Biomaterial Database

Induction of sister chromatid exchanges and micronuclei by titanium dioxide in Chinese hamster ovary-K1 cells. 1998

P J Lu, and I C Ho, and T C Lee

Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan.

Titanium dioxide (TiO2) has color properties of extreme whiteness and brightness, is relatively inexpensive, and is extensively used as a white pigment in a variety of materials. TiO2, an effective blocker of ultraviolet light, is frequently added to sunscreens and cosmetic creams. However, the genotoxicity of TiO2 remains to be controversial. In this report, we have demonstrated that TiO2 can be transported into Chinese hamster ovary-K1 (CHO-K1) cells. The effects of TiO2 on induction of sister chromatid exchanges (SCE) and micronuclei (MN) were then studied in these cells. The SCE frequency in CHO-K1 cells treated with TiO2 at a nonlethal dose range (0 to 5 microM) for 24 h was significantly and dose-dependently increased. By the conventional MN assay, TiO2 at the dose ranged from 0 to 20 microM slightly increased the MN frequency in CHO-K1 cells. However, in the cytokinesis-block MN assay, the number of MN per 1000 binucleated cells was significantly and dose-dependently enhanced in CHO-K1 cells treated TiO2 at the same dose range for 24 h. These results suggest that TiO2 is a potential genotoxic agent.

UI	MeSH Term	Description	Entries
D009153	Mutagens	Chemical agents that increase the rate of genetic mutation by interfering with the function of nucleic acids. A clastogen is a specific mutagen that causes breaks in chromosomes.	Clastogen,Clastogens,Genotoxin,Genotoxins,Mutagen
D002470	Cell Survival	The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability.	Cell Viability,Cell Viabilities,Survival, Cell,Viabilities, Cell,Viability, Cell
D006224	Cricetinae	A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.	Cricetus,Hamsters,Hamster
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012854	Sister Chromatid Exchange	An exchange of segments between the sister chromatids of a chromosome, either between the sister chromatids of a meiotic tetrad or between the sister chromatids of a duplicated somatic chromosome. Its frequency is increased by ultraviolet and ionizing radiation and other mutagenic agents and is particularly high in BLOOM SYNDROME.	Chromatid Exchange, Sister,Chromatid Exchanges, Sister,Exchange, Sister Chromatid,Exchanges, Sister Chromatid,Sister Chromatid Exchanges
D013473	Sunscreening Agents	Chemical or physical agents that protect the skin from sunburn and erythema by absorbing or blocking ultraviolet radiation.	Sunscreen,Sunscreens,Agents, Sunscreening
D014025	Titanium	A dark-gray, metallic element of widespread distribution but occurring in small amounts with atomic number, 22, atomic weight, 47.867 and symbol, Ti; specific gravity, 4.5; used for fixation of fractures.
D016466	CHO Cells	CELL LINE derived from the ovary of the Chinese hamster, Cricetulus griseus (CRICETULUS). The species is a favorite for cytogenetic studies because of its small chromosome number. The cell line has provided model systems for the study of genetic alterations in cultured mammalian cells.	CHO Cell,Cell, CHO,Cells, CHO
D048629	Micronuclei, Chromosome-Defective	Defective nuclei produced during the TELOPHASE of MITOSIS or MEIOSIS by lagging CHROMOSOMES or chromosome fragments derived from spontaneous or experimentally induced chromosomal structural changes.	Chromosome-Defective Micronuclei,Genotoxicant-Induced Micronuclei,Micronuclei, Genotoxicant-Induced,Micronucleus, Chromosome-Defective,Chromosome Defective Micronuclei,Chromosome-Defective Micronucleus,Genotoxicant Induced Micronuclei,Genotoxicant-Induced Micronucleus,Micronuclei, Chromosome Defective,Micronuclei, Genotoxicant Induced,Micronucleus, Chromosome Defective,Micronucleus, Genotoxicant-Induced