The Effect of Resorcinol on Bovine Spermatozoa Parameters in Vitro

Resorcinol as "endocrine disrupting chemical": Are thyroid-related adverse effects adequately documented in reptiles? In vivo experimentation in lizard Podarcis siculus

The endocrine system and particularly thyroid hormones regulate almost all physiological processes in a timely manner in all vertebrates, from fish to reptiles to mammals, so risk assessment of endocrine disrupting chemicals (EDCs) is extremely important given their persistent presence in all environmental matrices. Resorcinol, as well as nonylphenol, octylphenol, and bisphenol A, F, S, are non-Halogenated Phenolic (non-HPCs) Chemicals known as EDCs. Resorcinol is a particular example in that most studies are based exclusively on humans while animal studies are few and often inadequate. The aim of this study was to assess the effects of exposure to different doses of resorcinol on the thyroid gland of the lizard Podarcis siculus during different periods of the thyroid gland activity cycle. Our results showed histopathologic changes in thyroid (follicular cell height increase and colloid area decrease), a thyroid weight increase in combination with serum T4 and T3 decrease, serum TSH, TRH increase in male lizards treated with 0.8,3.9,13.1, and 36.9 mg/kg/d of resorcinol. Besides, we also investigated the impacts of resorcinol treatments on hepatic 5'ORD (type II) deiodinase and hepatic content of T3 and T4. Our findings showed that they are in agreement with in vivo in humans and in rodents data and therefore, resorcinol in reptiles may meet the WHO definition of ECDs.

The effects of caffeine on the motility and viability of stallion spermatozoa at different temperature conditions

The purpose of this study was to evaluate the dose- and time-dependent effect of caffeine treatment on the motility and viability of stallion spermatozoa at different temperatures. Six dose groups (A to F) were established with changing caffeine concentrations (from 0.625 to 10 mg/mL). The control samples were prepared by diluting the ejaculate only with physiological salt solution. The samples were examined after 0, 1, 2 and 3 h of incubation at 5 °C and 37 °C. The motility parameters were evaluated by Computer Assisted Semen Analyzer (CASA) system, and the viability was assessed by the mitochondrial toxicity test at the end of the incubation. A positive effect of the lowest tested caffeine concentration on the motility parameters was observed throughout the incubation period at 5 °C. At the end of the 3h incubation, the viability in every sample in these groups, treated with any caffeine concentration, showed lower values compared to the control. At the higher incubation temperature (37 °C), caffeine positively affected the motility in samples B (P < 0.05) and D, E, F (P < 0.001) after 3 h of incubation; however, the viability showed a slightly decreasing tendency. Our results suggest that caffeine, in an optimal concentration, may be used as a component of stallion semen extenders.

Revealing the binding properties between resorcinol and DNA

Resorcinol (1,3-dihydroxybenzene) is a common coupling agent in permanent hair dyes, and has arrested people's attention for its potential hazard to human health. However, the action mechanism of resorcinol and human DNA has not been elucidated. In this research, the binding properties between resorcinol and calf thymus DNA (ct-DNA) were studied for the first time through various spectral and molecular docking techniques. Spectral studies showed that the initial fluorescence quenching of resorcinol against DNA was a static one. The result of ΔH < 0 and ΔS > 0 was produced from thermodynamic experimental data, therefore it could be concluded that electrostatic force was the major driving force, while binding constant K_b was 1.56 × 10⁴  M^-1 at 298 K. The electrostatic binding network between resorcinol and ct-DNA was established explicitly through competitive substitution analysis and other spectral approaches. The results of FT-IR absorption spectra indicated that resorcinol had bound to the DNA phosphate skeleton. Molecular docking clearly revealed that binding occurred between hydroxyl groups of resorcinol and phosphorus oxygen bonds (P-O) of the DNA skeleton. These findings may deepen our understanding of the action mechanism between resorcinol and ct-DNA and provide some useful data on the effect of resorcinol on human diseases.