title: The impact of long-term exposure to space environment on adult mammalian organisms: a study on mouse thyroid and testis.
abstract: Hormonal changes in humans during spaceflight have been demonstrated but the underlying mechanisms are still unknown. To clarify this point thyroid and testis/epididymis, both regulated by anterior pituitary gland, have been analyzed on long-term space-exposed male C57BL/10 mice, either wild type or pleiotrophin transgenic, overexpressing osteoblast stimulating factor-1. Glands were submitted to morphological and functional analysis.In thyroids, volumetric ratios between thyrocytes and colloid were measured. cAMP production in 10(-7)M and 10(-8)M thyrotropin-treated samples was studied. Thyrotropin receptor and caveolin-1 were quantitized by immunoblotting and localized by immunofluorescence. In space-exposed animals, both basal and thyrotropin-stimulated cAMP production were always higher. Also, the structure of thyroid follicles appeared more organized, while thyrotropin receptor and caveolin-1 were overexpressed. Unlike the control samples, in the space samples thyrotropin receptor and caveolin-1 were both observed at the intracellular junctions, suggesting their interaction in specific cell membrane microdomains.In testes, immunofluorescent reaction for 3β- steroid dehydrogenase was performed and the relative expressions of hormone receptors and interleukin-1β were quantified by RT-PCR. Epididymal sperm number was counted. In space-exposed animals, the presence of 3β and 17β steroid dehydrogenase was reduced. Also, the expression of androgen and follicle stimulating hormone receptors increased while lutenizing hormone receptor levels were not affected. The interleukin 1 β expression was upregulated. The tubular architecture was altered and the sperm cell number was significantly reduced in spaceflight mouse epididymis (approx. -90% vs. laboratory and ground controls), indicating that the space environment may lead to degenerative changes in seminiferous tubules.Space-induced changes of structure and function of thyroid and testis/epididymis could be responsible for variations of hormone levels in human during space missions. More research, hopefully a reflight of MDS, would be needed to establish whether the space environment acts directly on the peripheral glands or induces changes in the hypotalamus-pituitary-glandular axis.
authors.affiliation: DIPTERIS, University of Genoa, Genova, Italy.
authors.forename: Maria Angela
authors.initials: MA
authors.lastname: Masini
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Albi
authors.forename: Cristina
authors.initials: C
authors.lastname: Barmo
authors.forename: Tommaso
authors.initials: T
authors.lastname: Bonfiglio
authors.forename: Lara
authors.initials: L
authors.lastname: Bruni
authors.forename: Laura
authors.initials: L
authors.lastname: Canesi
authors.forename: Samuela
authors.initials: S
authors.lastname: Cataldi
authors.forename: Francesco
authors.initials: F
authors.lastname: Curcio
authors.forename: Marta
authors.initials: M
authors.lastname: D'Amora
authors.forename: Ivana
authors.initials: I
authors.lastname: Ferri
authors.forename: Katsumasa
authors.initials: K
authors.lastname: Goto
authors.forename: Fuminori
authors.initials: F
authors.lastname: Kawano
authors.forename: Remo
authors.initials: R
authors.lastname: Lazzarini
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Loreti
authors.forename: Naoya
authors.initials: N
authors.lastname: Nakai
authors.forename: Takashi
authors.initials: T
authors.lastname: Ohira
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Ohira
authors.forename: Silvio
authors.initials: S
authors.lastname: Palmero
authors.forename: Paola
authors.initials: P
authors.lastname: Prato
authors.forename: Franco
authors.initials: F
authors.lastname: Ricci
authors.forename: Linda
authors.initials: L
authors.lastname: Scarabelli
authors.forename: Tsubasa
authors.initials: T
authors.lastname: Shibaguchi
authors.forename: Renza
authors.initials: R
authors.lastname: Spelat
authors.forename: Felice
authors.initials: F
authors.lastname: Strollo
authors.forename: Francesco Saverio
authors.initials: FS
authors.lastname: Ambesi-Impiombato
mesh_terms: D000818:Animals; D015153:Blotting, Western; D051242:Caveolin 1 / Q000378:metabolism; D000242:Cyclic AMP / Q000096:biosynthesis; D005455:Fluorescent Antibody Technique; D007150:Immunohistochemistry; D053583:Interleukin-1beta / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011987:Receptors, Steroid / Q000378:metabolism; D011989:Receptors, Thyrotropin / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013026:Space Flight; D013076:Sperm Count; D013737:Testis / Q000166:cytology* / Q000378:metabolism*; D013961:Thyroid Gland / Q000166:cytology* / Q000378:metabolism*
chemical_list: D051242:Caveolin 1; D053583:Interleukin-1beta; D011987:Receptors, Steroid; D011989:Receptors, Thyrotropin; D000242:Cyclic AMP