title: Acute and long-term effects of in utero exposure of rats to di(n-butyl) phthalate on testicular germ cell development and proliferation.
abstract: This study investigated effects of in utero exposure [embryonic day (e)13.5-e21.5] to di(n-butyl) phthalate (DBP) on fetal gonocytes and postnatal germ cell (GC) development in rats and focused on changes (delayed development) relevant to the postulated origins of human carcinoma-in situ cells. DBP treatment resulted in both early (e15.5-e17.5) and late (e19.5-e21.5) effects on gonocytes. The former involved delayed entry of proliferating gonocytes into quiescence, as indicated by prolongation/overexpression of octamer-binding transcription factor 3/4 and retinoblastoma protein phosphorylated at Ser 807/811 and Ki67 plus a 2- to 4-fold increase in gonocyte apoptosis. The late effect of DBP was to induce a greater than 10-fold increase in occurrence of multinucleated gonocytes. GC numbers in DBP-exposed males were reduced (P < 0.01) by 37, 53, 79, and 80% at e21.5 and postnatal d (d) 4, 8, and 15, respectively, with recovery to normal in scrotal testes between postnatal d 25 and 90. The DBP-induced decrease in GC numbers at d 4-8 was associated with delayed exit from quiescence, as indicated by retinoblastoma protein expression and a 28% reduction (P < 0.001) in GC proliferation index at d 6, although the latter was increased by 84% at d 25. The postnatal GC changes were associated with the early, but not late, effects of DBP on gonocytes as short-term DBP treatment from e19.5 to e20.5, induced multinucleated gonocytes as effectively as did treatment from e13.5 to e20.5, but did not reduce GC numbers on d 4. In conclusion, fetal DBP exposure delays normal GC development in both fetal (as early as e15.5) and postnatal life with the possibility of consequences for fertility.
authors.affiliation: Medical Research Council Human Reproductive Sciences Unit, Centre for Reproductive Biology, The Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, Scotland, United Kingdom.
authors.forename: Diana
authors.initials: D
authors.lastname: Ferrara
authors.forename: Nina
authors.initials: N
authors.lastname: Hallmark
authors.forename: Hayley
authors.initials: H
authors.lastname: Scott
authors.forename: Richard
authors.initials: R
authors.lastname: Brown
authors.forename: Chris
authors.initials: C
authors.lastname: McKinnell
authors.forename: I Kim
authors.initials: IK
authors.lastname: Mahood
authors.forename: Richard M
authors.initials: RM
authors.lastname: Sharpe
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D003993:Dibutyl Phthalate / Q000633:toxicity*; D005260:Female; D005333:Fetus / Q000187:drug effects*; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis; D008297:Male; D050814:Octamer Transcription Factor-3 / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D016160:Retinoblastoma Protein / Q000032:analysis; D013076:Sperm Count; D013091:Spermatogenesis / Q000187:drug effects*; D013094:Spermatozoa / Q000187:drug effects / Q000473:pathology; D013737:Testis / Q000187:drug effects* / Q000473:pathology
chemical_list: D019394:Ki-67 Antigen; D050814:Octamer Transcription Factor-3; D016160:Retinoblastoma Protein; D003993:Dibutyl Phthalate