饮水型砷暴露对家兔皮肤抗氧化水平影响研究

Effects of arsenic exposure through drinking water on antioxidant capacity of rabbit skin tissue

目的通过分析相关抗氧化酶水平并结合尿形态砷变化水平探讨砷对家兔皮肤抗氧化水平的影响。方法将30只成年健康清洁级雄性新西兰家兔随机分为5组,分别为0(对照)、0.075(1/100 LD50)、0.15(1/50 LD50)、0.375(1/20 LD50)、0.75(1/10 LD50)mg/kg,每组6只。采用自由饮水方式进行染毒,连续12周。检测家兔皮肤组织中8-羟基脱氧鸟苷(8-OHd G)、过氧化氢酶(CAT)、髓过氧化物酶(MPO)含量及血红素氧合酶1(HO-1)活力;同时,检测家兔尿中As(Ⅲ)、As(Ⅴ)、一甲基胂酸(MMA)和二甲基胂酸(DMA)含量,并分析砷代谢情况[一甲基化率(PMI)、二甲基化率(SMI)]。结果与对照组相比,0.150、0.375、0.750 mg/kg亚砷酸钠染毒组家兔皮肤组织内CAT和HO-1活力均较低,而0.750mg/kg亚砷酸钠染毒组家兔皮肤组织内8-OHd G含量较高,差异有统计学意义(P<0.05);各剂量亚砷酸钠染毒组家兔皮肤组织内MPO活力均无明显变化。与对照组相比,0.750 mg/kg亚砷酸钠染毒组家兔尿中总砷、As(Ⅲ)、DMA的含量和0.375、0.750 mg/kg亚砷酸钠染毒组家兔尿中MMA含量及各剂量亚砷酸钠染毒组PMI值以及0.150、0.375、0.750 mg/kg亚砷酸钠染毒组SMI值均较高,差异有统计学意义(P<0.05);而各剂量亚砷酸钠染毒组家兔尿中As(Ⅴ)的含量均无明显变化。结论砷暴露可能通过促进家兔体内砷代谢产物MMA含量以及PMI进而抑制相关抗氧化酶,从而降低抗氧化水平,导致机体氧化损伤。

Objective To discuss the effects of arsenic on antioxidant capacity of rabbit skin tissue by analyzing the contents and activities of antioxidant enzymes and the contents of urine arsenic metabolites. Methods A total of 30 male clean grade New Zealand rabbits were randomly divided into five groups,six in each, treated with sodium arsenite at the doses of 0（control group）,0.075（1/100 LD50）,0.15（1/50 LD50）,0.375（1/20 LD50） and 0.75 mg/kg（1/10 LD50） respectively. The treatment was conducted through drinking water for consecutive 12 weeks. The levels of CAT,MPO,8-OHd G,the activity of HO-1 in rabbit skin tissue and the content of arsenic metabolites in urine including i As（Ⅲ）,i As（Ⅴ）,MMA,DMA were determined, and the arsenic metabolic situation（PMI,SMI） was analyzed. Results Compared with the control group,the level of CAT and the activity of HO-1 were significantly lower in 0.150,0.375 and 0.750 mg/kg sodium arsenite exposure groups（P 〈0.05）,the content of 8-OHd G was significantly higher in 0.750 mg/kg exposure group in rabbit skin tissue（P 〈0.05）. No significant changes were seen in MPO. Compared with the control group,the contents of TAs, As（ Ⅲ）, DMA in 0.750 mg/kg arsenite exposure group and the contents of MMA in 0.375, 0.750 mg/kg arsenite exposure groups in urine, PMI values in each arsenite exposure groups and the index of SMI in 0.150,0.375 and 0.750 mg/kg arsenite exposure groups were significantly higher（P〈0.05）. Conclusion Arsenic exposure may inhibit antioxidant enzymes to reduce rabbit skin antioxidant capacity and cause oxidative damage through the impact on the content of arsenic metabolites MMA and the PMI values.