大蒜油对正己烷染毒小鼠毒性拮抗作用

目的探讨大蒜油减少小鼠正己烷活性代谢产物的生成作用,为减少正己烷中毒提供实验依据。方法健康成年昆明小鼠,随机分为正己烷染毒组和大蒜油干预组,分别灌胃给予正己烷和大蒜油+正己烷,取血,分离血清经乙酸乙酯萃取后,气相色谱法测定血清中2,5-己二酮(2,5-HD)含量。结果小鼠经正己烷单次灌胃染毒后测定血清2,5-HD含量为(0.14±0.14)μg/mL,10 h后达峰值(24.63±3.52)μg/mL,至染毒后20 h降至(0.02±0.04)μg/mL;正己烷染毒前后给予大蒜油使小鼠6h血清2,5-HD含量分别较单纯染毒组降低32.1%(P<0.01)、24.4%(P<0.05);提前给予大蒜油使小鼠4～14 h含量降低26%～54%不等,其中染毒后4、6、8、10 h与单纯染毒组比较,差异有统计学意义(P<0.05或P<0.01),但大蒜油并未改变正己烷染毒小鼠2,5-HD含量曲线的形状和达峰时间。结论大蒜油可抑制正己烷染毒小鼠2,5-HD的产生,降低血清2,5-HD水平,降低正己烷毒性。     

大蒜油及大鼠周龄和性别对正己烷体内代谢的影响

目的 探讨大蒜油及周龄、性别对正己烷在大鼠体内代谢的影响.方法 以Wistar大鼠为实验动物,(1)灌胃染毒:正己烷组(3000 mg/kg正己烷),大蒜油干预组(染毒前1 h予80 mg/kg大蒜油灌胃),8、12、16、20、24、28、32 h断尾取血.(2)腹腔注射染毒:正己烷组(1000 mg/kg正己烷),大蒜油干预组(染毒药前1 h予80 mg/kg大蒜油灌胃),8、12、16、20、24、28 h断尾取血.(3)6、8、10周龄(均为7只)雄性大鼠予正己烷3000 mg/kg灌胃,染毒后16、20、24 h断尾取血.(4)8周龄大鼠雌、雄各7只,予正己烷3000 mg/kg灌胃,染毒后16、20、24、28 h断尾取血.气相色谱法测定血清中2,5-己二酮浓度,比较给和不给大蒜油、不同周龄、不同性别大鼠血清中2,5-己二酮浓度.结果 (1)灌胃染毒:正己烷组、大蒜油干预组血清中2,5-己二酮浓度分别在20和24 h达到峰值,分别为19.2和12.3μg/ml,在峰值及之前时间点大蒜油干预组血清中2,5-己二酮浓度明显降低,但峰值后的消除过程明显减缓.(2)腹腔注射染毒:大蒜油对血清中2,5-己二酮浓度的影响与正己烷灌胃途径基本相同,两组分别在12和16 h达到峰值,分别为15.0和6.7 μg/ml.(3)周龄:16 h时6、8、10周龄大鼠血清中2,5-己二酮浓度分别为25.5、15.0、12.8μg/ml,8、10周龄与6周龄的差异有统计学意义(P＜0.05或P＜0.01);20 h时6、8、10周龄大鼠血清中2,5-己二酮浓度分别为24.7、18.3、15.0 μg/ml,10周龄与6周龄的差异有统计学意义(P＜0.05);24 h时6、8、10周龄大鼠血清中2,5-己二酮浓度分别为11.0、14.7、8.1 μg/ml,10周龄与8周龄的差异有统计学意义(P＜0.05).(4)性别:16 h时雄性、雌性大鼠血清中2,5-己二酮浓度分别为22.5、17.2 μg/ml,差异有统计学意义(P＜0.05);在20、24、28 h雄性、雌性大鼠血清中2,5-己二酮浓度分别为27.6、22.9μg/ml,24.6、19.1 μg/ml,19.1、13.8μg/ml,不同性别间的差异均无统计学意义(P＞0.05).结论 大蒜油可明显减少正己烷在大鼠体内代谢物2,5-己二酮的生成量;低周龄的动物正己烷的代谢能力高于高周龄的动物.

Abstract：

Objective To investigate effects of garlic oil (GO),age and sex on n-hexane metabolism in rats. Methods The Wistar rats were used as experimental animals. (1) Intragastric administration: nhexane group (3000 mg/kg n-hexane),GO treated group (80 mg/kg GO ig. an hour earlier than 3000 mg/kg n-hexane), then blood was taken from tails of rats at 8, 12, 16, 20, 24, 28, 32 h points after n-hexane administration. (2)Intraperitoneal injection: n-hexane group ( 1000 mg/kg n-hexane), GO treated group (80 mg/kg GO ig. an hour earlier than 1000 mg/kg n-hexane), then took blood was taken from tails of rats at 8, 12,16, 20, 24, 28 h points after n-hexane injection. (3) 7 rats each group of 6, 8, 10 weeks age were administrated by 3000 mg/kg n-hexane intragastrically, then were taken blood from tails at 16, 20, 24 h points after administration.(4) 7 male and 7 female rats of 8 weeks age were administrated by 3000 mg/kg n-hexane intragastrically, then were taken blood from tails at 16, 20, 24, 28 h points after administration. The gas chromatography was used to determine the metabolite 2, 5-hexanedione concentration of n-hexane in serum and 2, 5-hexanedione concentration was compared between GO and no GO treated rats, different ages and different sexes. Results ( 1 )Intragastric administration: 2, 5-hexanedione concentrations in serum of n-hexane group and GO treated group had the peak 19.2 and 12.3 μg/ml at 20 h and 24 h points. Compared with nhexane group, the serum 2, 5-hexanedione concentration of GO treated group was lower at time points prior to peak and 2, 5-hexanedione eliminating process was slower after peak. (2) Intraperitoneal injection: effects of GO on the serum 2, 5-hexanedione concentrations was very similar to intragastric administration, 2, 5-hexanedione concentrations in serum of n-hexane group and GO treated group had the peak 15.0 and 6.7μg/ml at 12 h and 16 h points.(3) Comparison of the serum 2, 5-hexanedione concentrations of different weeks age rats: The serum 2, 5-hexanedione concentrations of 6, 8, 10 weeks age rats were 25.5, 15.0, 12.8μg/ml each (8, 10 weeks age significantly lower than 6 weeks age) at 16 h point; at 20 h point, they were 24.7, 18.3, 15.0 μg/ml each ( 10 weeks age significantly lower than 6 weeks age); at 24 h point, they were 11.0, 14.7, 8.1 μg/ml each (10 weeks age significantly lower than 8 weeks age). (4) Comparisons of the serum 2, 5-hexanedione concentrations of different sex rats: the serum 2, 5-hexanedione concentrations of male and female rats were 22.5, 17.2 μg/ml each at 16 h point (different significantly); at 20, 24, 28 hpoints, they were 27.6, 22.9 μg/ml, 24.6,19.1 μg/ml, 19.1, 13.8 μg/ml each (different non-significantly).Conclusion GO reduces production of 2, 5-hexanedione in serum generated by n-hexane in rats; the metabolic capacity of low age rats on n-hexane is stronger than high age ones.     

大蒜油拮抗2,5-己二酮对大鼠神经组织的氧化损伤的效果

目的 探讨大蒜油对2,5-己二酮(2,5-hexanedione,2,5-HD)导致的大鼠神经组织氧化损伤的拮抗作用和对周围运动神经毒性的影响.方法 Wistar雄性大鼠40只,随机分为正常对照组、模型组、人蒜油低、高剂量组,每组10只.模型组及大蒜油低、高剂量组分别给予2,5-HD 300ms/ks腹腔注射,正常对照组给予生理盐水,5次/周,持续6周.大蒜油低、高剂量组提前1周分别给予40和80mg/kg大蒜油灌胃,持续至实验结束.测定后肢撑力指数和平衡指数等神经行为学指标,实验结束取脑、脊髓和坐骨神经分别测定丙二醛(MDA)、还原型谷胱廿肽(CSH)含量、总抗氧化能力(T-AOC)和抑制羟自由基能力.结果 与第0周比较,后肢撑力指数第4周模型组升高44%,大蒜油低剂量组升高50%,大蒜油高剂量组升高49%,但3组间差异无统计学意义(P>0.05);第4周模型组平衡指数降低30%,大蒜油低剂量组降低45%,大蒜油高剂量组降低68%,与模型组相比,差异有统计学意义(P<0.01).大蒜油低、高剂基组大鼠在第4周即出现运动异常,较模型组人鼠提前1周;各组步态评分,模型组,大蒜油低、高剂量组均明显高于对照组,且大蒜油高剂量组高于模型组,差异均有统计学意义(P<0.05).在大脑、脊髓和坐骨神经中,与正常对照组相比,模型组人鼠MDA含量升高,抑制羟自由基能力降低,差异均有统计学意义(P<0.05或P<0.01);与模型组比较,大蒜油低、高剂量组在各神经组织中MDA含量均明显降低,抑制羟自由基能力明显升高,差异均有统计学意义(P<0.01).结论 大蒜油可拮抗2,5-HD所致的大鼠神经组织氧化损伤,但并末改善2,5-HD导致的周围运动神经损伤,提示氧化-抗氧化损伤不是2,5-HD中毒性神经病的主要机制.     

2,5-己二酮对小鼠视网膜损伤的实验研究

目的 研究2,5-己二酮(2,5-HD)对小鼠视网膜组织形态学的影响及对视网膜组织的脂质过氧化作用,揭示正己烷对视网膜损伤的发病机制.方法 48只昆明种小鼠随机分为空白对照组、阴性对照组和2,5-HD染毒组.空白对照组12只,不做任何处理;阴性对照组12只,腹腔注射生理盐水;2,5-HD染毒组24只(分为2、4和8周染毒组),腹腔注射质量分数为2.5％的2,5-H-HD溶液,剂量为400 mg/kg,每日给药1次.光学显微镜下观察2,5-HD对视网膜组织的病理形态学影响;并且测定视网膜组织匀浆中超氧化物歧化酶(SOD)活力及丙二醛(MDA)含量.结果 空白对照及阴性对照组小鼠视网膜结构正常.2,5-HD染毒8周组光感受器内外节分界不清,排列疏松紊乱;外丛状层呈疏松网状结构,染色不均;神经节细胞层可见胞核深染固缩坏死.随着2,5-HD染毒时间的延长,SOD活力逐渐降低,MDA含量增加,组间比较差异有统计学意义(P＜0.05).结论 2,5-HD可造成小鼠视网膜组织损伤,脂质过氧化作用是致视网膜损伤的机制之一.     

盐酸戊乙奎醚治疗百草枯急性肺损伤的实验研究

目的 研究盐酸戊乙奎醚注射液(长托宁)对百草枯(PQ)急性肺损伤的干预作用及其机制.方法 选取80只健康成年雄性Wistar大鼠随机分为对照组(10只)、100 mg/kg PQ染毒组(10只)、100 mg/kg PQ染毒+33 μg/kg长托宁治疗组(30只)、100 mg/kg PQ染毒+66μg/kg长托宁治疗组(30只).2个治疗组分别于给药后的36、72 h及7 d处死.HE染色行肺组织病理学检查.取肺组织检测基质金属蛋白酶-2(MMP-2)、小窝蛋白-1、羟脯氨酸(HYP),取血清、支气管肺泡灌洗液(BALF)进行内皮素(ET)的检测.结果 病理学检查证实大鼠急性肺损伤模型复制成功.染毒组大鼠肺组织中MMP-2、HYP及血清、BALF中ET含量分别为(1.77±0.40)μg/g、(2.91±0.79)μg/g、(505.23±124.69)μg/ml、(640.38±136.60)μg/ml,均高于对照组[分别为(0.95±0.66)μg/g、(1.48±0.69)μg/g、(95.48±46.01)μg/ml、(200.40±88.39)μg/ml]差异均有统计学意义(P<0.05);长托宁治疗组的上述各指标均较染毒组下降,差异亦有统计学意义(P<0.05).染毒组大鼠肺组织中小窝蛋白-1含量为(1.77±0.82)μg/g,明显低于对照组[(5.39±1.68)μg/g],差异有统计学意义(P<0.05);长托宁治疗组的小窝蛋白-1含量均高于染毒组,差异有统计学意义(P<0.05).结论 长托宁可降低PQ染毒大鼠肺组织MMP-2、HYP以及血清和BALF中ET的含量,提高小窝蛋白-1的含量,进一步减轻百草枯所致的肺损伤.     

CYP2E1在大蒜油拮抗正己烷神经损伤中的作用

目的 研究CYP2E1在大蒜油(garlic oil,GO)阻止正己烷(n-hexane)致大鼠周围神经损伤的作用及其机制.方法 雄性Wistar大鼠50只,随机分为正常对照组、GO对照组、正己烷模型组、GO低剂量加正己烷组和高剂量加正己烷组(n=10).模型组及GO低、高剂量组大鼠分别给予2000 mg/kg正己烷灌胃;GO低、高剂量组大鼠在正己烷灌胃前1h分别给予40、80 mg/kg GO灌胃,GO对照组给予80 mg/kg,每周6次,持续10周.每2周测步态评分,监测大鼠周围神经损伤情况.于第10周末,断头处死大鼠,检测肝组织中CYP2E1表达及活力的改变,以及血清中2,5-己二酮(2,5-HD)含量的变化.结果 与正常对照组相比,GO对照组大鼠肝脏中CYP2E1含量及活力分别下降83.1％和48.3％,且差异均有统计学意义(P＜0.01);与正常对照组相比,模型组大鼠肝脏中CYP2E1含量及活力分别升高122.5％和72.2％,且差异均有统计学意义(P＜0.01);与模型组相比,GO低、高剂量组大鼠肝脏中CYP2E1含量分别降低32.9％和39.1％,且CYP2E1活力分别降低27.4％和44.5％,差异均有统计学意义(P＜0.01);与模型组相比,GO低、高剂量组大鼠血清中2,5-HD含量分别下降47.7％和78.7％,且差异均有统计学意义(P＜0.01).各组步态评分显示,模型组及GO低、高剂量组均明显高于对照组,但GO低、高剂量组低于模型组,差异有统计学意义(P＜0.05).结论 GO能够有效拮抗正己烷的外周神经损伤,其机制可能与肝脏中CYP2E1含量及活力降低,使正己烷代谢为2,5-HD减少有关.     

小鼠血清中2,5-己二酮含量的气相色谱测定

目的 建立小鼠血清中2,5-己二酮(2,5-HD)的气相色谱测定方法.方法 取小鼠血清0.3 ml加0.03 g无水K2CO3,加入乙酸乙酯1.2 ml萃取30 min后,进行气相色谱测定.结果 血清中没有杂质干扰2,5-HD的测定,方法最低检出浓度为0.03 μg/ml,线性范围0.03～80.00μg/ml;回收率83.8%～99.9%;日内相对标准偏差(RSD)3.3%～5.2%,日间(RSD)3.3%～8.0%.结论 本方法准确可靠,具有良好的重现性,可用于小鼠血清中2,5-HD含量的测定.     

温室土壤有机提取物对小鼠肝肾功能的影响

目的研究温室土壤中有机提取物(extractable organic matter,EOM)对小鼠肝肾功能的影响。方法于2010年5月采集并提取某蔬菜大棚土壤中的EOM。将40只健康10周龄清洁级昆明雄性小鼠随机分为4组,分别为对照(DMSO-植物油体积比为6︰4)组和低剂量(0.5 g/ml)、中剂量(1.5 g/ml)和高剂量(3 g/ml)EOM染毒组,每组10只。采用灌胃方式连续染毒4周。检测肝、肾组织匀浆和血清中的超氧化物歧化酶(SOD)活力与丙二醛(MDA)含量以及肝肾功能相关生化指标[丙氨酸氨基转移酶(ALT)和天门冬氨酸氨基转移酶(AST)、碱性磷酸酶(ALP)的活力和总蛋白(TP)、白蛋白(ALB)、球蛋白(GLO)、总胆固醇(TCH)、甘油三酯(TG)、肌酐(cr)、尿素氮(BUN)、尿酸(UA)、血糖(GLU)含量的测定,并计算ALT/AST、白蛋白/球蛋白(A/G)值。结果与对照组比较,1.5、3.0 g/ml EOM染毒组小鼠肝、肾匀浆中SOD活力均下降,MDA含量均升高;各剂量EOM染毒组小鼠血清中仅MDA含量明显升高,差异有统计学意义(P<0.05或P<0.01)。且随着EOM染毒剂量的升高,小鼠肝、肾匀浆中SOD活力呈剂量依赖性下降(P<0.05),肝、肾匀浆和血清中MDA含量呈剂量依赖性上升(P<0.05)。与对照组比较,各剂量EOM染毒组小鼠血清中ALT活力及1.5、3.0 g/ml EOM染毒组小鼠血清中AST活力和cr、BUN含量以及1.5 g/ml EOM染毒组小鼠血清中ALP活力均明显升高,0.5、1.5 g/ml EOM染毒组小鼠血清中TG含量均明显下降,差异有统计学意义(P<0.05或P<0.01);此外,0.5 g/ml EOM染毒组小鼠血清中GLO含量明显升高,A/G值明显下降,差异有统计学意义(P<0.05);1.5、3.0 g/ml EOM染毒组小鼠血清中UA和3.0 g/mlEOM染毒组小鼠血清中GLU含量明显下降,差异有统计学意义(P<0.05);而各剂量EOM染毒组小鼠血清中TP、ALB、TCH含量及ALT/AST值均无显著变化。随着EOM染毒剂量的升高,小鼠血清中AST活力和BUN含量均呈剂量依赖性升高(P<0.05),GLU含量呈剂量依赖性下降(P<0.05);其他指标均未发现明显相关关系。结论温室土壤中EOM可诱导小鼠肝、肾组织产生脂质过氧化损伤作用。     

除草剂西玛津对小鼠的免疫毒性作用

目的 探讨均三氮苯类除草剂西玛津对小鼠的免疫毒性.方法 BALB/c小鼠30只,按体重随机分为5组,每组6只,分别为西玛津90、200、400 mg/k(g染毒剂量组(每日1次,连续21 d灌胃染毒),阴性对照组(予蒸馏水)和阳性对照组(腹腔注射20 mg/kg环磷酰胺).观察小鼠体重变化、脾脏和胸腺的脏器系数、脾脏T细胞转化增殖能力以及血清中白细胞介素(IL)-2、IL-4、IgG和IgM含量.结果 200与400 mg/kg染毒组小鼠体重、脾脏和胸腺脏器系数以及T细胞转化增殖能力均明显低于阴性对照组,差异均有统计学意义(P＜0.05或P＜0.01);200mg/kg染毒组小鼠血清中IL-2、IL-4、IgG和IgM含量分别为(108.50±3.20)pg/ml、(36.54±3.36)pg/ml、(46.25±7.41)μmg/ml、(17.58±2.23)μg/ml;400 mg/kg染毒组小鼠血清中IL-2、IL-4、IgG和IgM含量分别为(85.70±4.00)pg/ml、(35.92±2.29)pg/ml、(40.08±6.80)μg/ml、(11.92±3.23)μg/ml,均明显低于阴性对照组,差异均有统计学意义(P＜0.05或P＜0.01).结论 西玛津对小鼠细胞免疫和体液免疫功能均有抑制作用.     

2,5-己二酮诱导大鼠脊髓中神经丝含量变化的研究

目的 观察2,5-己二酮(2,5-HD)诱导大鼠脊髓中神经丝(NF)含量变化,以探讨正己烷中毒性神经病的分子机制.方法 雄性Wistar大鼠70只随机分为0、2、4、8周对照组和2、4、8周染毒组,每组10只.经腹腔注射2,5-DH予染毒组动物,剂量为400 mg/kg,建立正己烷中毒性神经病模型,对照组注射等量的盐水.利用步态评分评价大鼠周围神经病症状的进展,免疫印迹法(Western Blotting)检测脊髓组织高、中和低相对分子质量神经丝(NF-H、NF-M和NF-L)含量的变化.结果 HD染毒2周后,大鼠逐渐出现肌力降低、步态异常、瘫痪等表现,至染毒8周结束时大鼠呈现典型的中毒性周围神经病特征.随着2,5-HD染毒的进行,大鼠脊髓NF含量呈进行性下降.与0周对照组相比,2、4和8周染毒组大鼠脊髓上清中NF-H含最分别下降15.7%、57.0%和58.0%,NF-M含量分别下降36.0%、61.3%和65.2%,NF-L含量分别下降20.8%、43.9%和44.3%,差异均有统计学意义(P<0.01);在脊髓沉淀中,与0周对照组比较,染毒4、8周组NF-H含量分别下降35.6%和43.2%,NF-L含量分别下降26.4%和42.1%,差异均有统计学意义(P<0.01);2、4和8周染毒组大鼠脊髓沉淀中NF-M含量分别下降23.3%、33.9%和63.7%,差异有统计学意义(P<0.01).大鼠脊髓组织中NF-H、NF-M和NF-L含量与步态评分的复相关系数分别为0.8912,0.9282和0.8981,差异均有统计学意义(P<0.01).结论 2,5-HD染毒诱导的脊髓组织中NF亚单位含量下降,可能是正己烷神经毒性的机制之一.     

2,5-己二酮对大鼠运动及感觉神经元神经生长因子表达的影响

目的　研究正己烷的代谢产物2 ,5 己二酮对大鼠神经系统运动、感觉神经元内源性神经生长因子(NGF)表达的影响。方法　采用原代培养的大鼠背根神经节(DRG)感觉神经元和培养的大鼠脊髓前角运动神经元瘤细胞系VSC4 - 1细胞,用相差显微镜观察细胞形态,同时用免疫组化方法分析不同浓度2 ,5 HD(2 . 5、5 . 0、10 . 0、2 0 . 0mol L)染毒2 4小时后DRG、VSC4 1细胞内NGF含量的变化。结果　与对照组相比,2 ,5 己二酮染毒剂量为5 . 0、10 . 0、2 0 . 0mmol L时,皆可使DRG细胞及VSC4 1细胞NGF表达量显著下降(P <0 . 0 5 ) ;各剂量组间两两比较发现随着染毒剂量增高,两类细胞NGF表达水平的下降有愈为明显的趋势。结论　2 ,5 己二酮可降低大鼠DRG感觉神经元和脊髓前角运动神经元(VSC4 . 1细胞)、内源性NGF的表达水平,并进一步抑制了两类细胞的生长与存活。     

正已烷对人体血清中髓鞘碱性蛋白的影响

目的 了解正已烷接触对人体血清中髓鞘碱性蛋白(MBP)的影响.方法 选取正已烷接触1年以上的工人269名作为接触组,同时选取未接触正已烷的工人104名作为对照组,测定工人尿中2,5-已二酮的含量,并依据WS/T 243-2004<职业接触正己烷的生物限值>,将含量超出和未超出生物限值的工人分为高接触组和低接触组,使用酶联免疫吸附法测定工人血清中MBP水平.结果 接触组工人尿中2,5-己二酮含量均值为(3.10±1.35)mg/L,对照组尿中2,5-已二酮含量均小于最低检出限(0.5mg/L).低接触组和高接触组工人血清中MBP表达的水平分别为(1.62±0.23)和(2.43±0.24)μg/L,明显高于对照组[(0.78±0.12)μg/L],差异均有统计学意义(P<0.01).经双变量Pearson相关分析,血清中MBP表达水平与尿中2,5-已二酮的含量呈正相关(r=0.781,P<0.01).结论 正已烷接触可导致人体血清中MBP表达水平升高,血清中MBP可作为正已烷接触的效应标志物.

Abstract：

Objective To explore the effects of n-hexane on expression of serum myelin proteins (MBP) in workers occupationally exposed to n-hexane.Methods In this study,269 workers exposed to n-hexane for more than one year and 104 subjects not exposed to n-hexane served as the exposure group and the control group,respectively.The urinary 2,5-hexanedione levels in all subjects were detected.On the basis of urinary 2,5-hexanedione levels,the exposure group was divided into the high exposure sub-group and low exposure sub-group.The serum myelin basic protein (MBP) levels were measured by ELISA kit.Results The mean concentration of urinary 2,5-hexanedione in the exposed group was (3.10±1.35) mg/L,The concentration of urinary 2,5-hexanedione in the control group was undetectable.The levels of serum MBP in the high exposure sub-group and low exposure sub-group were (2.43±0.24) and (1.62 ±0.23) (μg/L,respectively,which were significantly higher than that (0.78±0.12) μg/L in the controls (P<0.01).Pearson correlation analysis showed the positive correlation between serum MBP levels and urinary 2,5-hexanedione levels (r =0.781,P<0.01).Conclusion The results of present study showed that the serum MBP levels of workers occupationally exposed to n-hexane significantly elevated,and the serum MBP can serve as the effective biomarker of n-hexane exposure.     

单唾液酸神经节苷脂对2,5-己二酮诱导的PC12细胞凋亡的影响

目的研究单唾液酸神经节苷脂(GM1)对2,5-己二酮(2,5-HD)诱导PC12细胞凋亡的保护作用,并探讨其作用机制。方法以PC12细胞为神经元的细胞模型,2,5-HD、GM1及磷脂酰肌醇3-激酶(PI3-K)抑制剂LY294002单独或联合处理细胞,MTT法检测细胞存活率,Giemsa染色法观察细胞形态,琼脂糖凝胶电泳检测DNA断裂,流式细胞术(FCM)检测细胞凋亡率,免疫印迹检测蛋白激酶B(Akt)和磷酸化-Akt(P-Akt)蛋白的表达。结果GM1可以有效地改善凋亡引起的细胞形态学改变,提高细胞存活率(P<0.05),最高可提高36.35%;降低DNA断裂程度,减少凋亡率(P<0.001),最明显可降低69.36%。GM1能够促进Akt磷酸化,LY294002可以阻断这种作用。结论GM1对2,5-HD诱导的PC12细胞凋亡有保护作用。该保护作用可能是通过启动PI3-K信号通路,激活Akt及其下游信号而产生的。     

Physiologically based modeling of n-hexane kinetics in humans following inhalation exposure at rest and under physical exertion: impact on free 2,5-hexanedione in urine and on n-hexane in alveolar air

We used a modified physiologically based pharmacokinetic (PBPK) to describe/predict n-hexane (HEX) alveolar air concentrations and free 2,5-HD urinary concentrations in humans exposed to n-HEX by inhalation during a typical workweek. The effect of an increase in workload intensity on these two exposure indicators was assessed and, using Monte Carlo simulation, the impact of biological variability was investigated. The model predicted HEX alveolar air concentrations at rest of 19.0 ppm (25 ppm exposure) and 38.7 ppm (50 ppm exposure) at the end of the last working day (day 5), while free 2,5-HD urinary concentrations of 3.4 micromol/L (25 ppm) and 6.3 micromol/L (50 ppm) were predicted for the same period (last 4.5 hours of Day 5). Monte Carlo simulations showed that the range of values expected to occur in a group of 1000 individuals exposed to 50 ppm of HEX (95% confidence interval) for free 2,5-HD (1.7-14.7 micromol/L) is much higher compared with alveolar air HEX (33.4-46 ppm). Simulations of exposure at 50 ppm with different workloads predicted that an increase in workload intensity would not greatly affect both indicators studied. However, the alveolar air HEX concentration is more sensitive to modifications of workload intensity and time of sampling, after the end of exposure, compared with 2,5-HD. The PBPK model successfully described the HEX alveolar air concentrations and free 2,5-HD urinary concentrations measured in human volunteers and is the first, to our knowledge, to describe the excretion kinetics of free 2,5-HD in humans over a 5-day period.     

Toxicokinetic study of pyrrole adducts and its potential application for biological monitoring of 2,5-hexanedione subacute exposure

Purpose

The formation of pyrrole adducts might be responsible for peripheral nerve injury caused by n-hexane, but there is not an effective biomarker for monitoring occupational exposure of n-hexane. The current study was designed to investigate the changes of pyrrole adducts in serum and urine of rats exposed to 2,5-hexanedione (2,5-HD) and analyze the correlation between pyrrole adducts and 2,5-HD.

Methods

Two groups of male Wistar rats (n = 8) were administered a single dose of 200 and 400 mg/kg 2,5-HD (i.p.), and another two groups (n = 8) were given daily dose of 200 and 400 mg/kg 2,5-HD (i.p.) for 5 days. Pyrrole adducts and 2,5-HD in serum and urine were determined, at different time points after dosing, using Ehrlich’s reagent and gas chromatography, respectively.

Results

The levels of pyrrole adducts in serum accumulated in a time-dependant manner after repeated exposure to 2,5-HD, while pyrrole adducts in urine, and 2,5-HD in serum and urine were kept stable. The half-life times (t _1/2) of 2,5-HD and pyrrole adducts in serum were 2.27 ± 0.28 and 25.3 ± 3.34 h, respectively. Furthermore, the levels of pyrrole adducts in urine were significantly correlated with the levels of 2,5-HD in serum (r = 0.736, P < 0.001) and urine (r = 0.730, P < 0.001), and the levels of pyrrole adducts in serum were correlated with the cumulative dosage of 2,5-HD (r = 0.965, P < 0.001).

Conclusion

The results suggested that pyrrole adducts in serum and urine might be markers of chronic exposure to n-hexane or 2,5-HD.     

肝脏中乙醇脱氢酶活力在大蒜油阻止大鼠正己烷神经损伤中的变化

目的 研究大蒜油(garlic oil,GO)对正己烷(n-hexane)所致大鼠周围神经损伤的保护作用及其机制.方法 雄性Wistar大鼠40只,随机分为正常对照组、模型组、大蒜油低剂量组和高剂量组(n=10);正常对照组动物给予等体积生理盐水灌胃,模型组和大蒜油低、高剂量组大鼠分别给予2000mg/kg正己烷灌胃,大蒜油低、高剂量组大鼠于正己烷灌胃前1 h分别给予40和80mg/kg大蒜油灌胃,每周6次,持续10周.每周测步态评分和转棒指数,监测大鼠周围神经损伤情况.10周末,断头处死大鼠,测定肝组织中乙醇脱氢酶(ADH)、丙二醛(MDA)、还原型谷胱甘肽(GSH)、谷胱甘肽过氧化物酶(GSH-Px)、总抗氧化能力(T-AOC)、抑制羟基自由基能力.结果 与正常对照组相比,模型组大鼠步态评分明显升高,差异有统计学意义(P＜0.01),而转棒指数明显下降.肝脏中ADH活力[(3.64±0.73)U/mgpro]上升49.8%,肝脏中GSH-Px、T-AOC和抑制羟基自由基能力水平下降[分别为(182.0±41.7)、(1.10±0.27)、(162.1±26.1)U/mg pro],MDA含量[(1.89±0.42)nmol/mg pro]上升,与正常对照组[分别为(2.43±0.54)U/mgpro、(273.3±48.8)U/mg pro、(1.89±0.42)U/mg pro、(196.3±36.9)U/mg pro、(1.28±0.28)nmol/mg pro]的差异均有统计学意义(P＜0.05或P＜0.01).与模型组相比,大蒜油低、高剂量组大鼠步态评分明显降低,差异有统计学意义(P＜0.05),而转棒指数明显升高,差异均有统计学意义(P＜0.05或P＜0.01);与正常对照组相比,肝脏中ADH活力分别降低了25.3%和86.0%,GSH-Px、GSH、T-AOC及抑制羟基自由基能力水平明显上升,MDA含量明显下降,差异均有统计学意义(P＜0.05或P＜0.01).结论 大蒜油能够有效拮抗正己烷诱导所致的外周神经损伤,其机制可能与肝脏ADH活力降低有关.