Effect of lesion location on endometriotic adhesion and angiogenesis in SCID mice

OBJECTIVE: To evaluate the effects of lesion location on adhesion and angiogenesis of transplanted endometriotic lesions in SCID mice. METHODS: Three groups of female SCID mice included intraperitoneal (i.p.) (n = 12), subcutaneous (s.c.) (n = 12), and mock surgery (control) (n = 12). At 2 weeks after ovariectomy, the mice were transplanted with eutopic endometrium from endometriosis patients either subcutaneously or sutured within the peritoneal, or underwent mock surgery. After 4 weeks, the mice were sacrificed to evaluate the adhesion and volume changes of the implanted lesions. Furthermore, semiquantitative immunohistochemical staining was performed to analyze expression of MMP-2 and TIMP-2 as adhesion makers, and vWF, VEGF, and HIF-1α as angiogenesis markers. RESULTS: Adhesion occurred in 9 of 12 mice in the i.p. group, 3 of 12 mice in the s.c. group, and 3 of 12 mice in the control group. Fisher's exact test showed that the difference of adhesion occurrence between i.p. and s.c. groups was statistically significant (p < 0.05). Graft volume changes were higher in the s.c. group than those in the i.p. group. MMP-2 expression was higher in the s.c. group than that in the i.p. group (p < 0.01). There was no significant difference of TIMP-2 expression between s.c. and i.p. groups. vWF, VEGF, and HIF-1α expression was significantly higher in the s.c. group than that in the i.p. group (p < 0.01). CONCLUSIONS: Lesion location might be involved in the pathological changes of endometriosis. The intraperitoneal location is related to endometriotic adhesion, whereas the subcutaneous location is related to the infiltration of endometriotic lesions.