吕佳鑫, 马璐, 张爱华. 组蛋白H3K36me3在砷致大鼠肝氧化损伤中的作用[J]. 环境与职业医学, 2021, 38(6): 637-642. DOI: 10.13213/j.cnki.jeom.2021.20542
引用本文: 吕佳鑫, 马璐, 张爱华. 组蛋白H3K36me3在砷致大鼠肝氧化损伤中的作用[J]. 环境与职业医学, 2021, 38(6): 637-642. DOI: 10.13213/j.cnki.jeom.2021.20542
LYU Jiaxin, MA Lu, ZHANG Aihua. Role of histone H3K36me3 in hepatic oxidative damage induced by arsenic in rats[J]. Journal of Environmental and Occupational Medicine, 2021, 38(6): 637-642. DOI: 10.13213/j.cnki.jeom.2021.20542
Citation: LYU Jiaxin, MA Lu, ZHANG Aihua. Role of histone H3K36me3 in hepatic oxidative damage induced by arsenic in rats[J]. Journal of Environmental and Occupational Medicine, 2021, 38(6): 637-642. DOI: 10.13213/j.cnki.jeom.2021.20542

组蛋白H3K36me3在砷致大鼠肝氧化损伤中的作用

Role of histone H3K36me3 in hepatic oxidative damage induced by arsenic in rats

  • 摘要: 背景

    环境污染物致机体健康损害是国内外学者关注的焦点,组蛋白H3第36位赖氨酸三甲基(H3K36me3)作为砷暴露敏感的表观遗传修饰靶点之一,其介导的砷致肝损害机制研究目前尚不清楚。

    目的

    探讨砷暴露大鼠肝脏组蛋白H3K36me3修饰水平与砷致肝氧化损伤的关系,从表观遗传学角度为深化认识砷致肝氧化损伤机制及其干预研究提供新思路。

    方法

    32只健康初断乳Wistar大鼠,雌雄各半,按体重采用随机数字表法分为对照组,低、中、高染砷剂量组,每组8只。大鼠亚砷酸钠半数致死量(LD50)为41 mg·kg-1,按照亚慢性毒性试验剂量设计原则,低、中、高染砷组分别给予2.5(1/16 LD50)、5.0(1/8 LD50)、10.0(1/4LD50)mg·kg-1(以体重计,后同)亚砷酸钠溶液,对照组给予去离子水,灌胃染毒,灌胃量为10 mL·kg-1,每周连续染毒6 d,共处理4个月。实验终期采集大鼠尿样、肝脏样本。采用电感耦合等离子质谱(ICP-MS)检测肝脏中砷的质量分数,酸抽提法提取大鼠肝脏组蛋白,酶联免疫吸附实验(ELISA)检测肝脏中H3K36me3的质量分数,超高效液相色谱-串联四级杆质谱(UPLC-MS/MS)检测尿8-羟基脱氧鸟苷(8-OHdG)的质量浓度,硫代巴比妥酸法(TBA法)检测肝脏丙二醛(MDA)的质量摩尔浓度。分析肝砷、H3K36me3、8-OHdG、MDA之间的线性相关关系,并建立“肝砷—H3K36me3—8-OHdG/MDA”中介检验模型以探索H3K36me3在砷致肝氧化损伤中的中介作用。

    结果

    低、中、高砷剂量组肝砷、尿8-OHdG、肝MDA水平分别高于对照组,而肝H3K36me3水平低于对照组(均P < 0.05);且随染砷剂量的增加,肝砷、尿8-OHdG和肝MDA水平逐渐升高,H3K36me3修饰水平逐渐降低(P趋势 < 0.01)。相关性分析也显示肝砷水平与尿8-OHdG、肝MDA水平呈正相关(r=0.701、0.748,均P < 0.01),与肝H3K36me3修饰水平呈负相关(r=-0.715,P < 0.01);肝H3K36me3修饰水平与尿8-OHdG、肝MDA水平呈负相关(r=-0.660、-0.683,均P < 0.01);尿中8-OHdG水平与肝中MDA水平呈正相关(r=0.778,P < 0.01)。H3K36me3在砷致8-OHdG和MDA水平的中介效应分别占总效应的30.97%、38.91%。

    结论

    砷致大鼠肝脏H3K36me3水平降低可能参与肝氧化损伤的调控,H3K36me3有望是砷致肝氧化损伤机制研究的新靶点。

     

    Abstract: Background

    Environmental pollutants can cause human health damage, which has become a research focus of domestic and foreign scholars. Histone H3 lysine 36 trimethylation (H3K36me3) is one of the sensitive targets of epigenetic modification due to arsenic exposure, and the mechanism of arsenic induced liver damage is still unclear.

    Objective

    This experiment evaluates the association of H3K36me3 and hepatic oxidative damage induced by arsenic in rats, providing an epigenetic understanding of the mechanism and intervention of arsenic induced liver oxidative damage from the perspective of epigenetics.

    Methods

    Thirty-two healthy weaned Wistar rats were randomly divided into a control group and three arsenic groups (low, medium, and high dose groups), with eight rats in each group. The median lethal dose (LD50) of sodium arsenite in rats was 41 mg·kg-1. According to the principle of dose design for subchronic toxicity test, the three arsenic dose groups were given 2.5 (1/16 LD50), 5.0 (1/8 LD50), and 10.0 (1/4 LD50) mg·kg-1 (calculated by body weight, thereafter) sodium arsenite solution respectively. The rats in the control group were given 10 mL·kg-1 deionized water by intragastric administration, 6 d a week. After 4 months, urine and liver tissue samples were collected. The content of arsenic in liver was measured by inductively coupled plasma mass spectrometry (ICP-MS). Histone was extracted from the liver of rats by acid extraction, and the modification level of H3K36me3 was detected by enzyme-linked immunosorbent assay (ELISA). The level of urinary 8-hydroxy-2-deoxyguanosine (8-OHdG) was tested by the ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The content of liver malondialdehyde (MDA) was determined by thiobarbituric acid (TBA) method. The linear relationships between liver arsenic, H3K36me3, 8-OHdG, and MDA were evaluated. A "liver arsenic-H3K36me3-8-OHdG/MDA" mediation model was established to explore potential mediating role of H3K36me3 in arsenic induced liver oxidative injury.

    Results

    The levels of hepatic arsenic, urinary 8-OHdG, and hepatic MDA in the low, medium, and high arsenic groups were higher than the levels in the control group, while the level of hepatic H3K36me3 in the three arsenic dose groups were lower (P < 0.05). The levels of hepatic arsenic, urinary 8-OHdG, and hepatic MDA increased with higher arsenic doses (Ptrend < 0.01), while the level of H3K36me3 in liver decreased with higher arsenic doses (Ptrend < 0.01). Hepatic arsenic level had a positive correlation with urinary 8-OHdG and hepatic MDA levels (r=0.701, 0.748, P < 0.01), but had a negative correalation with liver H3K36me3 modification (r=-0.715, P < 0.01). Liver H3K36me3 modification was negatively correlated with urinary 8-OHdG and hepatic MDA levels (r=-0.660, -0.683, P < 0.01). Urinary 8-OHdG level was positively correlated with hepatic MDA level (r=0.778, P < 0.01). The mediating effect of H3K36me3 on arsenic induced 8-OHdG and MDA levels accounted for 30.97% and 38.91% of the total effect, respectively.

    Conclusion

    The decreased H3K36me3 in rat liver induced by arsenic may be involved in the regulation of hepatic oxidative damage, suggesting that H3K36me3 may be used as a new target for studying the mechanism of hepatic oxidative damage.

     

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