Prenatal developmental toxicity testing of petroleum substances using the zebrafish embryotoxicity test.

Lenny Kamelia

doi:10.14573/altex.1808121

Abstract

The present study evaluates the applicability of the zebrafish embryotoxicity test (ZET) to assess prenatal developmental toxicity (PDT) potency of the DMSO-extracts of 9 petroleum substances (PS), with variable polycyclic aromatic hydrocarbon (PAH) content, and 2 gas-to-liquid (GTL) products, without any PAHs but otherwise similar properties to PS. The results showed that all PS extracts induced concentration-dependent in vitro PDT, as quantified in the ZET and that this potency is associated with their 3-5 ring PAH content. In contrast and as expected, GTL products did not induce any effect at all. The potencies obtained in the ZET correlated with those previously reported for the embryonic stem cell test (EST) (R2=0.61), while the correlation with potencies reported in in vivo studies were higher for the EST (R2=0.85) than the ZET (R2=0.69). Combining the results of the ZET with those previously reported for the EST (Kamelia et al., 2017), the aryl hydrocarbon (AhR) CALUX assay (Kamelia et al., 2018), and the PAH content, ranked and clustered the test compounds in line with their in vivo potencies and chemical characteristics. To conclude, our findings indicate that the ZET does not outperform the EST as a stand-alone assay for testing PDT of PS, but confirms the hypothesis that PAHs are the major inducers of PDT by some PS, while they also indicate that the ZET is a useful addition to a battery of in vitro tests able to predict the in vivo PDT of PS.

Highlights

Petroleum substances (PS) are UVCBs and regulated as such under the European Union (EU) REACH legislation (Registration, Evaluation,Authorisation, and Restriction of Chemicals)
Published in vivo studies show that some PS are able to cause prenatal developmental toxicity (PDT) in pregnant rats, and it is suspected that this adverse effect is induced by specific constituents present in these substances, mainly 3- to 7-ring polycyclic aromatic hydrocarbon (PAH) (Feuston et al, 1994; Murray et al, 2013)
The present study evaluates the applicability of the zebrafish embryotoxicity test (ZET) to assess PDT potency of the DMSO-extracts of 9 PS and 2 GTL products

Summary

Introduction

Petroleum substances (PS) are UVCBs (substances of Unknown or Variable composition, Complex reaction products and Biological materials) and regulated as such under the European Union (EU) REACH legislation (Registration, Evaluation,Authorisation, and Restriction of Chemicals). One of the consequences is that most PS (186 currently active registered EINECS numbers, all with a volume of > 1000 tons/ year) will need to be tested for their potential adverse effect on prenatal development according to the Organisation for Economic Co-operation and Development (OECD) 414 testing guideline. This would require substantial numbers of experimental animals (> 2500 animals/test/compound; OECD, 2001) and involve a considerable amount of resources, both monetary and in terms of capacity (van der Jagt et al, 2004; Rovida et al, 2011). The use of a battery of in vitro alternative assays, such as the zebrafish embryotoxicity test (ZET; Sipes et al, 2011; Strähle et al, 2012) and/or the embryonic stem cell test (EST; Spielmann, 2009), to group PS into a limited number of categories and/or to facilitate read-across from PS for which in vivo PDT data are already available, may reduce the number of animals and resources needed to study PDT potencies of PS

Methods

Results

Conclusion