Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: KEGG:D01931 (TiO2)
 11,320 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sunscreens are known to-protect against sunlight-induced erythema and sunburn, but their efficiency at protecting against skin cancer is still a matter of debate. Specifically, the capacity of physical sunscreens to prevent or reduce tissue and DNA damage has not been thoroughly investigated. Our objective was to assess the ability of a broad-spectrum sunscreen containing TiO2 to protect human skin against tissue and DNA damage following ultraviolet radiation. For this purpose, engineered human skin (EHS) was generated and either treated or not treated with an SPF 28 physical sunscreen and exposed to increasing doses of simulated sunlight (SSL). Immediately after irradiation, histological, immunohistochemical and molecular analyses were performed. Cyclobutane pyrimidine dimers and pyrimidine (6-4) pyrimidone photoproducts were measured by radioimmunoassay, photooxidative lesions were measured by neutral glyoxal gel electrophoresis. The unprotected irradiated EHS showed significant epidermal disorganization accompanied by a complete absence of laminin deposition. The physical sunscreen prevented SSL-induced epidermal damage at low doses and allowed laminin deposition at almost all SSL doses tested. The frequencies of all 3 types of molecular photodamage were significantly reduced in the sunscreen-protected tissues. In conclusion, although, the level of protection against erythema offered by this sunscreen does not correlate with the level of protection against DNA damage, these results strongly suggest that an SPF 28 physical sunscreen significantly protected human skin against solar UV radiation. Thus, tissue and DNA damage may provide excellent quantitative endpoints for assessing the photoprotective efficiency of sunscreens.
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PMID:A physical sunscreen protects engineered human skin against artificial solar ultraviolet radiation-induced tissue and DNA damage. 1265 57

Recently there has been a strong demand to protect human skin against negative effects of the UV solar light. This problem is interesting due to the increased frequency of human diseases caused by such radiation. We aim to evaluate how the optical properties of the horny layer of skin can be effectively changed by imbedding TiO2 fine particles to achieve the maximal attenuation of the UV solar radiation. In-depth distribution of TiO2 particles embedded into the skin by multiple administration of sunscreens is determined experimentally using the tape-stripping technique. A computer code implementing the Monte Carlo method is developed to simulate photon migration within the 20-microm-thick horny layer filled with nanosized TiO2 spheres, 25 to 200 nm in diameter. Dependencies of the UV radiation of two wavelengths (310 and 400 nm) absorbed by and totally reflected from, as well as transmitted through the horny layer on the size of TiO2 particles are obtained and analyzed. The most attenuating particles are found to be 62 and 122 nm in diameter for 310- and 400-nm light, respectively. The former could be suggested as the main fraction to be used in sunscreens to prevent erythema.
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PMID:Effect of size of TiO2 nanoparticles embedded into stratum corneum on ultraviolet-A and ultraviolet-B sun-blocking properties of the skin. 1640 2