| OBJECTIVE:The aim of this investigation was to observe the microvessel density(MVD), the expression levels of vascular endothelial growth factor(VEGF) and tumor necrosis factor-a(TNF-a) in ectopic endometrium of experimental rats, and the effect of Thalidomide on them. To study the anti-angiogenesis mechanisms of thalidomide in ectopic endometrium, explore the contribution of thalidomide combined with gestrinone to endometriosis angiogenesis and growth of ectopic implants and its mechanism of action, and offer more experimental evidence for clinical use of thalidomide.METHODS:Normal control group was established by randomly choose 6 rats before operation. In order to let the rats under unified estrus, the rats were given subcutaneous injection of Diethylstilbestrol 0.1 mg kg-1 the day before surgery. Endometriosis models of SD rats were established referring to Vernon's methods. After 3 weeks, the size of each implant was measured by laparotomy, and part of the ectopic endometrial tissue was obtained so as to confirm with pathology that the rat model was made successfully. Then model rats were divided randomly into 6 groups that were treated with normal saline(model control), gestrinone 0.5mg·kg-1·d-1,thalidomide 5mg·kg-1·d-1(low-dose thalidomide, LTHD), thalidomide 20mg·kg-1·d-1(middle-dose thalidomide, MTHD), thalidomide 40mg·kg-1·d-1(high-dose thalidomide, HTHD), gestrinone 0.5mg·kg-1·d-1 and thalidomide 20mg·kg-1·d-1(drug combination), respectively. All the rats were treated everyday for 28 days continuously. Four weeks later, rats were killed. Ectopic uterine tissues were measured again and evaluated morphologically and histologically. MVD was immunohistochemically determined by immunostaining for factorⅧ. The expression of VEGF and TNF-αwas detected in ectopic endbmetrium by immunohistochemical SP technique.RESULTS:1. The model of endometriosis in rats was established successfully, and there was 88.9%(40/45) transplant to develop. The endometrial implants in the rats became cystic structures that were composed of endometrium, endometrial gland and stroma. The macroscopic and histological appearance were consistent with endometriosis.2. No significant difference was found in the volumes of grafts between model control group and each therapy group on the second operation(P>0.05).Treated for 4 weeks, the volume of each therapy group on the third operation was differently reduced compared with the second operation (P<0.05),and was significantly reduced compared with the model control group on the third operation (P<0.05).The effects of thalidomide on the volumes of implants were dose-dependent. There was no difference between drug combination and HTHD group (P>0.05), and both groups reduced than other groups.3. MVD in the ectopic lesion was higher in model group compared with that of normal endometrium(P>0.05). Compared with model control group, MVD in the ectopic lesion in each treatment group was decreased obviously (P<0.05).The MVD were reduced in gestrinone,LTHD,MTHD,combination and HTHD group in turn. There was no difference between LTHD and gestrinone (P>0.05). Furthermore, the effect of thalidomide on MVD was dose-dependent.4. Compared with normal endometrium, the expression of VEGF in the ectopic tissue in model control group was higher which was significantly deceased in each therapy group. In addition, the expression of VEGF showed most decreased in the combination group, while no difference between LTHD and gestrinone group (P>0.05). The inhibition of thalidomide on VEGF was dose-dependent.5. Samples from the model control group showed significantly higher expression levels of TNF-αcompared to samples from the normal control group(P<0.05),while the expression of TNF-αin each treatment group lower than model control group, and differences have statistical significance(P<0.05). the expression of TNF-a was attenuated in LTHD,MTHD,HTHD,gestrinone and combination group in turn. No difference was found among HTFHD,gestrinone and combination group (P>0.05).It was dose-dependent that THD suppress the expression of TNF-a.CONCLUSIONS:1. The rat model of endometriosis which reformed and conducted by autotransplantation of its own endometrium was successfully made.2. It can be deduced that angiogenesis, VEGF and TNF-a play a considerable role in pathogenesis of endometriosis.3. Thalidomide can decrease the quantity of micro-vessel and the expression levels of VEGF and TNF-a in heterotopic endometrium of endometriosis rats. It could exert an inhitory effect on the development of endometriosis in rats, possibly through suppression of neovascularization.4. Thalidomide restrained the ectopic endometriotic implants in EMs rats by means of dose-dependent.5. Thalidomide in combination with gestrinone had synergistic action on the depressant effect on the ectopic implants in EMs rats.
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