Palladium nanoparticle effects on endocrine reproductive system of female rats

Abstract

The widespread industrial application of nanomaterials (NMs) has dramatically increased the likelihood of environmental and occupational exposure of humans to such xenobiotics. This issue, together with the increasing public health interest in understanding the effects of chemicals on endocrine system, encouraged to investigate the disruptive potential of NMs on the endocrine function. Therefore, the aim of this study was to evaluate the effects of palladium nanoparticles (Pd-NPs) on the female reproductive system of Wistar rats, intravenously exposed to different doses (0.12, 1.2, and 12 µg/kg), through the assessment of possible quantitative changes in the serum concentrations of several sex hormones. Our results demonstrated that the highest exposure doses significantly reduced the estradiol and testosterone concentrations, while increased the luteinizing hormone levels in treated animals compared to controls. Such alterations are indicative for an abnormal reproductive axis function. However, further investigations are needed to clarify the role of the different NP physicochemical properties in determining such effects, and possible underlining molecular mechanisms, as well as their relevance for the development of diseases in the female reproductive system. Overall, this may be helpful to define accurate risk assessment and management strategies to protect the health of the general and occupational populations exposed to Pd-NPs.

Palladium Nanoparticles: Toxicological Effects and Potential Implications for Occupational Risk Assessment

“…Experiments carried out on animal models are extremely important to primarily define the toxico-kinetic and dynamic- behavior of NPs, as well as to identify possible biological indicators of exposure and early effect. Several organ systems have been reported to be affected by NP exposure, from the immune to the endocrine, as well as the renal systems [ 52 , 53 , 54 , 55 , 62 ]. However, it remains to be elucidated whether early alterations detected in sub-acute, sub-chronic conditions of exposure, i.e., cytokine changes, alteration in hormonal serum concentrations, as well as increase in urinary protein content, may persist in the long term, and their possible role in disease development and manifestation.…”

“…Several biological models, from bacterial strains [ 51 ] to mammalian organisms were reported to be affected by Pd-NP treatment. The immune [ 52 , 53 ], renal [ 54 ] and endocrine systems [ 55 ] were demonstrated as critical targets for the toxic action of Pd-NPs ( Table 2 ). The elemental Pd content in urine, and changes in cytokine serum levels, urinary protein content and hormonal serum concentrations, emerged as possible biomarkers of Pd-NP exposure and early effect, although further studies are necessary to confirm these preliminary results and validate their possible employment in real exposure settings.…”

“…More recently, a first attempt to investigate the endocrine disruptive potential of Pd-NPs was performed by our group of research in an animal model of sexually mature female Wistar rats sub-acutely exposed to NPs via a single tail vein injection [ 55 ]. An abnormal function of the hypothalamic–pituitary–gonadal axis was detected as demonstrated by the reduced serum concentrations of estradiol (E2) and testosterone (T) and the increased level of luteinizing hormone (LH) in treated animals compared to controls, which become significant at the highest exposure dose (12 µg/kg).…”

Sub-chronic palladium nanoparticle effects on the endocrine reproductive system of female Wistar rats: Preliminary data

“…Pd-NP hydrosols were prepared as previously described (Fontana et al, 2015;Iavicoli et al, 2015Iavicoli et al, , 2017Leso et al, 2018b). Briefly, an aqueous palladium nitrate solution (1000 mg Pd/L as Pd(NO 3 ) 2 ) in 0.5 M nitric acid (HNO 3 ) served as a precursor for elemental Pd-NPs.…”

“…Therefore, their widespread use may represent a primary anthropogenic source of nanoscale-Pd into the general living and occupational environments, raising concerns about possible public and industrial health consequences of increasing levels of exposure. Indeed, toxicological data demonstrated that Pd-NPs could exert cytotoxic and immunomodulatory effects in vitro (Alarifi et al, 2017;Boscolo et al, 2010;Dahal et al, 2015;Gurunathan et al, 2015;Iavicoli et al, 2017;Petrarca et al, 2014;Reale et al, 2011;Wilkinson et al, 2011) as well as adverse effects on the renal, endocrine, and immune systems in vivo (Fontana et al, 2015;Iavicoli et al, 2015Iavicoli et al, , 2016Iavicoli et al, , 2018Leso et al, 2018b). Concerning the endocrine system, investigating the possible function of nanomaterials (NMs) as endocrine-disrupting chemicals (EDCs) has become a public health priority (Iavicoli et al, 2013).…”