Subacute oral toxicity investigation of selenium nanoparticles and selenite in rats

Abstract

Selenium (Se) nanoparticles have been proposed as food supplements. However, the particle formulation may exert unexpected toxicity. The aim was therefore to compare toxicity of low doses of Se nanoparticles and the dissolved, ionized Se species selenite. Female rats were dosed orally for 28 d with either: 0.05, 0.5, or 4 mg Se/kg body weight (bw)/day as 20 nm Se nanoparticles or 0.05 or 0.5 mg Se/kg bw/day as sodium selenite. Male rats were dosed 4 mg Se/kg bw/day as Se nanoparticles. Body weight and clinical appearance were recorded throughout the experiment. At necropsy, blood samples were taken for hematological and clinical chemistry analyses; organ weights were recorded. At the high-dose of Se nanoparticles, overt toxicity occurred and the female animals had to be euthanized prematurely, whereas the male animals were reduced in dose. At all doses of Se nanoparticles and at 0.5 mg Se/kg bw/day as selenite, a lower body weight gain as compared to vehicle occurred. Relative liver weight was increased for both Se formulations at 0.5 mg Se/kg bw/day. Creatinine clearance and urinary pH were affected in some Se dosed groups. There were no effects among dosed groups on brain neurotransmitters or on hematological parameters compared with controls. There were no histological changes in the livers of animals exposed to Se nanoparticles or to selenite. Based on effects on body weight and liver weight, selenium nanoparticles and ionic Se exerted similar toxicity. This suggests that a nanoparticle-specific toxicity of Se did not occur.

Effects of Sub-Lethal Doses of Selenium Nanoparticles on the Health Status of Rats

“…Our results are supported by Hey et al, who presented damage of selected tissues in supranutritional and nonlethal levels from 0.2 to 8 mg Se/kg [51]. Contrary to these results, no histological changes in the livers of rats exposed to SeNPs or selenite (0.05, 0.5 and 4mg Se/kg) have been observed in recently published results by Hadrup et al [12].…”

“…Thus, the nanotoxicity of Se is still under careful consideration. The toxicologic impact of SeNPs has been studied for several kinds of SeNPs in tissue cells [10], rats, mice [11,12], aquaculture [13] or chickens [14]. The main limitation of performed studies is variability in the used type of SeNPs and non-uniform dosing.…”

Effects of Cerium Oxide Nanoparticles on Biochemical Parameters and Histopathological Changes in Lead-Intoxicated Rats

“…The results of He et al showed that CeNPs -at super nutritional levelshad no obvious toxic effects in rats (18). These results were in agreement with those of Hadrup et al (19). The difference in biological reports of CeNPs could be due to the difference in the dose, duration of study, and method of administrating CeNPs.…”

Understanding the Redox Biology of Selenium in the Search of Targeted Cancer Therapies

“…This specific model showed relatively high cytotoxicity in HepG2 and multi-drug resistance HepG2 cell lines. In contrast, there was no change in hematological values, nor was liver toxicity observed in female rats exposed to a relatively high dose of 5 mg kg -1 Se nanoparticles (20 nm) [174].…”