Reproductive expression dynamics and comparative toxicological perspective of beta estrogen receptor gene in the male wall lizard, Podarcis sicula Rafinesque, 1810 (Chordata: Reptilia)

Abstract

Over the last few decades, due to its relevant function in male reproduction assessment, important molecular achievements have been made in the molecular characterization of estrogen receptor genes in various species. Our work focuses on a male seasonal breeder, the bioindicator Podarcis sicula, because of its peculiar gonadal anatomy, similar to that of humans. Based on the cloned lizard's gene sequence fragment of estrogen receptor beta, esr2 (GenBank JN705543.1), we found DNA binding domain identity of 99% as well as a homologous sequence with humans. Furthermore, in order to better illustrate how this gene is regulated in the lizard's reproductive system organs, we investigated the transcriptional activity of esr2 in brain and testis tissues during mating and winter stasis phases of the reproductive cycle. Quantitative real time-polymerase chain reaction (qRT-PCR) analyses performed on male gonadal tissues demonstrate a significant increase in esr2 expression during mating compared to the winter stasis period, while in the brain, esr2 shows the opposite trend. Next, we provide morphological evidence of the detrimental effect on spermatogenesis of a pure anti-estrogen treatment (ICI 182,780) and the corresponding effect on esr2 expression in lizard specimens during the mating period which, upon treatment, was found to be no different from the expression levels in winter stasis both in the brain and in the testis. In this study, we explore the potential use of Podarcis sicula as a model for human testis development and maturation, as well as esr2 expression for toxicological screening in one-testis gonadectomy.

Antioxidative Defense and Fertility Rate in the Assessment of Reprotoxicity Risk Posed by Global Warming

“…Drug exposure in the maturation stage during the hottest time period, with the aim of mimicking emerging estrogenic pollutants in the environment, showed a slowing of spermatogenesis processes into seminiferous tubules, a reduced lumen, and a depletion of sperm quantity. Testicular changes and spermatogenesis arrest at secondary spermatocyte levels were observed, highlighting a reorganization of testicular structure impacting male fertility [98].…”

“…Analyses on Reptilia Squamata, such as on the ruin Lacertidae, Podarcis sicula, showed how combined factors, as well as high temperature and the activity of xenobiotics released into the environment, affect their physiology [5,98]. Specifically, the antioxidant defense activity by glutathione peroxidase 4 (gpx4), which was observed under steroid control [131,132], showed that over-expression in the testis is followed by an opposite trend in relation to the feedback of the brain (hypothalamus-pituitary)-gonad axis, indicating steroid control [5,85].…”

“…Brain gpx4 expression showed statistically significant differences at different temperatures, but opposite trends in the testis and altered expression in both tissues, with evidence of testis morphological and DNA disruption. This could be explained by gpx4, which, as part of a survival mechanism, is switched on by exogenous stressors and counteracts stress-induced apoptosis [19,98].…”

Seasonal and pharmaceutical‐induced changes in selenoprotein glutathione peroxidase 4 activity in the reproductive dynamics of the soil biosentinel Podarcis sicula (Chordata: Reptilia)

“…In the brain adaptation the steroids, for example, play an important role because these hormones are secreted in response to environmental signals that are processed by the nervous system and then act back on specific areas to modify their function (reviewed in Guerriero, ). Because changes in the development, adult life, and degree of environmental pollution can alter genomic activity, steroid hormones as well as steroid receptors, and antioxidants under steroid control give us unique insight into the role of the genome in the control of brain reproductive and nonreproductive function (Guerriero, Di Giaimo, et al, ; Guerriero, Roselli, & Ciarcia, ; Guerriero, Trocchia, Abdel‐Gawad, & Ciarcia, ). Selenoproteins are part of the antioxidant network, which consists of nonenzymatic antioxidant compounds and a large number of redox‐active enzymes.…”

Environmental-Friendly Contamination Assessment of Habitats Based on the Trace Element Content of Dragonfly Exuviae

“…They also enter humans through the food chain [2]. For an environmentally friendly assessment of contamination, tissues such as blood plasma of fish [3], frog skin by biopsy [4], lizard single gonadectomy [5], bird fece [6] and feather [7] may be useful. Among invertebrates, the aquatic insects are key biotransporters of contaminants between aquatic and terrestrial ecosystems [8,9].…”