朱为梅, 赵红宇, 杨海清, 罗宇超, 李学章. 低浓度铅和高脂饲料对大鼠肝脏的影响[J]. 环境与职业医学, 2019, 36(5): 490-495. DOI: 10.13213/j.cnki.jeom.2019.18644
引用本文: 朱为梅, 赵红宇, 杨海清, 罗宇超, 李学章. 低浓度铅和高脂饲料对大鼠肝脏的影响[J]. 环境与职业医学, 2019, 36(5): 490-495. DOI: 10.13213/j.cnki.jeom.2019.18644
ZHU Wei-mei, ZHAO Hong-yu, YANG Hai-qing, LUO Yu-chao, LI Xue-zhang. Effects of low-lead and high-fat diet on rat liver[J]. Journal of Environmental and Occupational Medicine, 2019, 36(5): 490-495. DOI: 10.13213/j.cnki.jeom.2019.18644
Citation: ZHU Wei-mei, ZHAO Hong-yu, YANG Hai-qing, LUO Yu-chao, LI Xue-zhang. Effects of low-lead and high-fat diet on rat liver[J]. Journal of Environmental and Occupational Medicine, 2019, 36(5): 490-495. DOI: 10.13213/j.cnki.jeom.2019.18644

低浓度铅和高脂饲料对大鼠肝脏的影响

Effects of low-lead and high-fat diet on rat liver

  • 摘要: 背景 慢性低浓度铅(后简称"低铅")中毒已成为影响人们健康的一大疾病,尤其是当肝脏自身受到炎症、脂肪等浸润时,其排铅能力明显降低,会加重肝脏的损害,其作用机制可能与细胞凋亡有关。

    目的 本研究拟从肝细胞凋亡途径探讨低铅对非酒精性脂肪肝病大鼠的影响,以进一步明确低铅在肝脏损害中的作用。

    方法 适应性喂养2周后,60只SD大鼠随机均分为4组,为普通饲料组(后称"普通组")、低铅普通饲料组(后称"低铅组")、高脂饲料组(后称"高脂组")和低铅高脂饲料组(后称"低铅高脂组"),每组15只。相应饲料喂养8周后处死。采集肝脏和血液,检测血铅和肝铅含量,观察光镜下肝脏形态学变化,观察其肝功能指标血清谷草转氨酶(AST)和谷丙转氨酶(ALT)、抗氧化指标血清超氧化物歧化酶(SOD)、丙二醛(MDA)、谷胱甘肽(GSH)和总抗氧化能力(T-AOC),并采用Western blot和逆转录-聚合酶链反应(RT-PCR)检测凋亡相关Bax、bcl-2、P53和Fas蛋白和mRNA的表达。

    结果 低铅组和低铅高脂组大鼠血铅和肝铅含量明显高于普通组(P < 0.05),且低铅高脂组血铅(0.31±0.10)mg/L和肝铅(3.37±1.12)mg/L明显高于低铅组(0.26±0.10)mg/L,(2.42±0.87)mg/L(P < 0.05)。HE染色显示:普通组大鼠肝脏细胞排列紧密,细胞核大小均一;低铅组看不出明显损伤;高脂组和低铅高脂组有明显脂肪空泡,特别是低铅高脂组,脂肪空泡数量更多,表明大鼠非酒精性脂肪肝病模型建成。低铅组、高脂组和低铅高脂组ALT和AST均明显高于普通组(P < 0.05);高脂组和低铅高脂组ALT和AST明显高于低铅组(P < 0.05);低铅高脂组ALT和AST明显高于高脂组(P < 0.05)。低铅组SOD、GSH、T-AOC和MDA与普通组没有差异;相较于普通组,高脂组和低铅高脂组SOD、GSH和T-AOC明显降低(P < 0.05),MDA明显升高(P < 0.05);相较于低铅普通组,高脂组和低铅高脂组SOD、GSH和T-AOC明显降低(P < 0.05),MDA明显升高(P < 0.05);相较于高脂组,低铅高脂组SOD、GSH和T-AOC明显降低(P < 0.05),MDA明显升高(P < 0.05)。Western Blot和RT-PCR分析结果可见:P53、Fas和Bax表达,普通组和低铅组没有差异,而高脂组和低铅高脂组高于普通组和低铅组(P < 0.05),低铅高脂组(p53、Fas和Bax蛋白分别为:1.57±0.14、1.16±0.08和1.34±0.12;mRNA分别为:3.35±0.14、2.52±0.08和2.25±0.06)高于高脂组(p53、Fas和Bax蛋白分别为:1.35±0.10、0.98±0.06和1.15±0.09;mRNA分别为:2.75±0.16、1.82±0.04和1.72±0.05)(P < 0.05);bcl-2蛋白表达,普通组和低铅组没有差异,高脂组(0.52±0.05)和低铅高脂组(0.50±0.04)低于普通组(1.18±0.04)和低铅组(1.14±0.03)(P < 0.05),低铅高脂组和高脂组没有差异;而低铅高脂组的bcl-2 mRNA表达低于其余3组(P < 0.05)。

    结论 低浓度铅可致非酒精性脂肪肝病大鼠肝功能异常,降低其抗氧化能力,这可能与低铅可以加重非酒精性脂肪肝病大鼠肝细胞凋亡有关。

     

    Abstract: Background Chronic low lead poisoning affects human health; especially when liver is experiencing inflammatory and fatty infiltration, it removes less lead and the damage aggravates, which may be related to cell apoptosis.

    Objective This study is designed to investigate the effects of low lead on hepatocyte apoptosis in rats with non-alcoholic fatty liver disease (NAFLD), and clarify the role of low lead in liver damage.

    Methods After two weeks of adaptive feeding, 60 rats were randomly divided into four groups:normal diet group, low Pb group, high fat diet group, and low Pb+high fat diet group, with 15 rats in each group. They were sacrificed after feeding with corresponding diet plans for eight weeks. Liver and blood samples were collected to detect blood and liver lead levels, liver function indicesaspartate transaminase (AST) and alanine transaminase (ALT), and antioxidant indicessuperoxide dismutase (SOD), malondialdehyde (MDA), glutathione (GSH), and total antioxidant capacity (T-AOC), as well as to observe liver pathological alteration under light microscope. The protein and mRNA expressions of Bax, bcl-2, P53, and Fas were measured by Western blot and reverse transcription-polymerase chain reaction (RT-PCR), respectively.

    Results The levels of blood lead and liver lead in the low Pb group and the low Pb+high fat diet group were significantly higher than those in the normal diet group (P < 0.05), and the levels in the low Pb+high fat diet groupblood lead:(0.31±0.10) mg/L; liver lead:(3.37±1.12)mg/L were significantly higher than those in the low Pb groupblood lead:(0.26±0.10)mg/L; liver lead:(2.42±0.87)mg/L (P < 0.05). The results of HE staining showed that cells on rat liver in the normal diet group were closely arranged with uniform nucleus size; the low Pb group did not show obvious damage; the high fat diet group and the low Pb+high fat diet group showed fat vacuoles, especially the low Pb+high fat diet group, indicating an established rat model of NAFLD. For AST and ALT, the low Pb group, the high fat diet group, and the low Pb+high fat diet group showed higher levels than the normal diet group (P < 0.05); the high fat diet group and the low Pb+high fat diet group showed higher levels than the low Pb group (P < 0.05); the low Pb+high fat diet group showed higher levels than the high fat diet group (P < 0.05). Compared with the normal diet group, the low Pb group had no differences in SOD, GSH, T-AOC, and MDA, but the high fat diet group and the low Pb+high fat diet group showed reduced SOD, GSH, and T-AOC (P < 0.05) and increased MDA (P < 0.05). Compared with the low Pb group, the high fat diet group and the low Pb+high fat diet group showed decreased SOD, GSH, and T-AOC (P < 0.05) and increased MDA (P < 0.05). Compared with the high fat diet group, the low Pb+high fat diet group showed reduced SOD, GSH, and T-AOC (P < 0.05) and elevated MDA (P < 0.05). According to the results of Western blot and RT-PCR, the expressions of P53, Fas, and Bax between the normal diet group and the low Pb group were not different; but the high fat diet group and the low Pb+high fat diet group showed significantly higher levels of the expressions than the normal diet group and the low Pb group (P < 0.05), and the low Pb+high fat diet group (protein expression levels of p53, Fas, and Bax were 1.57±0.14, 1.16±0.08, and 1.34±0.12, respectively; mRNA expression levels were 3.35±0.14, 2.52±0.08, and 2.25±0.06, respectively) showed significantly higher levels of the expressions than the high fat diet group (protein expression levels of p53, Fas, and Bax were 1.35±0.10, 0.98±0.06, and 1.15±0.09, respectively; mRNA expression levels were 2.75±0.16, 1.82±0.04, and 1.72±0.05, respectively) (P < 0.05). The expressions of bcl-2 protein between the normal diet group and the low Pb group were not different, but the high fat diet group (0.52±0.05) and the low Pb+high fat diet group (0.50±0.04) showed significantly lower levels than the normal diet group (1.18±0.04) and the low Pb group (1.14±0.03) (P < 0.05), and there was no difference between the low Pb+high fat diet group and the high fat diet group; the low Pb group showed significantly lower level of expression of bcl-2 mRNA than the other three groups (P < 0.05).

    Conclusion Low lead can exacerbate liver dysfunction and decrease antioxidant capacity in rats with NAFLD, which may be related to aggravated hepatocyte apoptosis induced by low lead.

     

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