The Effects of Steroid and Steroid Receptor Blocker in Initial Polyp Formation

Park, Chan Hum; Na, Seon Kyu; Lim, Hyun Joon; Jung, Yin Gyo

Abstract

BACKGROUND AND OBJECTIVES: The epithelial rupture theory for the polyp formation has been well approved. According to Norlander et al., the polyp formation initiated by multifactorial pathophysiological events (infection/inflammation) appears to be a series of the consecutive events involving the rupture of epithelium, prolapse of lamina propria, epithelial ingrowth, microcavity formation, and finally the polyp formation. The purpose of this study is to determine the effects of steroid and steroid receptor blocker at the early stage of the polyp formation in a rabbit model.
MATERIALS AND METHODS
In 20 New Zealand white rabbits, polyps were induced by epithelial damage with ostial occlusion. The mometasone and RU 486, given by the biodegradable film (polylactic acid), were used to investigate the possible effects of steroid and steroid receptor blockers. After one and three weeks, macroscopic polyps were counted postmortem and on histological slides after serial sectioning. RESULT: The polyp formation was significantly increased in the RU 486-treated group, whereas it was reduced in the mometasone-treated group. According to the alpha-actin immunohistochemistry, neovascularization at the margin of the initial polyp in the RU 486-treated group markedly increased compared with the mometasone-treated group.
CONCLUSION
Steroid is thought to inhibit the initial polyp formation by reducing neovascularization particularly at the margin of initial polyp.