Regulation of angiotensin II receptors levels during rat induced pulpitis.

摘要

A change in the microcirculatory hemodynamic is one of the most important events in inflammation. In the dental pulp, which is a connective tissue surrounded by a mineralized dentine substrate, disturbance in the blood flow as well as plasma extravasation may increase the pulp pressure and cause local ischemia. The octapeptide angiotensin II (AngII) regulates vascular tone and stimulates the release of pro-inflammatory cytokines by acting through the AT(1) and AT(2) receptors. The AT(1) receptor is responsible for the classical effects of AngII. The AT(2) receptor is involved in other effects, such as vasodilation. Therefore, we aimed to evaluate the role of AT(1) and AT(2) receptors on the pulpal inflammation. The pulp tissue was mechanically exposed and after different periods the teeth were extracted and submitted to histopathological and RT-PCR analyses. The histological sections showed a number of congested and dilated blood vessels associated with a notable presence of inflammatory cells. RT-PCR data revealed that the AT(1) receptor was down-regulated at 24 h after the pulp exposure. The AT(2) receptor expression was up-regulated by a 9-hour period, and then decreased between 12- and 24-hour periods. It was demonstrated that the renin-angiotensin system plays an important role in the pulpal inflammation, with regulation of AngII receptor levels.