Publications (2)1.42 Total impact
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ABSTRACT: MFG-E8, a secreted integrin-binding protein, consists of two EGF domains containing a RGD motif and two discoidin domains. In mouse embryogenesis, MFG-E8 is highly expressed in gonadal stromal cells near mesonephros at 11.5-12.5 dpc, but its function in gonadogenesis has not been characterized. To clarify a possible role of MFG-E8 in developing gonads, we analyzed the adhesion activity of 10.5-15.5 dpc gonadal cells to recombinant proteins of EGF or discoidin domains of MFG-E8. In EGF-coated wells, the gonadal cells at 11.5-12.5 dpc revealed a significantly higher adhesion activity as compared to those at 10.5 and 15.5 dpc, while discoidin domains showed a constant number of the adhered cells throughout these stages. To identify the adhesive cells of 11.5-dpc gonads, immunohistochemistry with anti-SF1/Ad4Bp antibody (a specific marker for supporting, steroidogenic, and coelomic epithelial cells) and staining for alkaline phosphatase (a germ cell marker) were carried out. As a result, EGF domains, as well as discoidin domains, were capable of binding to all three groups of SF1/Ad4Bp-positive and negative somatic cells, and germ cells of 11.5-dpc gonads. These findings therefore suggest that MFG-E8 mediates the cell-to-cell interaction among several somatic cell types and germ cells in mouse early gonadogenesis.Anatomy and Embryology 08/2005; 209(6):485-94. · 1.42 Impact Factor
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ABSTRACT: The phthalate esters have been used as plasticizers for various plastic products, and their testicular toxicity has been reported. In this study, the effects of mono(2-ethylhexyl) phthalate (MEHP), one of the phthalate esters, on prepubertal rat testes in vitro were examined. The testes of 20-day-old Sprague Dawley (SD) rats were cut into smaller pieces and seeded in medium, and then the specimens were obtained for light and transmission electron microscopic observations. As a result, at 1 hr after exposure to MEHP, TUNEL-positive spermatogenic cells were identified, and they gradually increased in number in time-and dose-dependent manners. Ultrastructurally, apoptotic spermatogenic cells (characterized with chromatin condensation, cytoplasm shrinkage without membrane rupture, still-functioning cell organelles, and packed cell contents in membrane-bounded bodies), necrotic spermatogenic cells (characterized with swollen and ruptured mitochondria, plasma membrane lysis, spilt cell contents, and chromatin clumps), apoptotic Ser-toli cells (highly condensed nuclei and nuclear membrane lysis) and necrotic Sertoli cells (marginated chromatins along the nuclear membrane, some swollen and ruptured cell organelles, e.g. mitochondria) could be identified. Conclusively, based on transmission electron microscopic observations, MEHP treatment may affect spermatogenic cells, and lead them to necrosis. Thus, testicular tissue cultures and cell cultures are of advantageous for screening testicular toxicity of chemicals. Phthalic acid esters have already been proved as a potential compound to reduce fertility, and induce testicular atrophy in laboratory animals (Thomas and Thomas, 1984). One of the most widely-studied male reproductive toxicants in rats is di(2-ethylhexyl) phthalate (DEHP) (Richburg and Boekelheide, 1996). Albro et al. (1973), Row-land et al. (1977), Lake et al. (1977), and Thomas and Thomas (1984) have reported that after oral administration, phthalates are rapidly hydrolyzed in gut and other tissues by nonspecific esterases to produce the corresponding monoester. Pollack et al. (1985) also have reported that mono(2-ethylhexyl) phthalate (MEHP) is one of the most potently occurring monoester and an ultimate tes-ticular toxic metabolite. Recently, research interest tends have changed from DEHP to MEHP. Although Richburg and Boekelheide (1996), and Suominen et al. (2003) have conducted MEHP experiments using labora-tory animals (in vivo), there is still lack of MEHP testing using the testicular tissue culture (in vitro). The tissue culture is advantageous to clarify the di-rect effects of chemicals on target cells. Therefore, in this study, prepubertal Sprague-Dawley (SD) rat testes were used to ascertain the effects of MEHP on rat testicular tissue culture (in vitro), with spe-cific focus on the morphological alterations of Ser-toli and spermatogenic cells.03/2004; 80(5-6):127-136.