The Expression And Significance Of HGF,VEGF In Middle Ear Cholesteatoma

ObjectiveCholesteatoma of the middle ear is an inflammatory disease characterized by the presence of hyperproliferative keratinizing squamous epithelium in the middle ear cavity and destruction of adjacent bone. Its essential damages is the bony destruction of middle ear, causing hearing loss, intracranial or extracranial complication, resulting in death in the end . Its mechanism of erosion behavior is not completely clarified. Recent studies have proved angiogenesis may be a major factor in the erosion behavior of middle ear cholesteatoma. This study aimed to analyze the expression of Hepatocyte growth factor(HGF), Vascular endothehal growth factor(VEGF) in middle ear cholesteatoma and to investigate the relationship between the angiogenesis induced by HGF, VEGF and the erosion behavior of middle ear cholesteatoma.MethodsCholesteatoma specimens were collected at time of surgery, fixed immediately and made into paraffin section. At the same time the extent of inflammation was noted. Immunohistochemical method and the computer image quantitative analysis were used to examine the expression of HGF, VEGF and microvessel density (MVD) in 34 samples (4-5 um paraffin sections) from cholesteatoma and 15 normal cases. In addition, the correlation between the expressions of the two indexes, MVD and the the extent of inflammation were observed. The aim is to elucidate the mechanism of angiogenesis in the erosion behavior of middle ear cholesteatoma.Results1. The expression of HGF, VEGF in cholesteatoma and EACS: The positive immunostaining of HGF and VEGF appeared brown granular distribution, localized in the cytoplasm. In cholesteatoma, HGF protein was expressed both in cholesteatoma epithelium and stromal cells ;In EACS, it was only expressed in basal layer. In cholesteatoma, VEGF was expressed both in epithelium and stromal cells, In EACS, it was only expressed in basal layer.2. The results of the computer image quantitative analysis showed that the mean optical density of HGF was 0. 2618±0.04105 in cholesteatoma epithelium and stromal cells and 0.2075±0.01855 in EACS, both of which had significantly differentiation(P=0.003) ; the mean optical density of VEGF was 0.3842±0.05623 in cholesteatoma epithelium and stroma and 0.2616±0.02010 in EACS, both of which had significantly differentiation(P=0.000) ; in addition, by relation analyse we found that over-expression of VEGF is significantly associated with the expression of HGF(r=0.831 P=0.000).3. In 34 samples of cholesteatoma (I, II, III) in which HGF was expressed, Statistical analysis showed the mean optical density of HGF between them had significant difference (P=0.001), suggesting that HGF is relative to the extent of inflammation. In 34 samples of cholesteatoma(I, II, III) in which VEGF was expressed, Statistical analysis showed the mean optical density of VEGF between them had significant difference(P=0.009), suggesting that VEGF is relative to the extent of inflammation.4. Number of microvessels (collagen type IV staining) : The mean number of vessels in EACS is 5.1±1.0/W(n=15), 22.1±11.3/mm~2 (n=34)in cholesteatoma ,there was statistical significance between the two groups(P< 0.05). And the mean number of vessels increased with the degreeof inflammation within the perimatrix(Grades I -III) from 9.3±3.6 vessels/mm~2 (Grade I) to 21.1±3.4 vessels /mm~2 (Grade II)and 32. 5±9. 5 vessels/mm~2 (Grade III), Statistical analysis showed that the MVD among the threegrades had significantly differentiation(P< 0. 05)5. In 34 samples of cholesteatoma in which HGF was expressed, the mean number of vessels increased with the degree of expression from 8. 5±2.3 vessels/mm~2 (Grade I)to20.6±3. 1 vessels/mm~2 (Grade II)and 32.0+8.5 vessels / mm~2 (Grade 11I), Statistical analysis showed that the MVD between the three grades had significantly differentiation(P< 0. 05). In 34 samples of cholesteatoma in which VEGF was expressed, from 9. 4±2. 6 vessels/mm~2 (Grade I)to 22. 3±3.3vessels / mm~2 (Grade II)and 32. 5±8.5 vessels /mm~2 (Grade 11I), Statistical analysis showed that the MVD between the three grades had significantly differentiation(P＜0.05).Conclusions1. HGF and VEGF are over-expressed in cholesteatoma and they are associated with the extent of inflammation, which show that HGF and VEGF are responsible for the erosion behavior of cholesteatoma.2. The mean number of vessels is associated with the expresstion of HGF and VEGF, indicating that HGF, VEGF contribute to angiogenesis of middle ear cholesteatoma.3. The mean number of vessels increased with the degree of inflammation within the perimatrix, indicating that angiogenesis induced by HGF and VEGF is a major factor in the erosion behavior of middle ear cholesteatoma.