title: Ovarian down Regulation by GnRF Vaccination Decreases Reproductive Tract Tumour Size in Female White and Greater One-Horned Rhinoceroses.
abstract: Reproductive tract tumours, specifically leiomyoma, are commonly found in female rhinoceroses. Similar to humans, tumour growth in rhinoceroses is thought to be sex hormone dependent. Tumours can form and expand from the onset of ovarian activity at puberty until the cessation of sex-steroid influences at senescence. Extensive tumour growth results in infertility. The aim of this study was to down regulate reproductive function of tumour-diseased and infertile females to stop further tumour growth using a Gonadotropin releasing factor (GnRF) vaccine. Four infertile southern white (Ceratotherium simum simum) and three Greater one-horned rhinoceroses (rhinoceros unicornis) with active ovaries and 2.7 ± 0.9 and 14.0 ± 1.5 reproductive tract tumours respectively were vaccinated against GnRF (Improvac®, Zoetis, Germany) at 0, 4 and 16 weeks and re-boostered every 6-8 months thereafter. After GnRF vaccination ovarian and luteal activity was suppressed in all treated females. Three months after vaccination the size of the ovaries, the number of follicles and the size of the largest follicle were significantly reduced (P<0.03). Reproductive tract tumours decreased significantly in diameter (Greater-one horned rhino: P<0.0001; white rhino: P<0.01), presumably as a result of reduced sex-steroid influence. The calculated tumour volumes were reduced by 50.8 ± 10.9% in Greater one-horned and 48.6 ± 12.9% in white rhinoceroses. In conclusion, GnRF vaccine effectively down regulated reproductive function and decreased the size of reproductive tract tumours in female rhinoceros. Our work is the first to use down regulation of reproductive function as a symptomatic treatment against benign reproductive tumour disease in a wildlife species. Nonetheless, full reversibility and rhinoceros fertility following GnRF vaccination warrants further evaluation.
authors.affiliation: Leibniz Institute for Zoo and Wildlife Research, PF 700430, D-10342 Berlin, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Hermes
authors.affiliation: University of Veterinary Medicine, Biomedical Sciences, Veterinärplatz 1, 1210 Vienna, Austria.
authors.forename: Franz
authors.initials: F
authors.lastname: Schwarzenberger
authors.affiliation: Leibniz Institute for Zoo and Wildlife Research, PF 700430, D-10342 Berlin, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Göritz
authors.affiliation: Singapore Zoological Gardens, 80 Mandai Lakeroad, Singapore 729826, Singapore.
authors.forename: Serena
authors.initials: S
authors.lastname: Oh
authors.affiliation: Lisbon Zoo, Veterinary Hospital, Estrada de Benfica, n°158-160 Lisbon, Portugal.
authors.forename: Teresa
authors.initials: T
authors.lastname: Fernandes
authors.affiliation: Lisbon Zoo, Veterinary Hospital, Estrada de Benfica, n°158-160 Lisbon, Portugal.
authors.forename: Rui
authors.initials: R
authors.lastname: Bernardino
authors.affiliation: ZooParc de Beauval, 41110 Saint-Aignan, France.
authors.forename: Antoine
authors.initials: A
authors.lastname: Leclerc
authors.affiliation: Thoiry Zoo, 78770 Thoiry, France.
authors.forename: Eva
authors.initials: E
authors.lastname: Greunz
authors.affiliation: Singapore Zoological Gardens, 80 Mandai Lakeroad, Singapore 729826, Singapore.
authors.forename: Abraham
authors.initials: A
authors.lastname: Mathew
authors.affiliation: Colchester Zoo, Maldon Road, Stanway, Essex CO3 0SL, United Kingdom.
authors.forename: Sarah
authors.initials: S
authors.lastname: Forsyth
authors.affiliation: Leibniz Institute for Zoo and Wildlife Research, PF 700430, D-10342 Berlin, Germany.
authors.forename: Joseph
authors.initials: J
authors.lastname: Saragusty
authors.affiliation: Leibniz Institute for Zoo and Wildlife Research, PF 700430, D-10342 Berlin, Germany.
authors.forename: Thomas Bernd
authors.initials: TB
authors.lastname: Hildebrandt
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D015536:Down-Regulation; D005243:Feces / Q000737:chemistry; D005260:Female; D005833:Genital Neoplasms, Female / Q000000981:diagnostic imaging / Q000276:immunology* / Q000473:pathology*; D007987:Gonadotropin-Releasing Hormone / Q000276:immunology*; D010053:Ovary / Q000378:metabolism*; D010527:Perissodactyla; D012098:Reproduction; D047368:Tumor Burden / Q000276:immunology*; D014463:Ultrasonography; D014611:Vaccination
chemical_list: D007987:Gonadotropin-Releasing Hormone