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Toxicological information

Toxicity to reproduction: other studies

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Administrative data

Endpoint:
toxicity to reproduction: other studies
Type of information:
experimental study
Adequacy of study:
disregarded due to major methodological deficiencies
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The publication is not relevant for human health risk assessment due to irrelevant route of test item application. - TiO2 powder size was confirmed by FE-SEM (results in graphic form). - number of animals examined was not clear. - frequency of treatment is not guideline conform. - only one dose level - Test item insufficiently characterised.

Data source

Reference
Reference Type:
publication
Title:
Nanoparticles transferred from pregnant mice to their offspring can damage the genital and cranial nerve systems.
Author:
Takeda, K. et al.
Year:
2009
Bibliographic source:
J. Health Sci. 55: 95-102.

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Pregnant mice received subcutaneous injections of 100 µL of 1 mg/mL TiO2 particles in saline plus 0.05% Tween 80 at 3, 7, 10, and 14 days postcoitum. Control mice were treated on the same schedule with 0.05% Tween 80. Male offspring were weighed and killed under anaesthesia at 4 days or 6 weeks of age. The following examinations were carried out with the offsprings: body weights, organ weights, determination of number of sperm nuclei, determination of sperm motility and sperm morphology, FE-SEM/EDS analysis of testis and brain and immunohistochemical staining of olfactory bulb and cerebral cortex.
GLP compliance:
not specified
Type of method:
in vivo

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: nanoform
Details on test material:
- Name of test material (as cited in study report): TiO2 particles
- Particle size: 25 - 70 nm (confirmed by FE-SEM)
- Surface area 20 - 25 m²/g
- Physical state: anatase form
- Analytical purity: 99.9%

Test animals

Species:
mouse
Strain:
other: Slc:ICR
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Japan SLC Inc., Shizuoka, Japan

Administration / exposure

Route of administration:
subcutaneous
Vehicle:
other: saline plus 0.05% Tween 80
Details on exposure:
Pregnant mice received subcutaneous injections of 100 µL of 1 mg/mL TiO2 particles in saline plus 0.05% Tween 80 at 3, 7, 10, and 14 days postcoitum. Control mice were treated on the same schedule with 0.05% Tween 80.
Analytical verification of doses or concentrations:
not specified
Details on analytical verification of doses or concentrations:
no data
Duration of treatment / exposure:
3, 7, 10, and 14 days postcoitum
Frequency of treatment:
not stated
Doses / concentrations
Remarks:
Doses / Concentrations:
100 µL of 1 mg/mL TiO2 particles
Basis:
other: injected subcutanouesly
No. of animals per sex per dose:
6 mice
Control animals:
yes
Details on study design:
Male offspring were weighed and killed under anaesthesia at 4 days or 6 weeks of age. In order to determine the genital toxicity of TiO2 particles, body and reproduction weights were measured.
The weight of the testis, epididymis, and seminal vesicle (including prostate, seminal vesicle, and coagulating gland) bilaterally and brain were measured for each animal, and relative weights (weight of the organ/body weight) were calculated in 6-week-old offspring. Testes were homogenized and the number of sperm nuclei in each suspension was determined by hemocytometer. Sperm samples were collected from the cauda epididymis, and sperm motility and morphology were evaluated under phase contrast microscopy. Testes of 6-week-old mice were homogenized, and daily sperm production was examined. Testes were also fixed and stained for examination by light and electron microscopy.
The testis or brain tissue were analysed for the presence of TiO2 particles by FE-SEM/EDS. Furthermore, tissue samples of olfactory bulb and cerebral cortex (frontal and temporal lobes) of 6 weeks old mice were examined by TEM and FE-SEM/EDS.
Statistics:
Data were analysed by Mann-Whitmey U test, and differences were considered significant at p < 0.05.

Results and discussion

Effect levels

Basis for effect level:
other: According to the authors, nano-sized titanium dioxide administered subcutaneously to pregnant mice is transferred to the offspring and affects the genital and cranial nerve system of the male offspring.
Remarks on result:
not measured/tested
Remarks:
Effect level not specified (migrated information)

Observed effects

- TiO2-exposed group had significantly lower body weight (88% relative to control) and significantly higher weight of epidermis per body weight (117% relative to control). There were no significant changes in the weight of other reproductive organs.
- aggregates of TiO2 nanoparticles (100 - 200 nm) were detected in Leydig cells, Sertoli cells, and spermatids in the testis at both 4 days and 6 weeks of age.
- testicular morphology in TiO2-exposed mice was abnormal compared to that in control mice. In exposed mice, some seminiferous tubules appeared disorganized and disrupted. There were fewer mature sperm in the tubule lumen. The damaged tubules were scattered randomly throughout the testis. These effects were dependent on the dose of TiO2 and were significantly higher in TiO2 exposed mice than in control mice. Daily sperm production per gram of testis , epididymal sperm motility and the number of Sertoli cells were significantly lower in mice exposed to TiO2 than in control mice. Sperm morphology did not differ significantly.
- nanosized TiO2 particles were detected in cells in brains of 6-week old mice exposed prenatally to TiO2.
- numerous cells positive for caspase-3, a common enzymatic marker of apoptosis, were observed under light microscope in the olfactory bulb of 6-week-old mice exposed prenatally to TiO2, and the number of caspase-3-positive mitral cells was significantly higher in exposed mice than in control mice (no positive cells).
- electron microscopic observations of olfactory bulb revealed that a subset of cells contained cresent-shaped spaces, which are specific features of apoptosis (Ihara et al. (1998)*). Apoptotic granular perithelial cells , which are scavenger cells that surround vessels in the brain, contained unidentified particulate matter. Occlusion of small vessels and perivascular oedema were observed in the prenatally TiO2-exposed mice.

*Reference:
- Ihara, T., Yamamoto, T., Sugamata, M., Okumura, H. and Ueno, Y. (1998) the processof ultrastructural changes from nuclei to apoptotic body. virchows Arch., 433, 443 - 447.

Applicant's summary and conclusion

Conclusions:
According to the authors, nano-sized titanium dioxide administered subcutaneously to pregnant mice is transferred to the offspring and affects the genital and cranial nerve system of the male offspring. They mentioned that nanoparticles identified as TiO2 by energy-dispersive X-ray spectroscopy were found in testis and brain of exposed 6-week-old male mice. Furthermore, they stated that in the offspring of TiO2-injected mice, various functional and pathologic disorders, such as reduced daily sperm production and numerous caspase-3 (a biomarker of apoptosis) positive cells in the olfactory bulb of the brain were observed.