| Background:The middle ear cholesteatoma is a common disease ofOtolaryngology and characterized by hyperproliferative keratinatedsquamous epithelium in the middle ear cavity. Cholesteatomaepithelium cells are not only hyperprolifetative but also overapop-tosis. In molecular biology, the domestic and international resear-chers have worked hard to study the mechanism of cholesteatomarecently. Experiment had confirmed β-catenin participated betweencells adhesive attraction. It's a improtent moity of Wnt. These affectsare relefted to tumorous proceed and development. MMP-2 educedvery important effection in many physiold and pathology course bydestructed ECM, stimulated epithelial hyperplasia, degraded bonecollagen.Objective:Study the expression and correlation of β-catenin and MMP-2in middle ear cholesteatoma and discuse their effect in choles-teatoma.Methods:20 samples of middle ear cholesteatoma we studied came fromthe patients who were operated in our hospital during Mach. 2004 toMay. 2005, and all of them had been verified to be cholesteatoma bypathology. 10 samples were normal skin of the external ear canalacquired from tympanoplasty at the same time. The wax specimenswere sliced into 4μm sections continuously. We used the immumo-histochemical technology with streptavidin-peroxidase TM. Theprimary antibodies were mouse anti-human β-catenin and MMP-2,and they were both instant antibodies. PBS was used for negativecontrol instead of the primary antibody. The main steps of operation:After deparaffinization and washing, we used saline sodium citratesolution for antigen reparetion. Edogenous peroxidase of the sectionswere inhibited with a methanolic solution and then blocked withnormal barbary serum to reduce background. Hence we fixedprimary antibody(4℃,vernight), postfixed IgG labeled by biotin,andcolor development was performed with DAB, The sectionsafterstained and occluded by neutral balsam. Under microscopicobservation at magnification ×400, we selected five random visualfields and calculated the positive cells, then with the formulaLI=∑n/∑N×100% we get labeling index(LI). We dealed with thedata with SPESS system software,used x2 test and the paired samplesSpearman-test to compare the means of paired variables with a levelof significance of p<0.05.Results:①The result showed that the positive expression β-catenin onlycould be detected in middle ear cholesteatoma ,was located at karyon,taking on yellow-brown pellet;MMP-2 could be detected inmiddle ear cholesteatoma and in normal ear cananl shin, in normalear cananl shin was located at basal layer,spinous layer cellendochylema, in middle ear cholesteatoma was located at each layercell endochylema, and basal layer colored strongest, taking onyellow-brown pellet. ②15 cases of β-catenin had positive cells in 20cholesteatoma samples, positive rate was 75%, and its LI was30.6%±13.3%;There almost no positive cells in normal ear canalskin. Compared with normal ear canal skin, the expression ofβ-catenin increased in middle ear cholesteatoma epithelium(P<0.05)③MMP-2 positive rate was 85% in 20 middle cholesteatomasamples, whose intensity was high to weak, and 50% in normal earcanal skin. The positive cells mostly in basal layer,spinous layer cellendochylema, light-brown, and its LI was 17.7%±9.5%;In middleear cholsteatoma epithelium, positive cells scattered among all layersof the epithelium, and stained strongest in basal layer, high intensive,strong-brown, and its LI was 40.1%±13.5%. They had obviousdifference(P<0.05).④In cholesteatoma epithelium samples, β-catenin-LI was 30.6%±13.3%, and MMP-2-LI was 40.1%±13.5%.They didn't have significant difference by statistics. But incholesteatomatous tissues they were correlated closely by Spearmantest.Conclusion:①The result showed the positive expression of β-catenin andMMP-2 increase in middle ear cholesteatoma epithelium, whichconfirmed that β-catenin and MMP-2 affect in middle earcholesteatoma. ②As the same time,β-catenin and MMP-2 can takeon effect relatively in middle ear cholesteatoma.
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