亚硫酸钠对HepG2细胞毒性的实验研究

目的观察食品添加剂亚硫酸钠对人肝肿瘤细胞(HepG2)的细胞毒性作用和脂肪变作用。方法向HepG2细胞悬液中分别加入终浓度为0(阴性对照)～10 mmol/L亚硫酸钠溶液染毒24、48和72 h,并设空白对照(无细胞)组和阳性对照组(含1%Tritonx-100的DMEM),每组6个复孔。采用乳酸脱氢酶(LDH)活力测定法检测肝细胞膜的通透性变化,采用CCK-8法检测肝细胞的活性改变,采用油红O染色法观察肝细胞内脂肪沉积情况。结果与阴性对照组相比,仅10 mmol/L亚硫酸钠染毒24 h后HepG2细胞培养上清中LDH活力的释放率增加(P<0.05);而各剂量亚硫酸钠染毒48和72 h后HepG2细胞培养上清中LDH活力的释放率无显著变化。与阴性对照组相比,各剂量亚硫酸钠染毒24、48、72 h后(除0.039 mmol/L染毒72 h外)HepG2细胞的存活率均显著下降(P<0.05),且细胞存活率随着亚硫酸钠染毒剂量的升高而降低。染毒24、48 h后,部分亚硫酸钠染毒组HepG2细胞内出现了极少量的脂滴,而阴性对照组却未发现;染毒72 h后,10 mmol/L亚硫酸钠染毒组出现明显脂滴。结论一定剂量的亚硫酸钠染毒可增加HepG2细胞膜的通透性,对肝细胞活性有明显的抑制作用,并且可引起肝细胞内甘油三酯的蓄积。     

Toxicity of Sodium Sulfite to HepG2 Hepatocytes

目的 观察食品添加剂亚硫酸钠对人肝肿瘤细胞( HepG2)的细胞毒性作用和脂肪变作用.方法向HepG2细胞悬液中分别加入终浓度为0(阴性对照)～ 10 mmol/L亚硫酸钠溶液染毒24、48和72 h,并设空白对照(无细胞)组和阳性对照组(含1％Tritonx -100的DMEM),每组6个复孔.采用乳酸脱氢酶(LDH)活力测定法检测肝细胞膜的通透性变化,采用CCK-8法检测肝细胞的活性改变,采用油红O染色法观察肝细胞内脂肪沉积情况.结果 与阴性对照组相比,仅10 mmol/L亚硫酸钠染毒24h后HepG2细胞培养上清中LDH活力的释放率增加(P＜0.05);而各剂量亚硫酸钠染毒48和72 h后HepG2细胞培养上清中LDH活力的释放率无显著变化.与阴性对照组相比,各剂量亚硫酸钠染毒24、48、72 h后(除0.039 mmol/L染毒72 h外)HepG2细胞的存活率均显著下降(P＜0.05),且细胞存活率随着亚硫酸钠染毒剂量的升高而降低.染毒24、48 h后,部分亚硫酸钠染毒组HepG2细胞内出现了极少量的脂滴,而阴性对照组却未发现;染毒72 h后,10 mmol/L亚硫酸钠染毒组出现明显脂滴.结论 一定剂量的亚硫酸钠染毒可增加HepG2细胞膜的通透性,对肝细胞活性有明显的抑制作用,并且可引起肝细胞内甘油三酯的蓄积.     

槟榔碱对L-02细胞损伤的研究

目的探讨槟榔碱对L-02细胞损伤及其可能的作用机制。方法将处于对数生长期的L-02细胞分别暴露于终浓度为0(对照)、3、9、18、36、75、150、300 mg/L槟榔碱溶液培养24 h,检测细胞活性、乳酸脱氢酶(LDH)漏出情况和丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)活力及线粒体膜电位。结果与对照组比较,仅150、300 mg/L槟榔碱染毒L-02细胞存活率和线粒体膜电位均较低,而150、300 mg/L槟榔碱染毒L-02细胞的LDH漏出率和AST活力及300 mg/L槟榔碱染毒L-02细胞的ALT活力均较高,差异有统计学意义(P0.05);且随着槟榔碱染毒剂量的升高,L-02细胞存活率和线粒体膜电位呈下降趋势,而LDH漏出率及ALT、AST活力均呈上升趋势。结论槟榔碱可能通过损伤细胞膜而对L-02细胞产生毒性。     

亚硫酸钠对人正常二倍体肝细胞的损伤作用程序性坏死相关蛋白受体相互作用蛋白1表达的影响

目的探讨亚硫酸钠对人正常二倍体肝细胞(HL-7702)的损伤作用及程序性坏死相关蛋白受体相互作用蛋白1(RIP1)表达的影响。方法将处于对数生长期的HL-7702细胞分别暴露于含终浓度为0(对照)、0.01、0.1、1、10 mmol/L亚硫酸钠的培养基中培养2、4、12、24、48 h。采用CCK-8法检测细胞活性,采用全自动生化分析仪检测细胞上清液中丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)以及乳酸脱氢酶(LDH)的活力,采用Western Blot法检测细胞RIP1蛋白的表达水平。结果与对照组相比,1、10 mmol/L亚硫酸钠染毒不同时间的HL-7702细胞存活率降低,差异有统计学意义(P0.05);且随着亚硫酸钠染毒浓度的升高,HL-7702细胞的存活率呈下降趋势。与对照组相比,仅10 mmol/L亚硫酸钠染毒24、48 h HL-7702细胞上清液中的ALT活力较高;1 mmol/L亚硫酸钠染毒4、24 h及10 mmol/L亚硫酸钠染毒2、4 h HL-7702细胞上清液中的AST活力较低,而10 mmol/L亚硫酸钠染毒24、48 h HL-7702细胞上清液中的AST活力较高;10 mmol/L亚硫酸钠染毒2、4 h HL-7702细胞上清液中的LDH活力较低,而染毒24、48 h HL-7702细胞上清液中的LDH活力较高,差异均有统计学意义(P0.05)。与对照组相比,各浓度亚硫酸钠染毒组HL-7702细胞中RIP1蛋白的表达水平均较高,差异多有统计学意义(P0.05)。结论程序性坏死可能参与了亚硫酸钠引起的肝细胞死亡,但其可能机制还有待于进一步研究。     

草苁蓉多糖对张氏肝细胞氧化损伤保护作用

目的探讨草苁蓉多糖对过氧化氢(H_2O_2)致张氏肝细胞氧化损伤的保护作用及机制。方法以张氏肝细胞为研究对象,用H_2O_2诱导建立细胞氧化应激损伤模型,噻唑蓝法检测细胞存活率;分光光度法测定细胞外液中谷丙转氨酶(ALT)、谷草转氨酶(AST)、乳酸脱氢酶(LDH)及细胞中丙二醛(MDA)、还原型谷胱甘肽(GSH)和超氧化物歧化酶(SOD)含量。结果与对照组比较,模型组肝细胞存活率[(52.5±1.2)%]下降,细胞外液中ALT、AST、LDH活力[分别为(23.5±2.9)、(29.4±2.9)、(595.4±5.6)U/L]升高,细胞中SOD活性和GSH含量[分别为(163.1±6.1)U/mg prot、(8.91±1.26)mg/g prot]下降,丙二醛含量[(12.6±2.6)nmol/mg prot]升高;与模型组比较,50 mg/L草苁蓉多糖组肝细胞存活率[(79.0±5.5)%]升高,细胞外液中ALT、AST、LDH活力[分别为(10.4±2.9)、(14.4±3.2)、(374.4±12.5)U/L]降低,细胞中SOD活性和GSH含量[分别为(323.6±17.3)U/mg prot、(15.4±0.52)mg/g prot]升高,细胞MDA含量[(6.93±0.75)nmol/mg prot]降低。结论草苁蓉多糖对H_2O_2所致张氏肝细胞损伤具有一定保护作用,其机制可能与提高细胞抗氧化能力有关。     

氢醌对L-02肝细胞损伤的研究

[目的]探讨氢醌(HQ)对L-02肝细胞损伤及其可能的作用机制。[方法]应用噻唑蓝(MTT)比色法检测浓度分别为0、5、10、20、40、80、160和320gmol/L的HQ作用24h后对L-02肝细胞存活率的影响;利用万能倒置显微镜观察不同浓度HQ染毒之后L-02肝细胞的形态学改变并摄影成像;利用全自动生化分析仪检测不同浓度HQ染毒24h后L-02肝细胞的乳酸脱氢酶(LDH)漏出率和丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)活性,以观察HQ对L-02肝细胞膜完整性的影响。[结果]在0～80μmol/L浓度的范围内染毒24h后,HQ对L-02肝细胞的存活率没有明显的影响(P>0.05);浓度≥160μmol/L时,染毒24h后,存活率则明显下降(P<0.01),LDH漏出率、ALT和AST活性均有随着HQ浓度的增加而升高的趋势;160和320μmol/L组LDH漏出率与对照组比较有明显升高(P<0.01)。但ALT和AST活性只在320μmol/L组与对照组比较才有明显增加(P<0.01)。此外,160和320μmol/L组L-02肝细胞的形态与对照组相比发生了明显的改变。[结论]HQ可能是通过损伤细胞膜而对L-02肝细胞产生毒性影响。     

苯乙烯对大鼠血及肝组织中脂质过氧化作用的影响

目的探讨苯乙烯(styrene)的氧化损伤效应。方法40只成年大鼠被随机分为1个对照组和3个实验组,实验组苯乙烯染毒剂量分别为(1/16 LD50、1/8 LD50、1/4 LD50),每天灌胃1次,连续染毒4周,对照组给予等量芝麻油。测定血及肝组织中还原型谷胱甘肽(GSH)、丙二醛(MDA)含量及谷胱甘肽过氧化物酶(GSH-Px)活力。结果各染毒剂量组血及肝组织中GSH含量及GSH-Px活力与对照组比较,差异均无统计学意义;低剂量染毒组血清中MDA含量为(3.68±0.72)nmol/ml,与对照组[(4.72±0.95)nmol/ml]比较,显著下降(P<0.05);肝组织中MDA含量随染毒剂量增加而增加,但与对照组比较,差异均无统计学意义。结论在本次实验条件下,苯乙烯未能引起大鼠血及肝组织的脂质过氧化损伤。     

铅的肾细胞毒性及钙拮抗剂的干预作用

目的 探讨醋酸铅对大鼠肾细胞(NRK)的毒作用及钙拮抗剂的干预作用.方法 用醋酸铅对NRK细胞染毒,观察细胞存活率的变化,测定细胞上清液中N-乙酰-β-D-氨基葡萄糖苷酶(NAG)和谷氨酰转肽酶(γ-GT)活力的改变.同时利用钙拮抗剂尼莫地平进行干预,并检测上述指标的变化.结果 随着醋酸铅染毒剂量的增加,细胞存活率逐渐降低.0.02、0.10、0.50 mmol/L铅染毒组细胞上清液中NAG活力分别为(8.37±0.19)、(9.13±0.27)和(10.32±0.48)U/L,均明显高于对照组[(7.08±0.24)U/L1,差异有统计学意义(P＜0.05);各染毒组γ-GT的活力分别为(75.22±7.35)、(101.45±8.87)和(117.71±8.35)U/L,而对照组为(67.23±6.64)U/L,其中0.10、0.50mmoL/L染毒组γ-GT的活力明显高于对照组,差异有统计学意义(P＜0.05).钙拮抗剂干预结果显示,当尼莫地平的剂量为10、20 μmol/L时,细胞存活率分别为96.67%±1.33%、97.48%±2.15%,NAG活力分别为(7.11±0.35)、(7.06±0.23)U/L,γ-GT活力分别为(74.75±3.23)、(72.26±5.59)U/L,均明显低于0.10 mmol/L醋酸铅染毒组,差异有统计学意义(P＜0.05),与对照组比较,差异无统计学意义(P＞0.05).而尼莫地平剂量为5 μmol/L时无明显的干预效果.结论 铅对NRK细胞具有明显的细胞毒性,细胞上清液中NAG活力的变化可反映铅对NRK细胞的早期毒性;钙拈抗剂对铅致NRK细胞的毒性具有保护作用,且与剂量有关.     

多氯联苯诱导小胶质细胞凋亡及钙离子紊乱

目的探究多氯联苯(polychlorinated biphenyl,PCB)对小胶质细胞的神经毒作用及机制。方法实验分为对照组及PCB118、138、153、180染毒组,染毒剂量分别为0.000、0.015、0.030、0.050、0.100、0.150μmol/L。通过对细胞存活率检测结果进行统计学分析,最终确定后续实验染毒剂量分为低、中、高3个剂量水平,其中除PCB118高剂量组为0.15μmol/L外,低剂量组均为0.015μmol/L,中剂量组为0.05μmol/L,高剂量组为0.1μmol/L。体外培养小鼠小胶质细胞经不同剂量PCB染毒后,CCK-8法检测细胞生长活性;FITC Annexin V/PI双染法检测细胞凋亡率;ELISA法检测乳酸脱氢酶(LDH)释放量;荧光探针法(Fluo-4 AM)检测细胞内钙离子含量变化。结果 PCB118、138、153、180均能抑制细胞活性,并随染毒剂量增加细胞存活率降低,凋亡率升高。PCB118染毒剂量在0.15μmol/L时毒作用明显增强,存活率降低至(66.56±0.10)%,凋亡率升高至(27.39±1.80)%;PCB138、153在0.1μmol/L时存活率为(66.66±0.10)%、(67.17±0.12)%,凋亡率达到(48.77±2.43)%及(56.42±3.59)%;PCB180染毒剂量为0.015μmol/L时细胞存活率为(92.07±0.38)%,凋亡率为(6.82±0.51)%,显著高于对照组,差异有统计学意义(P0.05)。LDH释放量与染毒剂量成正比,低剂量PCB118、138、153、180 LDH释放量分别为(523.78±13.58)、(430.37±22.03)、(540.58±13.08)和(411.88±21.92)U/L,均明显高于对照组,差异有统计学意义(P0.05)。PCB染毒组细胞内钙离子(Ca~(2+))平均荧光强度明显增强,染毒剂量在0.015μmol/L时PCB118、138、153、180组细胞内Ca~(2+)平均荧光强度分别为(10.14±2.36)、(32.47±1.56)、(16.54±0.97)和(40.46±2.19),显著高于对照组,差异有统计学意义(P0.05)。结论多氯联苯可以引起神经毒性,升高LDH,破坏细胞膜完整性,使胞内钙离子增加,导致细胞凋亡。     

不同地区大气PM2.5对大鼠肺泡巨噬细胞毒性作用的实验研究

目的比较不同地区大气PM2.5对肺泡巨噬细胞的毒性作用。方法采集广州市、东莞市、深圳市和肇庆市4个地区的大气PM2.5,将PM2.5分别以1、10、50、100、200、300μg/ml剂量对肺泡巨噬细胞染毒24 h。检测一氧化氮(NO)释放量、超氧化物歧化酶(SOD)活力、丙二醛(MDA)生成量、肿瘤坏死因子(TNF-α)水平、乳酸脱氢酶(LDH)漏出率及细胞存活率。以肇庆作为对照,观察PM2.5对各指标的影响。经剂量与效应指标回归分析,以斜率评价各地区PM2.5的效应大小。结果不同地区大气PM2.5致肺泡巨噬细胞释放TNF-α、NO、MDA的水平和LDH的漏出率均随着染毒剂量增加而升高,SOD的活力和细胞的存活率随染毒剂量升高而降低。深圳和东莞大气PM2.5对肺泡巨噬细胞胞内的SOD活力的抑制程度高于广州和肇庆(P<0.05)。深圳和东莞大气PM2.5致肺泡巨噬细胞内MDA的生成量明显高于肇庆(P<0.05)。广州大气PM2.5致肺泡巨噬细胞生成TNF-α量最高,其次为东莞,均明显高于肇庆(P<0.05)。广州大气PM2.5致肺泡巨噬细胞内LDH的漏出率最高,其次为东莞和深圳,均高于肇庆(P<0.05)。剂量高于100μg/ml时,广州、深圳和东莞大气PM2.5致肺泡巨噬细胞存活率低于肇庆(P<0.05)。回归分析显示,广州大气PM2.5对肺泡巨噬细胞的TNF-α、LDH漏出率、NO释放量的效应最强,肇庆大气PM2.5对肺泡巨噬细胞的LDH漏出率、NO释放量和细胞存活率的效应最低。结论不同地区大气PM2.5对大鼠肺泡巨噬细胞的毒性作用随染毒剂量增加而增强,广州、东莞、深圳地区大气PM2.5的毒性效应总体上强于肇庆地区。     

Blood styrene and urinary metabolites in styrene polymerisation.

The results of the analysis of blood and urine samples for styrene and its metabolites in 491 workers in a styrene polymerisation plant in the United States are reported. The levels of exposure to styrene were estimated to be less than 10 ppm, but nevertheless styrene and metabolites were detectable in more than 50% of workers in polymerisation jobs, within 4 h of exposure. Workers involved in the manufacture and purification of styrene from ethyl benzene also had detectable blood styrene and urinary metabolites in 83% of recently exposed subjects. The relationship between styrene in blood and in subcutaneous fat and urinary metabolites as pharmacokinetic variables is discussed.     

Ototoxic effects of occupational exposure to styrene and co-exposure to styrene and noise

Ototoxicity of styrene and the synergistic action of styrene and noise have been shown in rats. The respective data in humans are scarce and equivocal. This study evaluated the effects of occupational exposure to styrene and combined exposures to styrene and noise on hearing. The study group, comprised of 290-yacht yard and plastic factory workers, was exposed to a mixture of organic solvents, having styrene as its main compound. The reference group, totaling 223 subjects, included (1) white-collar workers, exposed neither to solvents nor noise and (2) metal factory workers, exposed exclusively to noise. All subjects were assessed by means of a detailed questionnaire and underwent otorhinolaryngological and audiometric examinations. Multiple logistic regression analysis revealed almost a 4-fold (or 3.9; 95% CI = 2.4-6.2) increase in the odds of developing hearing loss related to styrene exposure. The factors adjusted for were: age, gender, current occupational exposure to noise, and exposure to noise in the past. In cases of the combined exposures to styrene and noise, the odds ratios were two to three times higher than the respective values for styrene-only and noise-only exposed subjects. The mean hearing thresholds--adjusted for age, gender, and exposure to noise--were significantly higher in the solvent-exposed group than in the unexposed reference group at all frequencies tested. A positive linear relationship existed between an averaged working life exposure to styrene concentration and a hearing threshold at the frequencies of 6 and 8 kHz. This study provides the epidemiological evidence that occupational exposure to styrene is related to an increased risk of hearing loss. Combined exposures to noise and styrene seem to be more ototoxic than exposure to noise alone.     

苯乙烯及7,8-氧化苯乙烯对人淋巴细胞DNA的损伤

目的　探讨苯乙烯的遗传毒性机制。方法　采用碱性单细胞凝胶电泳(SCGE)方法,分离健康人外周血淋巴细胞,在体外用苯乙烯或其中间代谢产物7,8 氧化苯乙烯(SO)染毒1 h后,测量彗星尾长。结果　苯乙烯0. 100、0. 200、0. 400 mmol/L染毒组的彗星尾长分别为(12. 06±5. 82)、(9.25±3.24)、(8.60±4.30)μm,与空白及溶剂对照组[(6.69±2.17)、(6.56±0.96)μm]的差异有统计学意义(P<0.05)。SO 0.050、0.100、0.200、0.400 mmol/L组彗星尾长分别为(11.35±4.32)、(15.05±4.11)、(20.10±2.11)、(26.64±2.16)μm,与空白及溶剂对照组[(7.20±2.85)、(6.95±1.88)μm]的差异均具有统计学意义(P<0.05),并呈现出明显的剂量-反应关系(r=0.97,P=0.006)。结论　苯乙烯及SO均可致人淋巴细胞DNA的断裂,SO的作用强于苯乙烯。     

Occurrence of styrene-7,8-oxide and styrene glycol in mouse after the administration of styrene

Styrene-7,8-oxide and its hydrated product styrene glycol were determined in mouse tissues at different times (0.5-5 h) after the intraperitoneal administration of 7-[14C]-styrene (3.8 mmol/kg). In a study of the influence of dose on the metabolite pattern of styrene, mice were killed 2 h after a dose of 1.1, 2.3, 3.4, and 5.1 mmol/kg, respectively. The mouse tissues studied (blood, liver, kidney, lung, brain, subcutaneous adipose tissue) were isolated and extracted first with hexane to remove styrene and styrene-7,8-oxide and then with ethyl acetate to remove styrene glycol. beta-Glucuronidase was used to liberate conjugated styrene glycol. A gas-liquid chromatographic method based on the use of an electron capture detector (GLC-EC) was used to quantify styrene glycol, as well as styrene-7,8-oxide, after hydrolysis. In addition all homogenates and extracts were assayed by radioactivity counting. Styrene-7,8-oxide and styrene glycol reached maximum concentrations within 2 h. The highest levels of styrene-7,8-oxide were detected in the kidneys and subcutaneous adipose tissue, while the lungs showed the lowest levels. Styrene glycol was found in the highest concentrations in the kidneys, liver, blood, and lungs. The concentration of unmetabolized styrene increased exponentially at higher doses. There seemed to be a linear increase with the dose of styrene-7,8-oxide and styrene glycol in all the tissues studied. The more polar metabolites occurred at relatively lower levels in the liver and kidneys at higher doses. In a complementary study the epoxide hydratase inhibitor trichloropropene oxide was added to the removed tissues, and the hexane extracts were analyzed for styrene-7,8-oxide both by GLC-EC and mass spectrometry (GLC-MS).     

Human exposure to styrene

Summary The derivatization of phenylglyoxylic acid (PGA), a urinary styrene metabolite, gives with diazomethane under ordinary reaction conditions secondary products as expected from the behaviour of other -keto acids. Thus reproducible quantitative analysis becomes difficult. It is shown that by proper selection of reaction conditions (low temperature, short reaction time) these secondary transformations can be inhibited and exclusive derivatization to the methylester is obtained. A quantitative determination of urinary PGA can be based on this derivatization procedure. However, this method is not considered suitable for routine monitoring due to the delicate reaction conditions necessary. The results are discussed with reference to a recently published procedure based on an unknown derivative of PGA.     

Human exposure to styrene

Summary In order to estimate the importance of skin resorption of styrene, as compared to pulmonary absorption, nine male volunteers were exposed for 10 to 30 min by dipping one hand in liquid styrene. Urine and breath were sampled periodically for metabolites (mandelic and phenylglyoxylic acids) and styrene analyses respectively. The results obtained show that the rate of absorption of styrene through the skin is very low, averaging 1 ± 0.5 g/cm² · min. This rate seems to be affected by the duration of exposure. In conclusion, this study shows that skin resorption plays only a minor role in most practical situations.