New approach for reproductive toxicity assessment: chromatoid bodies as a target for methylmercury and polychlorinated biphenyls in prepubertal male rats

Author(s)

Garcia, M. S. ^{[1, 2]} ; Orcini, W. A. ^[3] ; Peruquetti, R. L. ^{[1, 3, 4]} ; Perobelli, J. E. ^[2]

Affiliation

^[1] Sagrado Coracao Univ, Sch Hlth Sci, Rua Irma Arminda, 10-50 Jd, BR-17011160 Bauru, SP - Brazil

^[2] Univ Fed Sao Paulo, Dept Marine Sci, Expt Toxicol Lab, Campus Baixada Santista, 144 Encruzilhada, BR-11070102 Santos, SP - Brazil

^[3] Sagrado Coracao Univ, Mol Biol & Cytogenet Lab, Rua Irma Arminda, 10-50 Jd, BR-17011160 Bauru, SP - Brazil

^[4] Sagrado Coracao Univ, Off Associate Dean Grad Studies & Res, Rua Irma Arminda, 10-50 Jd, BR-17011160 Bauru, SP - Brazil

• Document type: Journal article
• Source: REPRODUCTION FERTILITY AND DEVELOPMENT; v. 32, n. 10, p. 914-922, 2020.
• Web of Science Citations: 0

Abstract

This study investigated the reproductive toxicity of methylmercury (MeHg) and Aroclor (Sigma-Aldrich), alone or in combination, following exposure of prepubertal male rats considering the chromatoid body (CB) as a potential target. The CB is an important molecular regulator of mammalian spermatogenesis, primarily during spermatid cytodifferentiation. Male Wistar rats were exposed to MeHg and/or Aroclor, according the following experimental design: control group, which was administered in corn oil (vehicle) only; MeHg-treated group, which was administered 0.5 mg kg(-1) day(-1) MeHg; Aroclor-treated group, which was administered 1mg kg(-1) day(-1) Aroclor; Mix-LD, group which was administered a low-dose mixture of MeHg (0.05 mg kg(-1) day(-1)) and Aroclor (0.1 mg kg(-1) day(-1)); and MixHD group, which was administered a high-dose mixture of MeHg (0.5 mg kg(-1) day(-1)) and Aroclor (1.0 mg kg(-1) day(-1)). MeHg was diluted in distilled water and Aroclor was made up in corn oil (volume 1mL kg(-1)). Rats were administered the different treatments from PND23 to PND53 by gavage. The morphophysiology of CBs was analysed, together with aspects of steroid hormones status and regulation, just after the last treatment on PND53. In addition, the long-term effects on sperm parameters were assessed in adult animals. MeHg exposure increased mouse VASA homologue (MVH) protein levels in seminiferous tubules, possibly affecting the epigenetic status of germ cells. Aroclor produced morphological changes to CB assembly, which may explain the observed morphological defects to the sperm flagellum and the consequent decrease in sperm motility. There were no clear additive or synergistic effects between MeHg and Aroclor when administered in combination. In conclusion, this study demonstrates that MeHg and Aroclor have independent deleterious effects on the developing testis, causing molecular and morphological changes in CBs. To the best of our knowledge, this is the first study to show that CBs are targets for toxic agents. (AU)

• FAPESP's process: 16/04580-0 - Decifring the role of transient proteins in the chromatoid bodies molecular composition: Fibrillarin (nucleolar component) and CLOCK/BMAL1 (circadian proteins).
• Grantee: Rita Luiza Peruquetti
• Support Opportunities: Regular Research Grants
• FAPESP's process: 13/14477-3 - Prepubertal exposure to low doses of associated methylmercury and aroclor: evaluation of reproductive and endocrine parameters of pubescent and adult male rats
• Grantee: Juliana Elaine Perobelli
• Support Opportunities: Regular Research Grants
• FAPESP's process: 13/26797-2 - Prepubertal exposure to low doses of associated methylmercury and aroclor: evaluation of reproductive parameters of pubescent and adult male rats
• Grantee: Mariana Simões Garcia
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 12/22009-7 - Distribution of nucleolar protein fibrillarin in the seminiferous epithelium of mammals and its role in the chromatoid bodies physiology
• Grantee: Rita Luiza Peruquetti
• Support Opportunities: Regular Research Grants