Genetic effects of chemically and biosynthesized titanium dioxide nanoparticles in vitro and in vivo of female rats and their fetuses

Abstract

With the increase in nanoparticles (NPs) products on the market, the possibility of animal and human exposure to these materials will increase. The smaller size of NPs facilitates their entrance through placental barriers and allows them to accumulate in embryonic tissue, where they can then be a source of different developmental malformations. Several toxicity studies with chemically synthesized titanium dioxide NPs (CTiO₂ NPs) have been recently carried out; although there is insufficient data on exposure to biosynthesized titanium dioxide NPs (BTiO₂ NPs) during pregnancy, the study aimed to evaluate the ability of an eco-friendly biosynthesis technique using garlic extract against maternal and fetal genotoxicities, which could result from repeated exposure to TiO₂ NPs during gestation days (GD) 6-19. A total of fifty pregnant rats were divided into five groups (n = 10) and gavaged CTiO₂ NPs and BTiO₂ NPs at 100 and 300 mg/kg/day concentrations. Pregnant rats on GD 20 were anesthetized, uterine horns were removed, and then embryotoxicity was performed. The kidneys of the mothers and fetuses in each group were collected and then maintained in a frozen condition. Our results showed that garlic extract can be used as a reducing agent for the formation of TiO₂ NPs. Moreover, BTiO₂ NPs showed less toxic potential than CTiO₂ NPs in HepG₂ cells. Both chemically and biosynthesized TiO₂ NP-induced genetic variation in the 16S rRNA sequences of mother groups compared to the control group. In conclusion, the genetic effects of the 16S rRNA sequence induced by chemically synthesized TiO₂ NPs were greater than those of biosynthesized TiO₂ NPs. However, there were no differences between the control group and the embryo-treated groups with chemically and biologically synthesized TiO₂ NPs.

Keywords: 16S rRNA; biosynthesized; developmental toxicity; particle characterization; titanium dioxide.

Figure 1

XRD patterns of CTiO₂ and BTiO₂ NPs.

Figure 2

UV spectra of BTiO₂ and CTiO₂ NPs.

Figure 3

Optical band gap of CTiO₂ and BTiO₂ NPs.

Figure 4

Raman spectra of CTiO₂ and BTiO₂ NPs.

Figure 5

FTIR spectra of garlic extract and BTiO₂ and CTiO₂ NPs.

Figure 6

HRTEM images and particle size distribution of BTiO₂ and CTiO₂ NPs.

Figure 7

Microscopic images of HepG₂ cells after 24 h of exposure to BTiO₂ and CTiO₂ NPs at two concentrations (0.5 and 8 mM).

Figure 8

Cell viability of HepG₂ cells after 24 h of exposure to BTiO₂ and CTiO₂ NPs at two concentrations (0.5 and 8 mM).

Figure 9

Alignment of 16S rRNA partial sequences in mother-five groups. Dots refer to identical nucleotides, and A, T, C, and G refer to different nucleotides.

Figure 10

(A–E) Transverse sections stained with H&E from fetal kidney of control (untreated) and experimental (treated) groups: (A) Light section of control showing intact nephritic tubules (arrow) and glomerulus (star). (B) Light section of C100–TiO₂ NPs showing separation of epithelium-lining tubules from the basement membrane (arrow), besides mononuclear infiltrate (star). (C) Light section of C300–TiO₂ NPs showing necrosis of the renal tubules replaced by inflammatory cells (arrow) as well as desquamated epithelial cells (star). (D) Light section of B100–TiO₂ NPs showing apparently healthy renal parenchyma (arrow). (E) Light section of B300–TiO₂ NPs showing healthy glomeruli (arrow) and mild congestion of the renal blood vessels (star). Scale bar = 200 μm.