Zymography Research On The Expression Of MMP-2 And MMP-9 In Dentin Bonding By Pretreatment With MMPs Inhibitors

ObjectivesTo investigate the expression of MMP-2 and MMP-9 under the action of MMPs inhibitors after immediate bonding and aging bonding in elf-etch adhesive and etch-and-rinse adhesive,and to provide the basis for improving the binding effect of matrix metalloproteinase inhibitor.Methods:20 adult teeth were collected and ground into dentin powder under liquid nitrogen cooling;To simulate the oral condition,self-etch and etch-and-rinse were treated respectively.The dentin without any treatment was the negative control group,the dentin treated with etching was the positive control group,the dentin treated with adhesive was the blank control group;The matrix metalloproteinase inhibitor chlorhexidine and minocycline were pretreated during the bonding process,we marked it as CHX group and MI group.On the basis of the above conditions,10%sodium hypochlorite was used for dentin aging,we marked it as aging blank group,CHX aging group and MI aging group these were aging blank group and aging experimental group;Gelatin zymography was used,incubated,stained and decolored,the strip was analyzed by gel image analysis system,the relative gray value of the negative control group was 1,the gray value ratio of corresponding stripe was used as evaluation indexes.Results:Under the condition of etch-and-rinse bonding,compared with the blank control group,in the CHX group and MI group the expression levels of MMP-2 were both decreased(P<0.05).Compared with the aging blank control group,the levels of MMP-2 were decreased in the CHX aging group and MI aging group(P<0.05).Moreover,there was no statistical difference in the expression level between the CHX group and the MI group.Under the condition of self-etching bonding,compared with the blank control group,the expression levels of MMP-2 and MMP-9 in the dentin powder of CHX group were decreased(P<0.05),and the expression levels of MMP-2 and MMP-9 in the dentin powder of MI group were decreased(P<0.05).Compared with the aging blank control group,the expression levels of MMP-2 and MMP-9 in the dentin powder of CHX aging group were decreased(P<0.05),and the expression levels of MMP-2 and MMP-9 in the dentin powder of MI aging group were decreased(P<0.05).the expression level of MMP-2 in MI aging group was lower than that in CHX aging group(P<0.05).There was no significant difference in the inhibition of CHX and MI on the two forms of MMP-2 under the condition of etch-and-rinse bonding(P>0.05).Under the condition of aging self-etching bonding,the inhibitory effect of MI on MMP-2 expression level was superior to that of CHX(P<0.05).Conclusion:1.Both self-etch bonding and etch-and-rinse bonding can activate MMP-2 and MMP-9 in dentin to varying degrees,thus reducing the bonding strength.2.Matrix metalloproteinase inhibitors CHX and MI can inhibit the activity of MMP-2 and MMP-9 under the condition of immediate bond and aging bond in two kinds of bonding system,so as to improve the bond strength and bond durability.