory reaction,the inflammation tends to be aggravated;inflammation in group B is mild;inflammation in groups D and F does not appear.4 The results of immunohistochemical staining showed that the positive expression of IL-1? in group A was the strongest,and strong positive expression appeared on 21 and 28 days;the positive expression of IL-1? in groups C and E was similar,which were lower than those in group A;The positive expression of IL-1? in group B was slightly lower than those in groups C and E;the positive expression of IL-1? in groups D and F was similar and weakly expressed.That is,Group A> Group C(E)> Group B> Group D(F).Conclusions 1 Increasing the vertical distance of the occlusion by 2mm caused an inflammation in the temporomandibular joint synovium of adult osteoporotic rats,and within 28 days,the inflammatory response gradually increased with time.2 IL-1? was positively expressed in the early stage of inflammation of the synovium in the osteoporotic adult rat.Elevated occlusion will have a certain impact on the temporomandibular joint of osteoporosis patients,so in the clinic,temporomandibular joint damage due to elevated occlusion should be avoided as much as possible.Figure18;Table 5;Reference 89... |
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