Effect Of Mechanical Force On The Expression Of MMP-1 And TIMP-1 In Gingival Crevicular Fluid Of Human

ObjectiveObserving the expression and change of matrix metalloproteinase -1(MMP-1)and tissue inhibitor of metalloproteinase-1(TIMP-1)in gingival crevicular fluid(GCF)of human before and after exerting different mechanical forces,to study the effect of different forces on the expression of them and discuss the possible effect MMP-1 and TIMP-1 play during tooth movement and the base of the amount of force exerted to the tooth in clinic.MethodsTwenty-four patients were chosen from the orthodontic department as subjects.Divided them into four groups at random,group A 0g of force(control group),group B 75g of force(light force),group C 150g of force(moderate force),and group D 300g of force(excessive force)were exerted to the canine tooth.The GCF were taken at 0 hr before exerting force and at 1 hr,2 hr,3 hr,4 hr,5 hr,6 hr respectively after the force was applied.The concentrations of MMP-1 and TIMP-1 in GCF were determined by the ELISA technique.We analyzed the data with statistical method,observed whether the data have changed before and after different mechanical forces were applied and the rule of the change.Results (1)The concentrations of MMP-1 in GCF changed in the same way in 75g group and 150g group:It raised significantly at 1 hr,2 hr,3 hr after exerting the force,reached the peak at 3 hr,declined at 4 hr,returned to the level after the force was applied at 5 hr,6 hr,but the average concentration level of MMP-1 in 75g group and control group is lower than that in 150g group,the difference is significant(p＜0.05).The concentrations of MMP-1 in control group and 300g group had no change before and after the force was applied,it didn′t have significant difference(p＞0.05).(2)The concentrations of TIMP-1 in GCF changed in the same way in 75g group and 150g group:It raised gradually at 1 hr,2 hr,3 hr after exerting the force,declined at 4 hr,stopped declining at 5 hr and 6 hr and maintained at a level higher than that before the force was applied. Compared the average concentration level of TIMP-1 in control group with that in 75g group and 150g group,it doesn′t have significant difference(p＞0.05).The concentrations of TIMP-1 in 300g group raised significantly at 1 hr,2 hr after exerting the force,stopped rising at 3 hr, continued to remain at a relatively high level at 4 hr,5 hr and 6 hr, compared it with control group,the difference is significant(p＜0.05).The concentrations of TIMP-1 in control group had no change before and after the force was applied,it didn′t have significant difference (p＞0.05). Conclusion(1)The level of MMP-1 in GCF changed after light force and moderate force were exerted,it had a time dependent manner.(2)The level of TIMP-1 in GCF raised significantly in the early period after excessive force was exerted,the level of MMP-1 had no apparent change.(3)To presume MMP-1 and TIMP-1,the two biological active factors,are both involved in the periodontium remodelling at the early stage,their normal expression may play a importance role in maintaining the health,the regular remodelling of the periodontium and the fast-moving of orthodontic tooth.