DISTRIBUTION AND FINE-STRUCTURE OF MACROPHAGES IN THE HUMAN OVARY DURING THE MENSTRUAL-CYCLE, PREGNANCY AND MENOPAUSE

We evaluated the distribution and ultrastructural characteristics of m acrophages in the ovaries of women of reproductive ages, during pregna ncy, and after menopause, by immunohistochemistry and transmission ele ctron microscopy. Macrophages appeared around the ovarian follicle wit h its development. Their organelles were poorly developed, and no vacu oles or granules were observed in the cytoplasm. Macrophages were also present in the cavity of the atretic follicle, being larger in size t han those in the developing follicle and characterized by cytoplasmic vacuoles and granules of a lysosomal nature. With the luteinization of the follicle, macrophages were seen to be distributed inside and outs ide the corpus luteum, but constituted only a minor population as comp ared with other kinds of leukocytes. The intracellular organelles were well-developed, including the lysosomal granules. In early pregnancy, the number of macrophages was noticeably increased in the corpus lute um. They were observed mainly outside the corpus luteum, and stained s trongly with hCG immunohistochemically. Macrophages were present in th e regressing corpus luteum and in the corpus albicans. Numerous lipid droplets and elongated cholesterol crystals were seen in the cytoplasm . Macrophages therefore appeared to be present throughout the ovarian cycle and may be involved in the development and atresia of the follic les and the progression and the regression of luteal tissues.