Análise morfológica e morfométrica da reação tecidual provocada por pastas endodônticas contendo fração acetato de etila de Pothomorphe umbellata em tecido conjuntivo subcutâneo de ratos

Abstract

Several chemical substances are used in endodontics as intracanal medication, aiming at diminishing the bacterial contingent present in teeth with pulp necrosis. In this study 4 medicinal pastes were comparatively analyzed, namely: Calcium hydroxide + propylene glycol (Group 1), ethyl acetate fraction of Pothomorphe umbellata + propylene glycol (Group 2), ethyl acetate fraction of Pothomorphe umbellata + propylene glycol + calcium hydroxide (Group 3), ethyl acetate fraction of Pothomorphe umbellata + propylene glycol + calcium hydroxide + zinc oxide (Group 4). For this purpose, 15 male rats weighing 250 g in average were distributed in accordance with the experimental periods: 7, 21 and 42 days). The pastes were administered via polyethylene tubes that were then implanted in the subcutaneous tissue of rats, in the dorsal region, being 2 scapular and 2 pelvic regions totalizing 4 tubes per animal. After the stipulated periods, the animals were sacrificed and the tissues were processed in a laboratory to obtain the histological cuts for future histopathologic analysis. The results were classified regarding severity of the inflammatory reaction and quantified with regard to the number of cells present in pre-determined areas. The results showed diminishment of inflammatory response and good tissue tolerance during the course of experimental periods. Macrophagic activity carried out by the mononuclear phagocytes and giant inflammatory cells showed to be accentuated in the initial periods decreasing in the final periods and irritant potential becoming acceptable during the course of the periods studied. Statistical analysis showed no significant statistical difference between the pastes tested in comparison with the histopathologic events assessed, but there was a significant statistical difference regarding the histopathologic events when compared with the different experimental moments. It may be concluded that the pastes with ethyl acetate fraction of Pothomorphe umbellata presented an acceptable irritant potential when used in the subcutaneous conjunctive tissue of rats.