Expression And Significance Of Streptococcus Mutans Induces MMP-8 MRNA In Human Dental Pulp Cells

Abnormal increase of MMPs In inflamed dental pulp results in unbalanced synthesis and metabolism of extracellular matrix and accelerates pathological changes to dental pulp necrosis.Matrix metalloproteinases (MMPs) are a group of endopeptidases which are dependent on divalence metal cation .Matrix metalloprote- inases(MMPs) are enzymes that digest components of the extracellular matrix(ECM). MMPs are involved in many physiological processes, such as embryonic development,bony remodeling, angiogenesis, apoptosis etc as well as arthrophlo- gosis , periodontal supernatant disease, fibrous degeneration and so on in many pathological processes. MMPs(MMP-2, MMP-3, MMP-8, MMP-9, MT1-MMP and MMP-20) in dental pulp are synthesized by pulp cells and odontoblasts MMPs participate in degradation processes of ECM in tissues absorption and many pathological changes processes, but also changing the function of ECM by specific proteolysis.Many kinds of macromolecules synthesized extracellular matrix (ECM) that was a accurate network structure , and the macromolecules contain collagen, noncollagen protein, stress protein,proteoglycan,glycosaminoglycans and so on. extracellular matrix (ECM) can provide the suitable circumstance for cells to sustain vital movement and differentiation,influence the form of cells, control migration ,regulate generation,induce differentiation. It is necessary to embryonic development and the absorption & rebuilding of morphopoiesis tissues for extracellular matrix degradation at the right time. But, abnormal increase of MMPs in inflamed tissue results in unbalanced synthesis and metabolism of extracellular matrix, and accelerates pathological change , finally cause tissue necrosis because of the lack of supplying .MMP-8,one of the important factors in body injure mechanisms, is a member of interstitial collagenases and has most powerful ability to degradatethe collogenâ… .Dental pulp has the special loose connective tissues . The collogenâ… ,â…¢are main part of composition which constitute the extracellular matrix . Recent research has discovered that MMP-8 play an important role in physiological processes of pulp.MMP-8 is generated by histiocyte, phagocyte , immature monocyte , heterophil granulocyte , keratinocyte, endotheliocyte . In pulp tissues , the dental pulp cells and odontoblasts synthesize most MMP-8 ,and the former synthesize the most. Researches have showed that the presence of MMP-8 was found to be significantly higher in inflammation and sphacelism of injured tissues.At present, the interval and oversea scholars invest more on MMP-3 in pathological changes processes: the presence of MMP-1, MMP-2, MMP-3, were found to be significantly hi-gher in inflamed pulp tissue,and MMP-1, MMP-3 were major located in heterophil granulocytes, macrophages when the ef-flusion emerged causing by acute endodontitis and in extracellular matrix, above all, we can include that there is relationship in MPPs and patients'rational symptoms in some degree.Aim: The aim of this study was on the base of infecting pulp cells (getting from cultivated human pulp cell in extraorgan ) by streptococcus mutans supernatant , to observe the expression of MMP-8 mRNA in dental pulp cells , to invest the influence of MMP-8 in pulpitis extracellular matrix degradation, and to investigate the effect of MMP-8 mRNA in pulpitis . Methodology: The experiment is divided to two stages . firstly fresh dental pulp tissue were choosen; cultivated human pulp cells with architecture method, immunohistochemistrySABC and biochemistry ; detect the character of pulp cells by observing the changes of cell growth cycle, keratin, waveshaped fibroin expression,the activity of ALP . Secondly, streptococcus mutans supernatant was used to infect pulp cells , detect the expression of MMP-8 mRNA in dental pulp cells by RT-PCR .Results: EXP1 showed that most dental pulp cells were typical collagenoblasts(astroshape , fusiform shape , chubby body , uniformly cytoplasm , prominent nucleolus.) ; the result from immunohistochemistry showed that keratin was negative, and waveshaped fibroin was masculine in pulp ; the curve of ALP activity accorded with the regularity of ALP activity in pulp cells . EXP2 showed that the MMP-8 mRNA was never found in normal pulp cells ; but in infected pulp cells by streptococcus mutans supernatant , it was found to be significantly higher.Conclusions: Based on these results, it was concluded that it is feasible to cultivated human pulp cells with architecture method ; streptococcus mutans supernatant can induce the expression of MMP-8 mRNA in pulp cells ; MMP-8 is one of the important activity factors in endodontitis directly ; we can confirm that MMP-8 plays an important role in pathogenesy of endodontitis.Above all, theoretical evidence were provided for clinical pulp preservative therapy , that was to search for effectual restrainer to prevent degradation of the extracellular matrix (ECM).