RESUMO

Here, we analyzed the recovery of the reproductive capability in male Cichlasoma dimerus after exposure to sublethal concentrations of 4-tert-octylphenol (OP), a demonstrated estrogenic chemical. Adult fish were exposed to 0, 30, 150 and 300 µg/L OP during 60 days and subsequently transferred to OP-free water for another 60 days. At 150 and 300 µg/L, absence of fertilized spawnings were recorded during the first 4 weeks following OP exposure, which could be explained by the impairment of testis architecture recorded at the highest OP concentrations. The restoration of the testicular organization began by day 14 in OP-free water, when the germinal epithelium re-started to proliferate. Testicular functionality was recovered by day 28, yielding fertilized eggs and viable F1 embryos. These results show that pathological features induced in the testes of C. dimerus by OP exposure are not permanent since fish recover their fertilization capacity after an adequate depuration period.

Assuntos

Ciclídeos/fisiologia , Estrogênios/toxicidade , Fenóis/toxicidade , Reprodução/efeitos dos fármacos , Testículo/efeitos dos fármacos , Animais , Masculino , Testículo/patologia

RESUMO

Exposure to environmental pollutants may disrupt endocrine functions and cause reproductive effects in human and wildlife populations. Various groups of chemicals have estrogen-like effects, including degradation products of alkylphenol polyethoxylates, such as 4-tert-octylphenol (OP). Laboratory studies have shown that exposure of male fish to xenoestrogens results in induction of circulating vitellogenin (Vtg), inhibition of testicular growth, testis abnormalities and formation of intersex gonads. In this study, the impact of the exposure to waterborne OP on reproductive aspects in the South American cichlid fish Cichlasoma dimerus was evaluated using qualitative changes in the levels of Vtg in plasma and surface mucus and histological alterations in the liver and gonads as endpoints. Adult males and females were exposed to OP via immersion during 60 days in aquaria under semi-static conditions, water changes being made every 84 h. Treatment groups were: control (ethanol 0.005%), OP 30, 150 and 300 microg/L. Using Western and Dot blot analysis, Vtg was detected in plasma and mucus of control and treated females and treated males, while no Vtg was observed in samples from control males. Morphological changes in the hepatocytes due to the accumulation of Vtg were observed in OP-exposed males. Impairment of testicular structure became apparent in males treated with the highest OP concentrations. The most salient pathological change was the alteration of lobular organization with increased testicular fibrosis and progressive disruption of spermatogenesis. No major changes were observed in ovarian architecture. Our results indicate that detection of Vtg in surface mucus may be a sensitive and non-invasive biomarker of the endocrine disrupting effects of environmental estrogens, resulting in a useful method for field monitoring.

Assuntos

Disruptores Endócrinos/toxicidade , Proteínas de Peixes/metabolismo , Fígado/efeitos dos fármacos , Perciformes/metabolismo , Fenóis/toxicidade , Testículo/efeitos dos fármacos , Vitelogeninas/metabolismo , Poluentes Químicos da Água/toxicidade , Animais , Argentina , Biomarcadores/metabolismo , Relação Dose-Resposta a Droga , Monitoramento Ambiental/métodos , Feminino , Fibrose , Proteínas de Peixes/sangue , Água Doce , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Fígado/metabolismo , Fígado/patologia , Masculino , Muco/metabolismo , Espermatogênese/efeitos dos fármacos , Testículo/metabolismo , Testículo/patologia , Fatores de Tempo , Vitelogeninas/sangue

RESUMO

Synbranchus marmoratus, is a protogynic diandric species in which two types of males, primary and secondary, are found. In both types, the germinal compartment in the testes is of the unrestricted lobular type, but in secondary (sex reversed females) males the lobules develop within the former ovarian lamellae. In the present study, the germinal compartment was examined in both types of males using light microscopy as well as scanning and transmission electron microscopy. Germinal compartment is limited by a basement membrane and contains Sertoli and germ cells. During maturation, processes of Sertoli cells form the borders of spermatocysts containing isogenic germ cells. Characteristically, type A and type B spermatogonia have a single nucleolus and grouped mitochondria associated with dense bodies or nuage. Type B spermatogonia, spermatocytes and spermatids are joined by cytoplasmatic bridges and are confined within spermatocysts. Secondary spermatocytes are difficult to find, indicating that this stage is of short duration. Biflagellated spermatozoa have a rounded head, no acrosome, and possess a midpiece consisting of two basal bodies, each of which produces a flagellum with a typical 9+2 microtubular composition. No associations occur between sperm and Sertoli cells. There were no differences between spermatogenesis in primary and secondary males in this protogynic, diandric fish.

Assuntos

Smegmamorpha/anatomia & histologia , Testículo/ultraestrutura , Animais , Feminino , Organismos Hermafroditas , Masculino , Microscopia Eletrônica , Microscopia Eletrônica de Varredura , Células de Sertoli/ultraestrutura , Processos de Determinação Sexual , Smegmamorpha/fisiologia , Espermatogênese/fisiologia , Testículo/fisiologia

RESUMO

The adenohypophysis of the cichlid fish Cichlasoma dimerus was studied using the avidin-biotin-peroxidase method with antisera raised against piscine pituitary hormones and heterologous antisera against mammalian pituitary hormones. Antiserum raised against rabbit ACTH recognized a group of cells bordering the neurohypophysis (NH) in the rostral pars distalis (RPD). Anti-chum salmon prolactin (PRL) identified a compact group of cells in the periphery of the RPD. Gonadotropin II (GTH II), thyrotropin (TSH) and growth hormone (GH)-ir cells were localized in the proximal pars distalis. Ir-GTH II cells were also observed in the dorsal area of the pars intermedia (PI). Ir-GTH I cells could not be identified using anti-chum salmon GTH I, this may be due either to a failure of the antisera to recognize the gonadotropin or to a low expression of the hormone in adults of this species. PAS positive cells from the PI bound specifically with three different antisera raised against somatolactin (SL) of four different fish species. These cells surrounded deep branches of the NH in the PI.

Assuntos

Percas/anatomia & histologia , Adeno-Hipófise/química , Adeno-Hipófise/citologia , Hormônio Adrenocorticotrópico/análise , Animais , Proteínas de Peixes , Glicoproteínas/análise , Gonadotropinas/análise , Hormônio do Crescimento/análise , Humanos , Imuno-Histoquímica , Neurônios/citologia , Hormônios Hipofisários/análise , Prolactina/análise , Tireotropina/análise

RESUMO

The adenohypophysis of the cichlid fish Cichlasoma dimerus was studied using the avidin-biotin-peroxidase method with antisera raised against piscine pituitary hormones and heterologous antisera against mammalian pituitary hormones. Antiserum raised against rabbit ACTH recognized a group of cells bordering the neurohypophysis (NH) in the rostral pars distalis (RPD). Anti-chum salmon prolactin (PRL) identified a compact group of cells in the periphery of the RPD. Gonadotropin II (GTH II), thyrotropin (TSH) and growth hormone (GH)-ir cells were localized in the proximal pars distalis. Ir-GTH II cells were also observed in the dorsal area of the pars intermedia (PI). Ir-GTH I cells could not be identified using anti-chum salmon GTH I, this may be due either to a failure of the antisera to recognize the gonadotropin or to a low expression of the hormone in adults of this species. PAS positive cells from the PI bound specifically with three different antisera raised against somatolactin (SL) of four different fish species. These cells surrounded deep branches of the NH in the PI.