PURPOSE: Platelet-derived growth factor (PDGF) has been implicated as one of the many carcinogenic factors involved in the genesis of the tumor mesothelioma. The mechanism by which PDGF participates in the pathogenesis of the pleural inflammation due to asbestos is currently unclear. The aim of this study was to compare the expression of the receptor α (Rα) PDGF in samples of pleural tissue in genetically select mice exposed to different asbestos fibers.
METHODS: Groups of 15 mice genetically selected for high or low inflammatory response (respectively, AIR max and AIR min) received intrapleurally PBS, wollastonite or 3μg/cm2 of the asbestos fibers crysotile or crocidolite. C57/Bl6 mice were used as controls. After 4, 24 or 48 hours the animals were killed and tissue samples of visceral pleura were collected and processed by immunohistochemistry for Rα PDGF. The quantification of Rα PDGF was accomplished by microscope image analysis per area of the pleura (μm2). Statistics: ANOVA.
RESULTS: Rα PDGF expression was significantly higher after 24 and 48 hours in comparison to 4 hours (p <0.001). Although not significant, the crocidolite group was higher than the crysotile group. No difference was noticed in groups control (C57/Bl6), AIR max and AIR min.
CONCLUSION: Asbestos crocidolite and crysotile produced a high Rα PDGF pleural expression shortly after 24 hours of intrapleural injection. This response was not related to the ability in producing a high or low systemic inflammatory response.
CLINICAL IMPLICATIONS: PDGF may contribute to the modulation of the acute inflammatory process due to asbestos fibers. Future studies using Rα PDGF inhibitors may shed light in the pathogenesis of asbestos injury and the genesis of the tumor mesothelioma.
DISCLOSURE: Milena Acencio, None.