ZeTox – Toxicology Services

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icon-reproduction-tox ReproductionTox – Reproduction Toxicology

The assessment of animal reproductive performance (both for males and females) is essential in the ecotoxicology field. There is proven evidence that some chemicals can affect sexual function, fertility, and development in animals. Therefore, reproductive and developmental toxicology remains an evolving field that is constantly under public scrutiny. As technology and scientific knowledge advance, regulatory agencies are demanding new types of data derived from studies that minimize animals' use following the 3 R's: replacement, reduction, and refinement. Zebrafish is the best tool to achieve this.

Advantages

In vivo assessment of compounds disruptive power in complete organisms.

Reproductive and developmental toxicology is easy to test in zebrafish.

Method description

This test has been adapted to adult zebrafish from the OECD421 guideline for reproduction toxicity.

Figure: Schematic design of the methodology that can be applied in zebrafish.

Readouts

We analyze several parameters as bodyweight changes of the adults during the assay, egg production, fertilization rate, hatching rate, the number of ovulated eggs, the toxic response data by sex and dose, the gonadosomatic index (GSI), and the hepatosomatic index (HSI), 17β-estradiol (E2), testosterone (T), and vitellogenin (Vtg) concentrations. Also, histological alterations in the gonads and livers could be measured. At the end of all tests, ovaries and sperm tissues will be collected, and mRNAs will be extracted for retrotranscription. cDNA will be used for qRT-PCR to analyze the expression of specific markers.

References

  1. Test No. 421: Reproduction/Developmental Toxicity Screening Test. OECD Guidelines for the Testing of Chemicals, Section 4
  2. Cao et al. Reproductive toxicity of azoxystrobin to adult zebrafish (Danio rerio). Environ Pollut. 2016 Dec;219:1109-1121. doi: 10.1016/j.envpol.2016.09.015. Epub 2016 Sep 8.
  3. Horzmann and Freeman. Making Waves: New Developments in Toxicology With the Zebrafish. Toxicol Sci. 2018 May 1;163(1):5-12. doi: 10.1093/toxsci/kfy044.