Background: The aim of this study was to investigate the percentage
Background: The aim of this study was to investigate the percentage of the stem cells population in human endometrial tissue sections and cultured cells at fourth passage. Platycodin D basalis stroma (16±1.4 and 17±1.9%) respectively (P<0.05). Oct4 and Nanog-expressing cells comprise 1.43±0.08 and 0.54±0.01% of endometrial stromal cells in endometrial sections vs. 12±3.1% and 8±2.9% of cultured cells respectively. They reside near the glands in the basal layer of endometrium. Sox2 and Klf4 were not commonly expressed in tissue samples and cultured cells. CD9 and EpCAM were expressed by epithelial cells of the endometrium rather than by stroma or perivascular cells. Conclusion: The human endometrial stem cells and pluripotency markers may be localized more in basalis layer of endometrium. The immunostaining observations of endometrial cells at fourth passage were correlated with the immunohistochemistry data. Platycodin D Key Words: Endometrium Immunohistochemistry Mesenchymal stem cells INTRODUCTION Adult stem cells are rare multipotent cells that have been identified in several adult tissues such as intestine skin muscle blood nervous system and endometrium. Human endometrial stem cells were recognized for the first time by Chan et al. in 2004. Some of their properties are self-renewal high proliferative potential ability to differentiate into one or more lineages clonogenicity and tissue reconstitution in vivo[8 9 It is extremely difficult to identify these cells in tissues because they do not have certain morphological features and specific markers[10 11 During every menstrual cycle of a woman the endometrium physiologically undergoes cyclical changes such as self-renewal proliferation differentiation and shedding off [7 12 Endometrial regeneration also occurs after each endometrial incision and pregnancy[13 14 These characteristics of the endometrium have suggested the presence of a low number of endometrial-derived stem cell (EnSC) populations that seem to be responsible for its remarkable regeneration ability. EnSCs are isolated easily expand rapidly as well as produce a higher clonogenicity and a non-invasive source that make it a great therapeutic potential Platycodin D as autologous stem cell alternative in women. Phenotypically EnSCs appear to share some markers with mesenchymal stem cells (MSCs) such as CD90 and CD105. A recent study found a novel single marker CD146 that was able to isolate stem cells in human endometrium. However the localization and percentage of some stemness markers in human endometrial tissue sections and cultured endometrial cells remain unclear. Therefore further detailed studies are necessary for their identification. The Platycodin D aim of this study was to investigate the presence and the percentage of stem cells population by immune-histochemistry in human endometrial tissue sections and immunocytochemistry in human endometrial cultured cells at fourth passage. MATERIALS AND METHODS Human Platycodin D endometrial tissues Human endometrial specimens were obtained from five healthy women (aged between 30-45 years) after hysteroscopy for non-endometrial benign pathological condition. Platycodin D These women had not taken exogenous hormones for three months prior to medical procedures. The use of the human specimens was approved by the Ethics Committee of Medical Faculty of Tarbiat Modares University Tehran Iran. The normality of the endometrial tissue was proved by histological examination according to well-established histological criteria of normal menstrual cycle and confirmed by an experienced histopathologist. The proliferative stage was selected for all of the specimens in order to synchronize them. Experimental design Each endometrial specimen was divided into two parts one part for morphological and immune-histochemical studies and the other part for isolation Ly6a and cultivation of endometrial cells followed by immunocytochemical study. Morphological assessments of endometrial samples Full thickness of human normal endometrial tissues (n=5) were fixed in 10% formalin processed and embedded in paraffin wax and then sectioned at 5 μm. After routine hematoxylin and eosin staining the morphology of endometrial sections was observed under a light microscope. Other sets of paraffin sections of endometrial tissue were collected and considered for immunohistochemistry. Immunohistochemistry of human endometrial sections The paraffin sections were put on gelatin-coated slides (n=3 per each sample). After deparaffinization and rehydration with decreasing gradient.