Alkyphenol Exposure Alters Steroidogenesis in Male Lizard Podarcis siculus

SIMPLE SUMMARY: The non-stop release and increase in the ecosystem of toxic and polluting substances such as endocrine disrupting chemicals pose a threat to the survival of wildlife. Nonylphenol and Octylphenol are well known xenobiotics, with estrogen-like properties, widely used to optimize the manufacturing of different products, and due to their hydrophobicity and low solubility, they are persistent and ubiquitous in many environmental matrices. The goal of the present study was to investigate the effects of these compounds on the testis of the lizard Podarcis siculus during the reproductive period, focusing our attention on the steroidogenesis process. The lizard P. siculus has been chosen as animal model as it is usually used as a sentinel species and because the morphology and physiology of testis between lizards and mammals do not change, allowing a fine correlation of observed effects to human health. Obtained results showed that both substances used in this study, are able to alter testis histology and localization of key steroidogenic enzymes such as 3β-hydroxysteroid dehydrogenase, 17β-hydroxysteroid dehydrogenase and P450 aromatase, which represents the major target of these two alkylphenols. In conclusion, Nonylphenol and Octylphenol inhibit steroidogenesis, interfering with the reproductive capacity of the lizard Podarcis siculus. ABSTRACT: Background: Nonylphenol (NP) and Octylphenol (OP) are persistent and non-biodegradable environmental contaminants classified as endocrine disruptor chemicals (EDCs). These compounds are widely used in several industrial applications and present estrogen-like properties, which have extensively been studied in aquatic organisms. The present study aimed to verify the interference of these compounds alone, and in mixture, on the reproductive cycle of the male terrestrial vertebrate Podarcis siculus, focusing mainly on the steroidogenesis process. Methods: Male lizards have been treated with different injections of both NP and OP alone and in mixture, and evaluation has been carried out using a histological approach. Results: Results obtained showed that both substances are able to alter both testis histology and localization of key steroidogenic enzymes, such as 3β-hydroxysteroid dehydrogenase (3β-HSD), 17β- hydroxysteroid dehydrogenase (17β-HSD) and P450 aromatase. Moreover, OP exerts a preponderant effect, and the P450 aromatase represents the major target of both chemicals. Conclusions: In conclusion, NP and OP inhibit steroidogenesis, which in turn may reduce the reproductive capacity of the specimens.