The Expression Of HIF-1 A In Endometriosis And The Relationship With Angiogenesis

Hypoxia-inducible factor-1 alpha (HIF-1α) is a key controling factor whichleading the cell-mediated response to adaptation of the hypoxicmicro-environment. It was confirmed over-expression in a variety of malignanttumors and precancerous lesions and it was considered a core promoterelements of the angiogenesis. It plays an important role in the tumor invasionand the process of angiogenesis. Vascular endothelial growth factor (VEGF) is akind of specific mitogen in endothelial cell and a intensive stimulating factor inthe angiogenesis. It was known as the most stimulating factor ofangiogenesis.The research founded that VEGF was the key factor of inducingtumor angiogenesis, it have directly and specifically effect on vascularendothelial cell ,and can induce the neovascularization.The expression ofVEGF is influenced by many factors, and hypoxia is the strongest factor whichinduced VEGF expression. Eendometriosis(EM) is a kind of benign disease buthaving the tumor biology characteristic of distant metastasis and invasive ability.Angiogenesis not only play a part in the growth of the endometrial repair, butalso occupy an important position in the generation and development ofendometriosis. The research indicated that the formation of neovascularizationmay be a key to inducing the plant and growth of the ectopic endometrium,thereby inducing the generation of endometriosis.Objective: This article uses the immunohistochemical method to examine the expression of HIF-1α, VEGF and CD34 marked microvessel density(MVD)inthe normal, ectopic and eutopic endometrium of EM, to explore the relationshipbetween HIF-1αand angiogenesis and the role of HIF-1αin the pathogenesisof EM.Methods:Study Group :We collected 68 cases of ectopic endometrial tissue (EM)from the South Pearl River Medical University Hospital's gynecology andobstetrics department during the period of May 2003 to May 2006.We classifiedthe patients in stages by using the revised American Fertility Society (r-AFS): 35cases in stageⅠ-Ⅱand 33 cases in stageⅢ-Ⅳ.The patients all have a surgerybecause of EM. Under the microscope we can obviously see low fibrosis,thegland and the stroma.There are 35 patients in proliferative phase and 33 patientsin secretory phase.20 cases of eutopic endometrial tissue comes fromhysterectomy patients simultaneously from above, and 11 cases in proliferativephase and 9 cases in secretory phase.Control group: We collected 20 cases of normal endometrial tissue from thepatients who had neither endometriosis nor endometrial disease (such as uterinefibroids or uterine septum) in the same period, they underwent totalhysterectomy or diagnostic curettage and were diagnosed as normalendometrium by pathology.There are 10 cases in proliferative phase and 10 casesin secretory phase.All specimens were on the hematoxylin-Yihong (HE) staining and pathology.According to the end of menstruation and endometrial pathological examinationwe divided the menstrual cycle.There is no significant difference in age,weightand the staging of endometrial tissue between the study group and the controlgroup.The patients of the two group have regular menstruation without medicalcomplications and autoimmune disease, they have no drugs of hormones and nouse of IUD during the last six months. We used the method of Immunohistochemical staining proteinstreptavidin-biotin-peroxidase(SP) to detect the expression of protein HIF-la inthe study group and control group, in the same time we detected the expressionof protein VEGF and MVD in those endometrial tissue. We used statisticalpackage for social science(SPSS)13.0 for analysis ,all results were statisticallysignificant for 0.05. The result of MVD signed with mean±standard deviation((?)±s) .We Used one-way ANOVA, t-test, non-parametric test methods.Correlation analysis was used Spearman rank correlation analysis.Results:1. the expression of HIF-la: HIF-1αmainly localized in glandular cells ofectopic endometrium,several expressed in the stromal of ectopic endometrial.Therate of positive expression in the normal endometrium, eutopic endometrium andectopic endometrium are 0%(no patient),20% (4 of 20 patients) and 91.18% (62of 68 patients). The difference of the HIF-1αexpression in each group wasstatistically significant by statistical analyzing (x~2=63.843,P=0.000). In theectopic endometrium of endometriosis, the expression of HIF-1αhave nosignificant difference between the proliferative phase and the secretory phase (Z=-0.663, P=0.507); the expression of HIF-1αhas no significant differencebetween the proliferative phase and the secretory phase in the eutopicendometrium(Z=-0.219, P=0.827). We compared with the ectopicendometrium group and the control group to find that the expression of HIF-1αin the ectopic endometrium of EM was significantly higher than the normalendometrium(Z=-9.637, P=-0.000); the expression of HIF-1αin the ectopicendometrium of EM was significantly higher than the eutopic endometrium(Z=-7.592, P=-0.000); the expression of HIF-1αin the eutopic endometrium washigher than and normal endometrium(Z=-3.593, P=0.000). The expression ofHIF-1αhas no significant difference between theⅠ-Ⅱphase and theⅢ-Ⅳphase(Z=-0.570,P=0.569). 2. the expression of VEGF: VEGF mainly localized in the cytoplasm ofepithelial cells. The rate of positive expression in the ectopic endometrium ofendometriosis is 64.7% (44/68),in the eutopic endometrium of endometriosis is15%(3/20) and in the normal endometrium is 5%(1/20). The expression ofVEGF in each group was significantly different by statistical analyzing (x~2=27.318, P=0.000). In the ectopic endometrium of endometriosis, the expressionof VEGF has no significant difference between the proliferative phase and thesecretory phase (Z=-0.748,P=0.455); there was no significant differencebetween the proliferative phase and the secretory phase in the eutopicendometrium(Z=-0.283,P=0.777); there was no significant differencebetween the proliferative phase and the secretory phase in the normalendometrium(Z=-1.000, P=0.317) .The expression of ectopic endometrium ofEM was significantly higher than the normal endometrium as we compared withthe ectopic endometrium group and the control group(Z=-4.660, P=0.000);the expression of ectopic endometrium of EM was significantly higher than theeutopic endometrium(Z=-3.077,P=0.002); the expression of eutopicendometrium was higher than the normal endometrium(Z=-2.088, P=0.037).There was no significant difference between theⅠ-Ⅱphase and theⅢ-Ⅳphase(Z=-0.077, P=0.939).3. the expression of MVD: There was significant difference in differentendometrium (F=1786.330, P=0.000) . There was no significant differencebetween the proliferative phase and the secretory phase (F=0.065, P=0.800).In the ectopic endometrium of endometriosis, the expression of MVD has nosignificant difference between the proliferative phase and the secretory phase(t=-1.784, P=0.079); there was no significant difference between the proliferativephase and the secretory phase in the eutopic endometrium(t=0.378, P=0.703);there was no significant difference between the proliferative phase and thesecretory phase in the normal endometrium(t=0.135, P=0.894) .The expression of MVD in each group was significantly different in the proliferative phase (F=1022.06,P=0.000) ;the expression of MVD in each group was significantlydifferent in the secretory phase (F=789.045,P=0.000) .The MVD in the ectopicendometrium of EM was significantly higher than the normal endometrium (t=51.020,P=0.000); the MVD in the ectopic endometrium of EM wassignificantly higher than the eutopic endometrium(t=42.568,P=0.000); theMVD in the eutopic endometrium was higher than and normal endometrium(t=6.190,P=0.000). There was no significant difference between theⅠ-Ⅱphase andtheⅢ-Ⅳphase(t=0.496,P=0.593).4. the expression of HIF-1α,VEGF, MVD and their relationship: MVD wassignificantly correlated with the expression of HIF-1α(r=0.777, P=0.000);MVD was significantly correlated with the expression of VEGF(r=0.639, P=0.000);HIF-1αand VEGF expression was significantly correlated (r=0.906, P=0.000).Conclusions:1. Hypoxia-inducible factor-1αis over-expressed in endometriosis proved itis closely related to endometriosis.2. There was a significant positive correlation between the expression ofHIF-1αand VEGF and MVD in endometriosis.3. HIF-1α,VEGF and MVD may have played a synergetic action in theangiogenesis of endometriosis.