Analysis of MMP-2/-9 and TIMP-2 in inflamed human dental pulp

Pulp inflammation is associated to tissue degradation of extracellular matrix components and it may occur through the action of metalloproteinases (MMPs). The MMPs action may be inhibited by tissue inhibitor metalloproteinases (TIMPs). Objectives: The aim of this work was to analyze the gelatinolytic activity (MMP-2/-9) and TIMP-2 in healthy and inflamed human dental pulp. Zymographic analysis and ELISA assay were used. Methods: Intact human third molars (n=10) of young adults were used for the healthy and inflamed pulp groups (n=10), the samples were collected during the emergency treatment with a diagnosis of symptomatic pulpitis. Just after the collection, the samples were directly transferred to microcentrifuge tubes containing DMEM. Results: The group specificity was determined by the use of specific proteinase inhibitors: PMSF (serine proteinases) and phenantrolyne/EDTA (metalloproteinases). The data were submitted to analysis of variance (ANOVA) and to the detention of the differences between the groups, the Tukey test was used with a level of significance of 5%. We observed that: a) for the healthy pulp group, the protein with the highest gelatinolytic activity was pro-MMP-2, whereas in the inflamed pulp, the active MMP-9 showed the highest activity; b) in the inflamed pulp group, the gelatinolytic activity of MMP- 9 was significantly higher (p= 0.00081) when compared with the MMP-2; c) absence of MMP-9 gelatinolytic activity in healthy group; d) in the ELISA assay, higher absorbance values for MMP-9, MMP-2 and TIMP-2 were observed in the inflamed than in healthy pulps. Tukey test showed that the MMP-2 in inflamed pulp was significantly higher (p= 0.00) than MMP-2 in healthy pulp group. Conclusion: It can be concluded that MMP-2 has a participation in physiological pulp remodeling, whereas MMP-9 is highly expressed in pulp inflammation.

Financial Support: Fapesp Process n. 05/55691-1 and 05/60520-1