| The menstruation, a reproductive physiological cycle that is consisted of endometrial growth, vascular proliferation, tissue breakdown accompanied with bleeding, is unique to human primates and few other animals including the bat and elephant. Cyclic shedding of the endometrium is one of the characteristic features of the female genital system. Several teams including our laboratory established a model for menstruation in mouse via the administration of hormones or by the model of pseudopregnancy mouse since the 1980s. However, the mouse menstrual model, which is provoked through chemical or physical stimulus, is limited to reflect the real origin and progression of human menstruation as mouse does not menstruate naturally. Accordingly, it is important to establish a humanize xenograft model to facilitate the researches on molecular and cellular foundation of the menstruation. Based on the model, we further explored the mechanism of endometrial bleeding and the roles of COX in decidualization. The present study is divided into three sections as below.We set up a humanize menstruation model of through the xenograft endometrium tissue transplantation. The estrogens and progestogen were administrated after endometrium tissue was subcutaneously transplanted into SCID mouse. A comparison on morphologic and histologic changes, serum levels of E2 and progesterone, expression levels of vimentin and cytokeratin was performed between ex vivo explants and normal representatives of cycle bleeding endometrium at different time points. These results demonstrated that the menstrual-like changes in explants were similar to those of menstruating endometrium in human including cell proliferation, differentiation and disaggregation. Furthermore, some of the other features such as leukocyte infiltration, vascularization, expression levels of MMP-1,2,9, decidualization marker prolactin and COX-1,2 are likewise consistent with those of human menstruating endometrium in the present study.Based on the above founding, we further explored the roles of COX1,2 in decidualization. In our human xenograft model of menstruation, COX inhibitors including indomethacin and celecoxib could block COX activity at metabolism level. The results suggest that COX2 suppression may cause failure of the decidual reaction, but that completion of the decidual reaction once it is initiated is not limited. Indomethacin could inhibit the synthesis of PGE2 and PGF2αsimultaneously. But celecoxib can not, because COX1 can replace specific functions of COX2. Meanwhile, at molecular level, a lentivirus transfection system of human endometrium explants was established. A total of 50% infection rate was achieved by optimization of tissue culture system and transfection parameters. The technique could settle down the problem on RNAi knock down target genes in human endometrium explants, which will facilitate further studies on the underlying mechanisms of uterine diseases.Based on the improvement of isolation of primary human endometrium cells, we are establishing an immortalized human endometrium stomal cell line through liposomal transfection of hTERT. A total purity of 97% and 90% was obtained in primary human endometrium stomal and epithelial cells, respectively. RT-PCR analysis confirmed the successful and stable transfection of cells under our conditions. Two single clones of the cells treated with G418 were selected and expanded into passage 10 and 15, respectively.Taken together, we successfully established a humanize menstruation model in SCID mouse. We also revealed an important role of COX in menstruation in this model. For investigating the underlying mechanisms of decidualization, we set up a lentivirus transfection system of human endometrium explants and improved the establishment of an immortalized human endometrium stomal cell line. Above all, The model and system presented in this report will thus favor research conducted in this field. |
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