ULTRASTRUCTURAL CYTOCHEMICAL STUDY OF PROTEOGLYCANS IN THE ENDOMETRIUM OF PREGNANT MICE USING CATIONIC DYES

Decidualization in rodents is accompanied by remarkable modifications of both fibrillar and non-fibrillar components of the endometrial extr acellular matrix, Biochemical studies have shown that the levels of sy nthesis of hyaluronic acid and sulfated glycosaminoglycans change duri ng decidualization in rodents. As the rodent decidua has regions conta ining cells in different stages of decidual transformation, we decided to analyse, by an ultrastructural cytochemical technique, the distrib ution of protreoglycans (PGs) in each region of the decidua of mice on different days of pregnancy. Endometria of mice on days 4, 5 and 7 of pregnancy were processed for electron microscopy in the presence of s afranin O, a cationic dye which preserves most of the tissue PGs. The endometrium of non-pregnant mice was used as control. We observed evid ent differences in the arrangement and distribution of the network of PGs between non-pregnant and 4-day pregnant endometria, as well as bet ween different regions of pregnant endometria. The possible relationsh ip between these modifications and cell transformation that occurs dur ing decidualization is discussed.