莱菔硫烷对汞致大鼠肝脏氧化应激的拮抗作用研究

Protective effects of sulforaphane against mercury-induced liver oxidative stress in rats

目的探讨莱菔硫烷(sulforaphane,SFN)对汞所致肝脏氧化应激的拮抗作用。方法实验用Wistar大鼠60只,按体重随机分成6组:对照组,DMSO对照组,低、中、高剂量染汞组、SFN预处理组。对照组和染汞组皮下注射生理盐水,DMSO对照组皮下注射DMSO,SFN预处理组皮下注射2 mg/kg SFN;2 h后,对照组及DMSO对照组腹腔注射生理盐水,低、中、高剂量染汞组分别腹腔注射0.6、1.2、2.4 mg/kg Hg Cl2,SFN预处理组腹腔注射2.4 mg/kg Hg Cl2。注射容量为5 ml/kg。连续预处理与染毒3 d。于最后一次染汞24 h后,每组取6只大鼠,麻醉后处死,冰浴下切取肝组织,测定肝Hg含量、还原型谷胱甘肽(GSH)含量、超氧化物歧化酶(SOD)及谷胱甘肽过氧化物酶(GPx)活力及丙二醛(MDA)含量。每组其余4只大鼠,制备肝脏单细胞悬液,测定肝细胞活性氧簇(ROS)及早期细胞凋亡率。结果与对照组比较,随染汞各组染Hg剂量的升高,肝组织Hg、GSH、MDA含量、肝细胞ROS水平及早期细胞凋亡率逐渐升高,SOD及GPx活力逐渐降低,呈现剂量-效应关系(P<0.01)。2.4 mg/kg Hg Cl2组肝组织Hg、GSH、MDA含量、肝细胞ROS水平及早期细胞凋亡率显著升高,SOD及GPx活力显著降低,差异有统计学意义(P<0.05或P<0.01)。SFN预处理组肝组织Hg含量与2.4 mg/kg Hg Cl2组相比未见明显差异(P>0.05),GSH、MDA含量、ROS水平及早期细胞凋亡率显著下降,SOD及GPx活力显著升高,差异有统计学意义(P<0.05或P<0.01)。结论 SFN对汞所致肝脏氧化应激具有一定程度的拮抗作用。

Objective To explore the protective effects of sulforaphane（SFN） against mercury { Hg）-induced liver oxidative stress in rats. Methods Sixty Wistar rats were randomly divided into six groups, including the control group, DMSO control group, low, median and high doses of Hg treatment groups, and SFN pre-treatment group. The rats in the control group and Hg treatment groups were subcutaneously （ s.c. ） injected with saline. The rats in the DMSO control group were s.c. injected with DM- SO. The rats in the SFN pre-treatment group were s.c. injected with 2 mg/kg SFN dissolved in DMSO. Two hours later, the rats in the control group and DMSO control group were intraperitoneally（ i.p. ） injected with saline. The rats in the low, median and high doses of Hg treatment groups were respectively i.p. injected with 0.6, 1.2 and 2.4 mg/kg mercuric chloride （HgCl2） dissolved in saline , while the rats in the SFN pre-treatment group were i.p. injected with 2.4mg/kg HgCl2. The injection volume was 5ml/kg. SFN pre-treatment or HgCl2 exposure was given every day for up to 3 days. Twenty four hours after the last injection, six rats from each group were sacrificed to collect livers in ice bath. Liver Hg, GSH and MDA content as well as SOD and GPx activities were determined. The livers of the other four rats in each group were used to make single cell suspension for detection of reactive oxygen species （ROS） and early cell apoptosis. Results Compared with the control group, after different concentrations of HgCl2 exposure, the hepatic Hg, GSH, MDA and ROS level as well as early cell apoptosis rate increased , while SOD and GPx activities decreased, all in a dose-dependent manner （P〈0.01）.The above changes in the 2.4 mg/kg HgCl2-treated group had significant differences （P〈0.05 or P〈0.01 ）. SFN pre-treatment significantly antagonized Hg-induced liver oxidative stress, characterized by significant decrease in GSH, MDA and ROS levels and early cell apoptosis rate as well as obvious increase in SOD and GPx activities when compared with those in 2.4 mg/kg HgCl2-treated group （P〈0.05 or P〈0.01 ）. Conclusion SFN can antagonize Hg -induced liver oxidative stress to a certain extent.