Study On The Expression Of AngⅡ And AT1 Receptor In Oral Submucous Fibrosis

Objective: To investigate the expression and distribution of Ang II and one of it's receptors- AT1R in Oral submucous fobrosis(OSF),and further discuss the pathological mechanism of OSF.Methods: The specific SP immunohistochemistry was used for detecting the expression and distribution of Ang II and AT1R rabbit anti-human polyclonal antibodies in 5 normal controllers and 30 cases of victims who suffered from OSF respectively. The rate of positive reaction were observed and counted blindly, and the staining intensity were judged by average gray-level.Results: (1) A slight positive expression of Ang II protein was detected in normal oral mucosa, and a significant increase of expression could be found in early stage of OSF; No constant growth but a decline was seen in the intermediate and advanced stages, however, the expression were still maintain strongly positive. A significant difference was between each stage of OSF and normal controls(P<0.05).The expression of Ang II protein in epithelium was much higher than in submucosal connective tissues with regard to any stage pathogenisis of OSF, the differences were of statistical significance(P<0.05).(2)A positive expression of AT1R protein was seen in normal oral mucosa. It was showed strong and moderate expression under the pathological circumstances of OSF. An utmost summit of AT1R protein expression was reached in early stage of OSF, and maintain a constant level yet not so high level in intermediate and advanced stages. The differences between normal control and early or intermediate stage were significant(P<0.05); No significant difference was found in the expression between the advanced stage OSF and control(P > 0.05).The AT1R protein showed a significant expression in epithelium and submucosal connective tissue no matter what stage of OSF. The density of distribution between the two tissues showed no statistical difference(P > 0.05).Conclusions: (1) The expression of Ang II and AT1R protein both have been found in normal oral mucosa, which may indicate the existence of local rennin angiotensin system ,The combination of Ang II and AT1R can maintain the physiological function of oral mucosa.(2 ) The upgrade expression of Ang II and AT1R protein in the lesion of OSF, indicate the selective binding of Ang II and AT1R may contribute to the pathogenisis of OSF.(3 ) The protein expression and distribution of Ang II in normal and OSF epithelium and submucosal connective tissue are not always accompany with AT1R, which may suggest that AT1R only attribute to the role of Ang II partially.