A EXPOSIÇÃO PERINATAL AO BISFENOL A DURANTE O PERÍODO DA DIFERENCIAÇÃO SEXUAL HIPOTALÂMICA MODULA A EXPRESSÃO TESTICULAR DE GENES RELACIONADOS À ESPERMATOGÊNESE

• Autor(a) principal: CAMPOS, PATRÍCIA DE
• Data de Publicação: 2016
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações do UNICENTRO
• Texto Completo: http://tede.unicentro.br:8080/jspui/handle/jspui/688
• topic: Bisfenol A; Expressão gênica; Parâmetros espermáticos; Bisphenol A; Gene expression; Sperm parameters; CIENCIAS DA SAUDE::FARMACIA

The increased incidence of male reproductive disorders has attracted concerns about the impact of endocrine disrupting chemicals (EDCs) on reproductive health, especially when such exposure occurs during fetal life. Bisphenol A (BPA) is a EDC with recognized estrogenic activity, which is widely used in the manufacture of plastics and inner lining of food cans. Studies conducted previously demonstrated compromising in the spermatogenesis process in male rats exposed to BPA in adulthood. In this manner, the aim of this study was to investigate the reproductive toxicity in adult male offspring of dams exposed to BPA during the perinatal period from gestational day 18 to postnatal day (PND) 5, which is recognized as the hypothalamic sexual differentiation window. During this period, the dams were treated once a day with zero, 0.5 or 5 mg per kg of body weight, subcutaneously, of BPA diluted in corn oil. In PND90, the male offspring was euthanized and tissues were collected to evaluate the a) sperm production by counting the testicular sperm; b) sperm reserves by counting the epididymal sperm; c) sperm transit time by dividing sperm reserves by sperm production; d) functional evaluation of spermatozoa collected from cauda epididymis (acrosome integrity by Pope staining method, plasma membrane integrity by eosin-nigrosin staining method, mitochondrial activity by measuring cytochrome c oxidase activity in the mid-piece of sperm, and morphology after buffered formal-saline solution fixation); e) histology of the seminiferous epithelium in microscopic sections of testis fixed in Bouin’s solution and stained with periodic-acid-schiff (PAS); f) transcript expression androgen receptor (Ar), α estradiol receptor (Esr1), β estradiol receptor (Esr2), α estrogen receptor G protein coupled (Gper) and cytochrome P450 family 19, subfamily a, polypeptide 1 (Cyp419a1) in the testis by reverse transcription followed by quantitative PCR (RT-qPCR); and g) serum hormonal dosages of testosterone by electrochemiluminescence. Parametric data were analyzed using ANOVA followed by Tukey-HSD posthoc test and non-parametric data were analyzed using Kruskal-Wallis followed by Dunn’s posthoc test with resources of the software Statistica 7.0 (Statsoft Inc). Statistical differences were considered when p <0.05. BPA exposure during the perinatal development reduced total and daily sperm production in the adult male offspring. Morphological changes in the seminiferous epithelium also affected in both BPA treated groups, with a decrease in epithelium height and an increase in luminal diameter. The sperm transit time and sperm reserves increased in both BPA treated groups. The functionality of the sperm was only affected in the group treated with 5 mg of BPA/kg, with reduction in the integrity of acrosome and plasme membrane as well as reduced mitochondrial activity and increased morphological abnormalities. The pattern of expression of genes related to spermatogenesis process was altered only in the group treated with 5 mg of BPA/kg, with reduction in Ar mRNA and increasing in Esr1 mRNA. No significant alterations were observed in Cyp419a1, Esr2 or Gper mRNAs. The serum dosage of testosterone was increased in the group treated with 5 mg of BPA/kg. The reduction in the seminiferous epithelial height is possible related with the decrease in the sperm production by the testis. BPA caused an accumulation of sperm in the epididymis segments by increased the sperm transit time, which is evidenced by the increase in sperm reserves in both treated groups. In animals exposed to a higher dose increased testosterone levels and reduced Ar mRNA expression, which may negatively influence the response of testosterone on Sertoli cells. As result of disturbed spermatogenesis, all parameters of spermatic function were compromised, suggesting a possible impairment in the fecundation ability of this sperm. In conclusion, that exposure to doses 0,5 e 5 mg/ kg body weight/day of BPA during the hypothalamic sexual differentiation period produces deleterious effects on spermatogenesis in adult offspring.