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Numano T.,Nagoya City University | Numano T.,DIMS Institute of Medical Science | Xu J.,Nagoya City University | Futakuchi M.,Nagoya City University | And 7 more authors.
Asian Pacific Journal of Cancer Prevention | Year: 2014

Two types of nanosized titanium dioxide, anatase (anTiO2) and rutile (rnTiO2), are widely used in industry, commercial products and biosystems. TiO2 has been evaluated as a Group 2B carcinogen. Previous reports indicated that anTiO2 is less toxic than rnTiO2, however, under ultraviolet irradiation anTiO2 is more toxic than rnTiO2 in vitro because of differences in their crystal structures. In the present study, we compared the in vivo and in vitro toxic effects induced by anTiO2 and rnTiO2. Female SD rats were treated with 500 mg/ml of anTiO2 or rnTiO2 suspensions by intra-pulmonary spraying 8 times over a two week period. In the lung, treatment with anTiO2 or rnTiO2 increased alveolar macrophage numbers and levels of 8-hydroxydeoxyguanosine (8-OHdG); these increases tended to be lower in the anTiO2 treated group compared to the rnTiO2 treated group. Expression of MIP1α mRNA and protein in lung tissues treated with anTiO2 and rnTiO2 was also significantly up-regulated, with MIP1α mRNA and protein expression significantly lower in the anTiO2 group than in the rnTiO2 group. In cell culture of primary alveolar macrophages (PAM) treated with anTiO2 and rnTiO2, expression of MIP1α mRNA in the PAM and protein in the culture media was significantly higher than in control cultures. Similarly to the in vivo results, MIP1α mRNA and protein expression was significantly lower in the anTiO2 treated cultures compared to the rnTiO2 treated cultures. Furthermore, conditioned cell culture media from PAM cultures treated with anTiO2 had less effect on A549 cell proliferation compared to conditioned media from cultures treated with rnTiO2. However, no significant difference was found in the toxicological effects on cell viability of ultra violet irradiated anTiO2 and rnTiO2. In conclusion, our results indicate that anTiO2 is less potent in induction of alveolar macrophage infiltration, 8-OHdG and MIP1α expression in the lung, and growth stimulation of A549 cells in vitro than rnTiO2.

Shirai T.,Nagoya City University | Imai N.,DIMS Institute of Medical Science | Wang J.,Nagoya Institute of Technology | Takahashi S.,Nagoya City University | And 6 more authors.
Bioelectromagnetics | Year: 2014

The present experimental study was carried out with rats to evaluate the effects of whole body exposure to 2.14 GHz band code division multiple access (W-CDMA) signals for 20 h a day, over three generations. The average specific absorption rate (SAR, in unit of W/kg) for dams was designed at three levels: high (<0.24 W/kg), low (<0.08 W/kg), and 0 (sham exposure). Pregnant mothers (4 rats/group) were exposed from gestational day (GD) 7 to weaning and then their offspring (F1 generation, 4 males and 4 females/dam, respectively) were continuously exposed until 6 weeks of age. The F1 females were mated with F1 males at 11 weeks old, and then starting from GD 7, they were exposed continuously to the electromagnetic field (EMF; one half of the F1 offspring was used for mating, that is, two of each sex per dam and 8 males and 8 females/group, except for all offspring for the functional development tests). This protocol was repeated in the same manner on pregnant F2 females and F3 pups; the latter were killed at 10 weeks of age. No abnormalities were observed in the mother rats (F0, F1, and F2) and in the offspring (F1, F2, and F3) in any biological parameters, including neurobehavioral function. Thus, it was concluded that under the experimental conditions applied, multigenerational whole body exposure to 2.14 GHz W-CDMA signals for 20 h/day did not cause any adverse effects on the F1, F2, and F3 offspring. Bioelectromagnetics 35:497-511, 2014. © 2014 Wiley Periodicals, Inc.

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