A Experimental Study On Origin Of Endometrial Cells In Adenomyosis

Objective: To explore origin of endometrial cells in adenomyosis by identifyingand localizing adult stem cells in the mouse uterus using label-retaining celltechnique.Methods:(1) Establishment of a mouse model of adenomyosis：The newly bornfemale ICR mice were divided into the model group and the control group.Tamoxifenwas given orally to model mice for4consecutive days from2to5day after birth.Themodel mice and the control mice were killed at45，55，65and75days of agerespectively，and the uteri were examined histologically through hematoxylin-esinstaining.(2) Identification and location of adult stem cells in mouse uterus：3day oldICR mice were intraperitoneally injected with BrdU (50μg BrdU/g of body weight)twice daily for3consecutive days.BrdU labeled mice were sacrificed after2，4，6and8week chase，uteri were harvested and analyzed for BrdU-labeled nuclei byimmunohistochemistry.Results:(1) Uterine adenomyosis was found in all mice dosed with tamoxifen after75days，but none of adenomyosis in the controls.（2）the presence and gradualdecrease of label-retaining cells were observed in the uterus during the lifespan of themice，after an8week chase，label-retaining cells were mainly located at theendometrial-myometrial interface and between myometrial inner layer and outer layer.Conclusion:(1) Oral tamoxifen can induce effectively mouse model ofadenomyosis.(2) The endometrial cells in adenomyosis may origin from adult stemcells in myometrium，their abnormal differentiation may be a major cause ofadenomyosis.