不同粒径纳米二氧化钛对大鼠氧化应激的影响

Effects of Different Sized Titanium Dioxide Nanoparticles on Oxidative Stress in Rats

目的探讨不同粒径的纳米二氧化钛(TiO2)对大鼠氧化应激的影响。方法将50只SD大鼠随机分为空白对照组、溶剂对照组以及200、25和15 nm 3种粒径的TiO2染毒组。每天以40 mg TiO2进行皮肤染毒,连续染毒7 d,股动脉取血,检测血清中丙二醛(MDA)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和8-羟基脱氧鸟苷(8-OHdG)等指标。结果200、25和15 nm TiO2染毒组雌性大鼠血清SOD活性分别为(22.73±5.10)、(18.13±6.02)和(12.87±4.23)U/ml,空白对照和溶剂对照组分别为(28.77±3.05)和(24.43±5.92)U/ml,25 nm TiO2染毒组SOD活性较空白对照组下降(P<0.05),15 nm TiO2染毒组较空白对照、溶剂对照和200 nm TiO2染毒组均下降(P<0.05),而雄性大鼠各组间SOD活性无明显变化(P>0.05);200、25和15 nm TiO2染毒组雌性大鼠血清8-OHdG分别为(7.91±0.66)、(8.02±0.93)和(8.93±0.56)ng/ml,空白对照和溶剂对照组分别为(7.24±0.69)和(7.66±0.69)ng/ml,15 nm TiO2染毒组8-OHdG含量较空白对照、溶剂对照组均升高(P<0.05),而雄性大鼠各组间8-OHdG无明显变化(P>0.05);CAT活性、MDA含量各组间差异无统计学意义(P>0.05)。结论 25 nm和15 nm级TiO2皮肤染毒可引起大鼠氧化应激反应,该反应与TiO2的粒径大小有关,并具有性别差异。

Objective To investigate the oxidative stress effects of titanium dioxide nanoparticles （nano -TiO2 ） of different size in rats. Methods 50 SD rats were randomly divided into five groups,including blank control group, solvent group and other three groups with different sized nano - TiO2 exposure. The rats were exposed in nano - TiO2 through skin with the dose of 40 mg/d. The levels of MDA and 8 - OHdG, the activities of SOD and CAT in the serum were measured. Results The activity of SOD in the serum of female rat with 200 nm, 25 nm and 15 nm TiO2 exposure were（22. 73± 5. 10）, （ 18. 13 ± 6. 02） and（ 12. 87 ± 4.23 ） U/ml, respectively, while those in the blank control group and solvent group were （28. 77 ±3.05） and （24. 43 ±5.92） U/ml. The activity of SOD in the female rat serum decreased significantly in the group with 25 nm TiO2 exposure when compared with the blank control group （ P 〈 0. 05 ）. Compared with the blank control group , solvent group or the group with 200 nm TiO2 exposure , the activities of SOD in serum of the female rat decreased significantly in the group with 15 nm TiO2 exposure respectively（ P 〈 0. 05）. However, there were no statistical differences in the activity of SOD among five male groups（ P 〉 0. 05）. The levels of 8 -OHdG in the female rat serum with 200 nm,25 nm and 15 nm TiO2 exposure were（7. 91 s 0. 66）, （8. 02 s 0. 93 ） and（ 8. 93 s 0. 56） ng/ml , respectively, while those in the blank control group and solvent group were （7.24 ±0. 69） and （7. 66±0. 69） ng/ml. Compared with the blank control group or solvent group, the level of 8 - OHdG in the female rat serum increased significantly in the group with 15 nm TiO2 exposure（ P 〈 0. 05 ）. However, there were no statistical differences in the levels of g - OHdG among five male groups（ P 〉 0. 05 ）. The male and female rats did not show any significant changes in the activities of CAT or the levels of MDA after 200 nm ,25 nm and 15 nm TiO2 exposure, respectively（ P 〉 0. 05 ）. Conclusion The skin exposure to 25 nm and 15 nm TiO2 could induce the oxidative stress in rats which is related to the size of the TiO2 and the gender of the rats.