| Objective:Establishing axial tooth movement model of diabetic mice to study the expression of secreted protein acidic and rich in cysteine(SPARC)and collagen Ⅰ on the periodontal tissues during axial tooth movement,to explore the mechanism of axial tooth movement and the effect of DM in order to provide fundamental basis for dentition defection in clinical treatment.Method:Sixty male C57BL/6J mice,8 weeks old with 19g-25 g in weight were used in this study.The animals were randomly divided into two groups with 30 mice each,the control group(normal)and the experiment group(DM),and each group than were randomly divided into five sub-group which is 0,3,6,9,12 days group,consisted of 6 mice each.Thirty mice were rendered diabetes by an continuously intraabdominal inject of 1% streptozotocin with 70mg/kg for five days,the remaining 30 mice were only injected citrate buffer with the same dose to served as the control group.After 72 h,blood pressure was measured every week by cutting trail and weight was measured at the same time.Four weeks later we began the research when the fasting blood-glucose value reached 11.1mmol/L or than which means model was successfully established.The three molar(M1,M2,M3)of all the mice on the right maxillary was extracted under anesthesia with 3% chloral hydrate and than hemostasis by compression.The animals were respectively sacrificed after 0,3,6,9 and 12 days and the mandibular was extracted at the same time.The specimens are fixed in 4% paraform for 24 to 48 hours,than decalcified with 10% EDTA for 40 to 50 days,conventional dehydration,paraffin,embedding,slice,HE staining to observe changes in the periodontal tissues following axial tooth movement.By the way of immunohistochemical staining,the expression of SPARC and collagenⅠand the differences in control group and experimental group were observed.Immunohistochemical image analysis system was applied to analyze the results,measure the expression area and calculate the average grey value and average optical density(OD).SPSS 19.0 statistical method was used for data processing.Result:Morphology: there was a super eruption on the unopposed molars after 12 day under the measurement of X-ray,and experimental group showed less elongation than the control group(P<0.05);Weight change: the weight of mice in two group began to descend from 3 day to 6 day(P<0.05),and more weight loss in experimental group than control group.The weight gradually rose from 9 day to 12 day in which experimental group showed slower speed than control group(P<0.05).HE staining: 1.Periodontal ligament width: the width of PDL remained unaffected from super eruption in unopposed tooth by compared with 1/3 mid-root cut sections of two sides in both experimental and control group(P>0.05);2.The amount of osteoclast: collagen was in disordered arrangement and bone matrix was uneven dyeing in experimental group with disordered bone line and osteoporosis.The osteoclasts show growth tendency from 0 day to 12 day(P<0.05).In contrast,osteoclast showed little in control group and increased gradually from 3 day to 12 day and most in 12 day(P<0.05).Only in the 12 day the amount of osteoclast in experimental group was less than control group which the differences was statistically significant(P < 0.05),the other four group all had no statistical significance(P>0.05).Immunohistochemical expression of SPARC and collagen Ⅰ: The differences of average gray value on different time of experimental and control group both was in statistical significance(P<0.05).The average gray value declined following the time and the expression enhanced.Expected the 6day,the expression of collagenⅠin experimental group was weaker than control group which the difference was statistically significant(P < 0.05).The expression of SPARC in experimental group was stronger than control group from 0 day to 12 day which was in statistical significance(P<0.05).The OD value of SPARC and collagen Ⅰ gradually increased with the time and the difference was statistically significant(P < 0.05).OD value of collagenⅠin experimental group was lower than the control group,while OD value of SPARC was significantly higher than the control group,the difference was statistically significant(P < 0.05).Conclusion:1.There was super-eruption on unopposed teeth in both control group and experimental group after extraction of molar on maxillary and the tendency of osteoporosis in diabetic mice caused less super-eruption than the normal group.2.The expression of collagenⅠand SPARC increased in the periodontal tissues of diabetes mellitus following axial tooth movement,which supposed that it maybe closed to axial tooth movement.3.The ability of bone remodeling in diabetes mellitus was weaken,activity of osteoclast were restricted in the axial tooth movement,metabolism ability of collagenⅠdecreased. |
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