不同粒径二氧化钛短期摄入对幼年大鼠小肠铁和葡萄糖吸收的影响
Effects of short-term exposure to different sizes of titanium dioxide on iron and glucose absorption in small intestine young rats
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摘要:
目的 研究并比较短期（14 d）经口摄入纳米二氧化钛（titanium dioxide，TiO2）、微米TiO2对幼年大鼠小肠铁和葡萄糖吸收的影响。
方法 将42只幼年（4周龄）雄性Sprague-Dawley（SD）大鼠按体重用随机数字表法分为7组，染毒组每天分别灌胃给予2、10、50 mg/kg（以体重计）的纳米TiO2（平均原始粒径24 nm）或微米TiO2（平均原始粒径120 nm），对照组灌以同体积蒸馏水。连续染毒14 d后，取小肠制作翻转肠囊模型，给予20 mmol/L葡萄糖溶液和20 mmol/L硫酸铁（FeSO4）溶液，观察小肠对铁和葡萄糖的吸收情况。
结果 与对照组相比，经口染毒纳米、微米TiO2 14 d后，大鼠的小肠组织无明显病理改变。各组幼年大鼠小肠对铁及葡萄糖的吸收量均有随时间增加而增加的趋势。纳米TiO2、微米TiO2各剂量组间大鼠小肠对铁及葡萄糖的累积吸收量与吸收速率均呈略高于对照组的趋势，但差异无统计学意义（P > 0.05）。同一时间点，纳米、微米TiO2染毒组的铁与葡萄糖累积吸收量和吸收速率均未表现出剂量-反应关系，各染毒组差异无统计学意义（F铁累积吸收量=0.674，F铁吸收速率=0.674；F葡萄糖累积吸收量=1.332；F葡萄糖吸收速率=1.545；均P > 0.05）。在相同染毒剂量下，纳米TiO2染毒组的大鼠小肠对铁及葡萄糖的吸收量、吸收速率与微米TiO2染毒组相比，差异亦无统计学意义（均P >0.05）。
结论 短期经口摄入纳米、微米TiO2对幼年大鼠小肠铁及葡萄糖的吸收无明显影响，且纳米、微米TiO2的作用无明显差异。
Abstract:Objective To study and compare the effects of short-term oral exposure to titanium dioxide (TiO2) nanoparticles and microparticles on the absorption of iron and glucose in small intestine of young rats.
Methods Forty-two male SD rats (4 weeks old) were randomly divided into seven groups. The exposed rats were orally treated with 2, 10, 50 mg/kg (in terms of body weight) TiO2 nanoparticles or microparticles (average original particle size:24 nm or 120 nm), respectively, once a day for consecutive 14 days, and the control group was administered with distilled water at the same volume. Everted gut sac model was utilized to study the small intestinal absorption of iron and glucose with supplement of 20 mmol/L glucose solution and 20 mmol/L ferrous sulfate (FeSO4) solution.
Results Compared to the control group, the small intestines of rats in both the TiO2 nanoparticle groups and the TiO2 microparticle groups didn't show any obvious pathological changes after the 14-day oral treatment. The cumulative glucose and iron absorption tended to increase with the extension of time in all groups. The rate and amount of iron and glucose absorbed in both TiO2 nanoparticle and microparticle groups were slightly higher than those of the control group, but the differences were not statistically significant (P > 0.05). At the same time point, the rate and amount of iron and glucose cumulative absorption didn't show a doseresponse relationship, and there were no significant differences in the different dose groups (Fcumulative iron absorption=0.674, Frate of iron absorption=0.674; Fcumulative glucose absorption=1.332, Frate of glucose absorption=1.545; Ps > 0.05). Under the same exposure dose, no differences in the rate and amount of iron and glucose absorbed were found between the TiO2 nanoparticle and microparticle groups (Ps >0.05).
Conclusion Short-term oral exposure to TiO2 nanoparticles and microparticles shows no obvious influence on the small intestinal absorption of iron and glucose in young rats, and there is no noticeable difference between TiO2 nanoparticle and microparticle groups.
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