Biochemical analysis of the interaction process between MTA and PLA2

The activity of the phospholipase A2 protein (PLA2) is directly related to the inflammatory process.  The Mineral Trioxide Aggregate (MTA), used for cases of pulp exposure should perform its function without inducing an inflammatory response. The interaction of PLA2 with the MTA can lead to an activation of the process that leads to pulp necrosis. Objectives: This study aimed to analyze using chromatography and mass spectroscopy the interaction between MTA and PLA2. Methods: The calcium hydroxide was used as control tests. The MTA powder (Angelus) and calcium hydroxide were incubated for 60 minutes in the presence of PLA2 (mol: mol). 200 µl of the samples were injected into a reverse-phase HPLC and eluted with a gradient of buffer A (0.1% TFA) and buffer B (66.6% acetonitrile in buffer A). The interaction of PLA2 with the materials was determined by absorption spectra using UV detection (280 nm). The mass spectroscopy was performed from an ESI source, which was set up in positive ionization mode with the following conditions: gas flow of 500l / h at a temperature of 30°C. The capillary and cone voltages were set at 35V and 3000V, respectively, and samples were diluted in acetonitrile and formic acid. Results: The analytical techniques used were able to detect changes in PLA2. After few seconds, the chromatographic profile showed changes in the profile and retention time of the protein.  There was also a change of mass fragmentation of PLA2 treated by MTA. Conclusion: The results indicated significant interaction between the MTA and PLA2 that may be useful in understanding the mechanism of action of MTA in the development of the inflammatory process.