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目的研究纳米二氧化钛对大鼠体内氧化应激水平及大鼠海马组织结构的影响。方法将32只健康SPF级雄性Wistar大鼠随机分为4组,分别为对照(蒸馏水)组和低(250 mg/kg)、中(500 mg/kg)、高(1 000 mg/kg)剂量纳米二氧化钛组,每组8只。采用灌胃方式进行染毒,每天1次,连续染毒14 d。分别在染毒第3、7、14天测定大鼠血浆中总超氧化物歧化酶(T-SOD)活力、谷胱甘肽过氧化物酶(GSH-Px)活力、总抗氧化能力(T-AOC)及丙二醛(MDA)含量;实验结束后,观察海马组织结构的变化。结果与对照组比较,第3、7、14天高剂量纳米二氧化钛组血浆中T-SOD、GSH-Px活力和T-AOC均明显降低,MDA含量均明显升高;中剂量纳米二氧化钛组T-SOD活力在第3、14天明显降低,GSH-Px活力在第14天明显降低,T-AOC在第3天明显降低,MDA含量在第7、14天明显升高,差异均有统计学意义(P<0.05);而低剂量纳米二氧化钛组以上4个指标均无显著改变。在各剂量纳米二氧化钛染毒组内,仅低、中剂量组第14天T-SOD活力显著低于第3天,差异均有统计学意义(P<0.05)。各染毒组海马区神经细胞出现不同程度的病理改变,如染色质溶解、核固缩、细胞密度降低等现象,中、高剂量组可见神经细胞坏死形成的空泡状区域。结论本实验条件下,纳米二氧化钛染毒可引起体内氧化应激反应增强,并可导致大鼠海马组织结构损伤。
Objective To study the effects of nano-TiO2 on oxidative stress and the histopathology of hippocampus in rats. Methods Thirty-two healthy Wistar rats were randomly divided into 4 groups: control (distilled water) group and low (250 mg / kg) Nano titanium dioxide group, each group of eight. Gavage by way of exposure, 1 times a day, continuous exposure to 14 d. The activities of total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px) and total antioxidant capacity (T -AOC) and malondialdehyde (MDA). After the experiment, the changes of hippocampal tissue structure were observed. Results Compared with the control group, the activities of T-SOD, GSH-Px and T-AOC were significantly decreased and the contents of MDA were significantly increased on the 3rd, 7th and 14th day in the high-dose nano-TiO 2 group. The activity of SOD decreased significantly on the 3rd and 14th days, the activity of GSH-Px decreased significantly on the 14th day, the T-AOC decreased significantly on the 3rd day, the MDA content increased significantly on the 7th and the 14th day, the differences were statistically significant (P <0.05). However, there was no significant change in the above four indexes of low-dose nano-titanium dioxide group. In each dose of nano-titanium dioxide exposure group, the activity of T-SOD in the low and middle dose groups on the 14th day was significantly lower than that on the 3rd day (P <0.05). The hippocampal neurons exposed to various degrees of pathological changes, such as chromatin dissolution, nuclear pyknosis, cell density and other phenomena, medium and high dose group visible neurovascular necrosis of the vacuolar area. Conclusion Under the experimental conditions, exposure to nano-sized titanium dioxide can result in increased oxidative stress in vivo and damage to hippocampal tissue structure in rats.