纳米二氧化钛长期暴露对BALB/C裸鼠皮肤的损伤

Effect of nanotitanium dioxide long term exposure on the skin damage in Balb/c nude mice

目的通过在体实验,研究纳米Ti O2的在体透皮行为。方法将16只BALB/c裸鼠随机分成2个饲养组:分别为纳米Ti O2组和空白对照组,每组动物8只,雌雄各半。用Carbopol 940制成浓度为5%的纳米Ti O2凝胶涂抹裸鼠颈背部皮肤,正常对照组涂抹空白基质,60 d后眼眶采取血样并断颈处死全部裸鼠,立即取下背部暴露处全层皮肤(不含皮下脂肪)。并对上述标本进行组织病理学检查、TEM观察、原子吸收光谱(Ti含量)测定,及其他常规毒理学检查。结果 Bulb/c裸鼠整体透皮60 d后,不同粒径纳米Ti O2均不同程度的穿透裸鼠皮肤,进入皮下各组织和脏器中,并引起相应的组织病理学改变,主要表现为组织炎性细胞浸润及灶性坏死,裸鼠暴露皮肤出现褶皱加深、松弛、无光泽等老化现象,光学显微镜下皮肤组织呈现表皮角化过度、表皮变薄及深层细胞萎缩等病理学改变,皮肤组织匀浆样品中羟脯氨酸(HYP)含量、超氧化物歧化酶(SOD)水平显著降低,丙二醛(MDA)含量明显上升。结论纳米Ti O2长期暴露可导致皮肤老化及氧化损伤。

Objective To explore the skin penetration of nano-Ti O2 in vivo. Methods Bulb / c nude mice were divided into two groups： control group,nano-Ti O2 group,respectively; Each group has 8 mice; Carbopol 940 with a concentration of 5% of nano-Ti O2 gel was used to coate on the back of the neck skin of nude mice and matrix blank control. After 60 days,blood samples were taken after the mice were sacrificed and immediately remove the exposed whole layer skin. Results This study obtained a more clearly presentation on its tissue distribution and potential toxicities after skin exposure for 60 days. The most important pathological changes were inflammatory infiltrates and foci of necrosis. The skin of Bulb / c nude mice showed more wrinkles,loose and lacking brightness with the significant changes in SOD and MDA levels,which suggested that these lesions were likely to be mediated with oxidative stress by the deposited nano-Ti O2. Accordingly,the content of collagen expressed as HYP was also reduced in mice skin. Conclusion It indicates that topically applied nano-Ti O2 on skin with a prolonged period could lead to skin aging and oxidative damage.