Expression of macrophage inflammatory protein‐1α (MIP‐1α) in human endometrium throughout the menstrual cycle

OBJECTIVE: To investigate the distribution and the role of macrophage inflammatory protein-1alpha (MIP-1alpha) in human endometrium during cyclic changes. SETTING: Department of Obstetrics and Gynaecology, Shiga University of Medical Science and University Hospital. MATERIALS: Eighteen endometrial tissue specimens surgically resected or biopsied from women with normal menstrual cycles, without hormonal disorder or endometrial diseases. METHODS: By immunohistochemistry, using monoclonal antibodies (lambda delta 78 for MIP-1alpha and CR3/43 for human leukocyte antigen-DR (HLA-DR)). RESULTS: Immunoreactivity for anti-MIP-1alpha was distributed diffusely in epithelial cells throughout the proliferative and secretory phases but was absent during menstruation due to degenerative or necrotic changes. HLA-DR was expressed in epithelial cells only in the late secretory phase and was not expressed in stromal cells. CONCLUSION: Immunohistochemical analysis showed the presence of MIP-1alpha in the endometrial epithelium. Expression of HLA-DR in epithelial cells was observed only in the late secretory phase, suggesting that accumulation of MIP-1alpha in epithelium occurred by self production and not via a receptor mediated pathway. MIP-1alpha was released from the denuded epithelium during menstruation and appeared to contribute to the accumulation of monocytes/macrophages into the endometrial cavity. MIP-1alpha has a number of biological effects other than monocytic chemotaxis, and some of these effects may be exerted in the endometrial tissue.