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用双色荧光原位杂交检测人精子染色体非整倍体率
http://www.100md.com 《中华医学遗传学杂志》 1999年第2期
     作者:郑履康 刘胜勤 邓丽霞 张桥

    单位:郑履康 刘胜勤 邓丽霞 张桥(510089 广州,中山医科大学公共卫生学院遗传毒理研究室)

    关键词:双色荧光原位杂交;人精子染色体;非整倍体率

    中华医学遗传学杂志990216 【摘要】 目的 检测人精子染色体非整倍体率。方法 采用双色荧光原位杂交(FISH)方法,取少量精标本经洗后制片,用二硫苏糖醇(DTT)和二碘水杨酸锂(LIS)处理,使精子头部染色质去凝集。然后,与生物素标记的α卫星X染色体特异DNA探针(DXZ1)和地高辛标记的α卫星Y染色体特异DNA探针(DYZ3)进行原位杂交。用CY3-链亲和素、山羊抗链亲和素检测X染色体探针杂交信号;用鼠抗地高辛抗体、与荧光素结合的兔抗鼠抗体检测Y染色体探针杂交信号。结果 在Nikon荧光显微镜下可以清楚看到精子头部的杂交信号,头部有1个红色荧光杂交信号的精子为X染色体精子(X精子),有1个绿色荧光杂交信号的精子为Y染色体精子(Y精子)。精子头部有2个荧光杂交信号的精子为染色体数目异常精子。若用1条常染色体探针和1条性染色体探针进行FISH,可以区别头部有2个相同颜色荧光杂交信号的精子属非整倍体精子或二倍体精子。结论 双色荧光原位杂交(FISH)方法,可以用于测定接触致突变剂和非整倍体诱导剂后,人精子染色体非整倍体率的变化。
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    Using the method of two color fluorescence in

    situ hybridization to detect aneuploidy of human sperms

    ZHENG Lukang*, LIU Shengqin, DENG Lixia, ZHANG Qiao

    *Laboratory of Genetic Toxicology, Sun Yat-Sen University of Medical Sciences,Guangzhou 510089 P.R.China E-mail:zhenglk @ gzsums.edu.cn

    【Abstract】 Objective To develop the method of two color fluorescence in situ hybridization(FISH) assay and use it for detecting the aneuploidy frequency of human sperm chromosome. Methods Sperm sample was washed three times and the slides were prepared. The sperm heads were decondensed with dithiothreitol(DTT) and lithium diiodosalicylate(LIS). Then,the sperm nuclei were hybridized with biotin labeled alpha satellite X chromosome DNA probe (DXZ1) and digoxigenin labeled alpha satellite Y chromosome DNA probe (DYZ3). The hybridization signals were detected with CY3-Streptavidin, goat antistrepavidin for biotin labeled probe and with mouse antidigoxigenin, rabbit antimouse-FITC for digoxigenin labeled probe.Results Under the Nikon fluorescence microscope, the hybridization signals in the sperm heads were clearly visible. The sperm with one red hybridization singal was X chromosome sperm (X sperm),and the sperm with one green hybridization signal in the sperm head was Y chromosome sperm (Y sperm). In the case of two hybridization signals in one sperm head, the sperm should be a numerical abnormal one. By using two color FISH with one euchromosome probe and one sex chromosome probe, the sperm with same color of two hybridization signals in one sperm head could be identified as aneuploidy sperm or diploid sperm. Conclusion The two color FISH assay may be used to detect the aneuploidy frequency of human sperms that were exposed to mutagents and environmental potential aneuoploidogenic agents.
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    【Key words】 Two color fluorescence in situ hybridization Human sperm chromosome

    Frequency of aneuploidy

    染色体非整倍体与流产、畸形、儿童智力低下以及肿瘤的发生均有关系。非整倍体多发生于生殖细胞减数分裂过程,故研究人类配子染色体非整倍体是当今的一个热点。近年国外应用荧光原位杂交技术,用染色体特异DNA探针与人精子间期核DNA杂交,测定精子染色体非整倍体,是一种简便快速的方法。已用于测定正常人、不育者、染色体平衡易位携带者及接触化疗药物和工业化学物后,人精子染色体非整倍率[1-3]。我们实验室在先前建立单色荧光原位杂交方法的基础上[4],进一步采用了双色荧光原位杂交方法。该法可用于检测接触某些环境化学物后,人精子染色体非整倍率的改变,现报告如下。
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    1 材料与方法

    1.1 精子标本准备 按Martin等[1]和Williams等[5]法制片及杂交前处理。取新鲜或冷冻精液0.3ml,加5ml精子洗涤液(150mmol/L NaCl,10mmol/L Tris溶液pH8.0),2 000r/min,离心8分钟;共洗3次,最后约留0.05ml细胞,将细胞配至适当浓度制片(在高倍镜下,以精子不重叠为宜)。老化至少1天,玻片标本用二硫苏糖醇〔dithiothreitol(DTT), 10mmol/L,用100mmol/L Tris配pH8.0〕处理30分钟,然后用二碘水杨酸锂〔lithium diiodosalicylate (LIS), 10mmol/L, DTT 1mmol/L,用100mmol/L Tris配pH8.0〕处理3小时,取出用2SSC洗1次,晾干待用。

    1.2 探针 (1)生物素标记α卫星X染色体特异DNA探针〔alpha satellite chromosome X specific DNA probe, biotin labeled, (DXZ1) Oncor〕;(2)地高辛标记α卫星Y染色体特异DNA探针〔alpha satellite chromosome Y specific DNA probe, digoxigenin labeled,(DYZ3) Oncor〕。取0.5μl X探针和0.5μl Y探针加于9μl杂交混合液中(含55%甲酰胺,10%硫酸葡聚糖,鲑鱼精子0.05μg/μl)。
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    1.3 原位杂交 (1)将精子标本置70%甲酰胺中,70℃处理2分钟,取出立即置-20℃的70%,80%,95%乙醇中各2分钟脱水。(2)将含探针的杂交混合液置70℃水浴中变性5分钟,取出立即置冰水中至少10分钟。(3)取10μl探针杂交混合液加于已变性的精子标本上,盖上盖玻片,用橡胶胶水(rubber cement)封紧,将玻片放入已预温的塑料湿盒中,于37℃杂交过夜(16~18小时)。

    1.4 杂交后冲洗及信号检测 准备3缸50%甲酰胺溶液,2缸2SSC溶液。从湿盒取出玻片,除去盖玻片(将玻片浸入50%甲酰胺中,取出保持水平位数秒,再浸入甲酰胺中,轻摇,盖玻片可脱落),玻片依次置50%甲酰胺中,45℃洗3次,每次5分钟,2SSC溶液,37℃洗2次,每次4分钟,将未杂交上的探针洗去,然后置磷酸缓冲洗液(0.1mol/L Na2HPO4, 0.1mol/L NaH2PO4, 0.1%Nonidet P-40, pH8.0 PBD)中数分钟。杂交信号检测:从PBD液中取出玻片滴加阻断剂溶液(0.5%阻断剂blocking reagent, Boehringer Mannheim,用PBD配,pH8.0)15μl,盖上蜡片,37℃,10分钟,用PBD洗3次每次2分钟,用滤纸吸去多余液体(此后在较暗光线下操作,并保持标本不干)。于精子标本上依次加下列检测液,盖上蜡片,于37℃保温30分钟:(1)Cy3-链亲和素(10μg/ml,Cy3-Streptavidin, Amersham)与鼠抗地高辛抗体(1∶200,mouse anti-digoxigenin, Sigma)等量混合液10μl;(2)生物素化山羊抗链亲和素抗体(10μg/ml, biotinylated goat anti-streptavidin, Vector)与荧光素结合的兔抗鼠抗体(1∶200 rabbit anti mouse-FITC, Sigma)等量混合液10μl;(3)Cy3-链亲和素(10μg/ml)与荧光素结合的山羊抗兔抗体(1∶200,goat anti rabbit-FITC,Sigma)等量混合液10μl。
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    每次保温30分钟后,玻片用PBD洗3次,每次3分钟。后用联咪二苯吲哚(DAPI 0.5μg/ml)10μl复染,37℃,10分钟,PBD洗3次,每次2分钟,加8.5μl抗褪色液[2.3% 1,4 diazabicyclo (2,2,2)octane DABCO,甘油配],盖上盖玻片,指甲油封片,4℃保存。

    1.5 杂交信号观察 精子标本在Nikon荧光显微镜油镜下观察(使用DAPI/FITC/Texas Red滤色块)。

    2 结果及讨论

    在荧光显微镜下可见精子头部经DAPI复染后呈蓝色荧光,边缘清楚。在蓝色的精子头部有红色杂交信号者为X染色体精子(X精子);有绿色杂交信号者为Y染色体精子(Y精子),见图1。精子头部有一个荧光杂交信号为正常单倍体精子(X或Y精子图1A),有两个荧光杂交信号(二红,二绿,或一红一绿)为染色体异常精子,见图1B。
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    图1 双色荧光原位杂交结果 A:正常精子(精子头部有1个红色荧光信号者为X精子,有1个绿色荧光信号者为Y精子);B:染色体数目异常精子(两个绿色荧光信号同在1个精子核内,可为Y双体精子或二倍体精子,若用1条常染色体探针和1条性染色体探针进行双色荧光原位杂交,可以区别该精子属Y双体精子或二倍体精子)

    Fig 1 The results of two color FISH A:Normal sperms(a sperm nucleus with a red fluorescence domain was X sperm, and with a green fluorescence domian was Y sperm);B:Numeric chromosome abnormal sperm (two green fluorescence domains within the same sperm nucleus which may be classified in Y disomic sperm or diploidy sperm, in the case of hybridization with two probes, one euchromosome specific and the other sex chromosome specific, this sperm could be discriminated as disomic or diploidy sperm)
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    由于每个精子只有1条性染色体,故用两条性染色体探针(X,Y探针)进行的FISH,尚难区别精子头部有2个相同颜色荧光杂交信号的精子属超单倍体精子或二倍体精子。但若用1条常染色体探针和1条性染色体(X或Y)探针进行FISH,则可区别。此时,每个精子均有常染色体的荧光杂交信号,有一半精子有性染色体荧光杂交信号。如精子头部有3个荧光杂交信号,则为非整倍体精子,如有4个荧光杂交信号(二红二绿),则为二倍体精子。

    做好双色FISH的要点有两个,一是精子头部的去凝集。精子核染色质紧密凝集,探针不易进入,我们用DTT和LIS处理精子使精子头部胀大,探针易于进入。二是杂交信号荧光强度强,背景清晰,这样才能计数正确。本实验选择荧光强度较得克萨斯红大一倍的Cy3-链亲和素检测生物素探针的杂交信号[6],选荧光素结合的抗体检测地高辛探针的杂交信号,经过荧光强度加强后获得好的结果,在显微镜下,荧光强度强,背景清楚。

    目前已经有人用FISH技术检测苯作业工人淋巴细胞染色体非整倍体率[3];以及化疗前后肿瘤患者精子染色体非整倍率的改变[2]。国内尚在起步中,郑履康等[7]曾用单色FISH法测定接触二硫化碳男工精子X染色体非整倍体率。双色荧光原位杂交方法,可以用于接触环境致突变剂、非整倍体诱导剂后,对人生殖细胞遗传损伤的监测。此项工作我们正在进行。
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    本课题由国家自然科学基金(39470608)资助

    参考文献

    [1] Martin RH, Spriggs E, Rademaker AW. Multicolor fluorescence in situ hybridization analysis of aneuploidy and diploidy frequenceis in 225846 sperm from 10 normal men, Biol Reprod, 1996, 54(2)∶394-309.

    [2] Robbins WA. Cytogenetic damage measured in human sperm following cancer chemotherapy. Mutat Res, 1996, 355(1-2)∶235-252.

    [3] Zhang LP, Rothman N, Wang YX, et al. Interphase cytogenetics of workers exposed to benzene. Environ Health Persp, 1996, 104 Suppl 6∶1325-1329.
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    [4] 郑履康,邓丽霞,张桥.用荧光原位杂交检测人精子染色体非整倍体方法的建立.卫生毒理学杂志,1997,11(3)∶187-188.

    [5] Williams BJ, Ballenger CA, Malter HE, et al, Non-disjunction in human sperm:results of fluorescence in situ hybridization studies using two and three probes. Hum Mol Genet, 1993, 2(11)∶1929-1936.

    [6] Yurov YB, Soloviev IV, Vorsanova SG, et al. High resolution multicolor fluorescence in situ hybridization using cyanine and fluorescein dyes:rapid chromosome identification by directly fluorescently labeled alphoid DNA probes. Hum Genet, 1996, 97(3)∶390-398.

    [7] 郑履康,邓丽霞,张桥.CS2作业工人的精子X染色体非整倍率.中华劳动卫生职业病杂志,1998,16(4)∶197-200.

    (收稿:1998-05-20 修回:1998-09-16), http://www.100md.com