Bone Marrow Derived Stem Cells Differentiate In The Direction Of Endometrium In Ectopic Lesions

BackgroundEndometriosis(EMs) is one of the common benign gynecological diseases;and its major symptoms are dysmenorrhea,infertility,dyspareunia,etc.These symptoms seriously affect women's health and life quality.Several theories have been raised to address the origin of EMs,like Sampson's Theory,Metaplasia Theory and Immune Theory.But the pathogenesis of EMs still remains unclear.Several studies focus on the researches on stem cells(SCs) have proved that there are stem/progenitor cells exist in endometrium.They induced the periodic regeneration of endometrium.Concerning on the ectopic lesions may be not capable to maintain their long-time development only due to the differentiated cells,the implication of the endometrial stem cell hypothesis is that ectopic differentiation of stem cells may be a novel mechanism of the disease,that is endometriosis is a stem cell-related disease.Here,an endometriosis murine model,received bone marrow transplantation (BMT) from male GFP transgenic mice and then applied 17 beta-estradiol,was set up.If GFP positive cells can express the marker of endometrial glandular epithelial cells at ectopic endometrium,we can conclude that bone marrow stem cells of male mice can participate in the formation of endometriosis.There may be a new era of the pathogenesis and clinical research on EMs.Materials＆Methods1.Experimental Endometriosis Murine ModelBoth donors and recipients are eight-week-old wild-type female C₅₇BL/6J mice. Segments of dornor mouse uteri were transferred into the peritoneal cavity of recipient mice through intraperitoneal injection.2.Bone Marrow Transplantation(BMT)Donor bone marrow was flushed from the femurs and tibias of four-week-old GFP transgenic male C₅₇BL/6J mice.After applying different dose of radiation (0cGy/650cGy/850cGy),recipients were transplanted with unfractionated bone marrow cells by tail vein infection.3.17 beta-estradiol Supplement17 beta-estradiol oil solution(0.4mg/ml) was intramuscular injected 0.1ml/week. Oil was injected 0.1ml/week as a control.4.2-3 months later model mice were sacrificed and specimens were examined bytissue immunofluorescent staining,in vivo imagine system(IVIS) and so on.Results1.All ectopic endometrium was alive and the cake-like or punctiform ectopic endometrium was found between intestines,around uterus,under abdominal wall or under hepatic lobules or spleen in the model mice and adhering zone was also seen between intestines,between the ectopic endometrium and abdominal wall and between the ectopic endometrium and spleen.Typical endometrial gland and mesenchymal was seen under the microscope,which inferred that the mouse model was successful.2.Macroscopic appearance shows that uterine of irradiated mice were relatively atrophy,and endometriosis lesions are less and smaller.3.Observe under in vivo imagine system(IVIS),there is a GFP positive cells enrichment in the endometriosis lesions after bone marrow transplantation.More GFP positive cells are observed in the recipient mice which received 17 betaestradiol treatment.4.GFP positive cells which is Cytokeratin positive were found in the wild-type ectopic endometrium implanted in the peritoneal cavity.Conclusion:1.There is a bone marrow derived cells(BMDCs) enrichment in the endometriosis lesions after bone marrow transplantation.17 beta-estradiol may promote this process.2.Male BMDCs can achieve long-term colonization in ectopic endometrial lesions, and differentiate in the direction of glandular epithelial cells.