The molecular cause of germ cell meiotic defects in azoospermic men is rarely known. During meiotic prophase I, a proteinaceous structure called the synaptonemal complex (SC) appears along the pairing axis of homologous chromosomes and meiotic recombination takes place. Newly-developed immunofluorescence techniques for SC proteins (SCP1 and SCP3) and for a DNA mismatch repair protein (MLH1) present in late recombination nodules allow simultaneous analysis of synapsis, and of meiotic recombination, during the first meiotic prophase in spermatocytes. This immunofluorescent SC analysis enables accurate meiotic prophase substaging and the identification of asynaptic pachytene spermatocytes. Spermatogenic defects were examined in azoospermic men using immunofluorescent SC and MLH1 analysis. Five males with obstructive azoospermia, 18 males with nonobstructive azoospermia and 11 control males with normal spermatogenesis were recruited for the study. In males with obstructive azoospermia, the fidelity of chromosome pairing (determined by the percentage of cells with gaps [discontinuities]/splits [unpaired chromosome regions] in the SCs, and nonexchange SCs [bivalents with 0 MLH1 foci]) was similar to those in normal males. The recombination frequencies (determined by the mean number of MLH1 foci per cell at the pachytene stage) were significantly reduced in obstructive azoospermia compared to that in controls. In men with nonobstructive azoospermia, a marked heterogeneity in spermatogenesis was found: 45% had a complete absence of meiotic cells; 5% had germ cells arrested at the zygotene stage of meiotic prophase; the rest had impaired fidelity of chromosome synapsis and significantly reduced recombination in pachytene. In addition, significantly more cells were in the leptotene and zygotene meiotic prophase stages in nonobstructive azoospermic patients, compared to controls. Defects in chromosome pairing and decreased recombination during meiotic prophase may have led to spermatogenesis arrest and contributed in part to this unexplained infertility.    

1.
Baker SM, Plug AW, Prolla TA, Bronner CE, Harris AC, Yao X, et al: Involvement of mouse Mlh1 in DNA mismatch repair and meiotic crossing over. Nat Genet 13:336–342 (1996).
2.
Barlow AL, Hultén MA: Crossing over analysis at pachytene in man. Eur J Hum Genet 6:350–358 (1998).
3.
Dresser ME, Moses MJ: Silver staining of synaptonemal complexes in surface spreads for light and electron microscopy. Exp Cell Res 121:416–419 (1979).
4.
Dresser ME, Moses MJ: Synaptonemal complex karyotyping in spermatocytes of the Chinese hamster (Cricetulus griseus). IV. Light and electron microscopy of synapsis and nucleolar development by silver staining. Chromosoma 76:1–22 (1980).
5.
Egozcue J, Templado C, Vidal F, Navarro J, Morer-Fargas F, Marina S: Meiotic studies in a series of 1100 infertile and sterile males. Hum Genet 65:185–188 (1983).
6.
Eijpe M, Heyting C, Gross B, Jessberger R: Association of mammalian SMC1 and SMC3 proteins with meiotic chromosomes and synaptonemal complexes. J Cell Sci 113:673–682 (2000).
7.
Fletcher JM: Light microscope analysis of meiotic prophase chromosomes by silver staining. Chromosoma 72:241–248 (1979).
8.
Garcia M, Dietrich AJ, Freixa L, Vink AC, Ponsa M, Egozcue J: Development of the first meiotic prophase stages in human fetal oocytes observed by light and electron microscopy. Hum Genet 77:223–232 (1987).
9.
Gonsalves J, Sun F, Schlegal P, Hopps C, Turek P, Greene C, Martin RH, Reijo-Pera RA: Defective recombination in infertile men. Hum Mol Genet 13:2875–2883 (2004).
10.
Hassold T, Hunt P: To err (meiotically) is human: the genesis of human aneuploidy. Nat Rev Genet 2:280–291 (2001).
11.
Hassold T, Sherman S, Pettay D, Page D, Jacobs P: XY chromosome nondisjunction in man is associated with diminished recombination in the pseudoautosomal region. Am J Hum Genet 49:253–260 (1991).
12.
Hull MG, Glazener CM, Kelly NJ, Conway DI, Foster PA, Hinton RA, et al: Population study of causes, treatment, and outcome of infertility. Br Med J (Clin Res Ed) 291:1693–1697 (1985).
13.
Hultén M: Meiosis in XYY men. Lancet 1:717–718 (1970).
14.
Hultén M, Solari AJ, Skakkebaek NE: Abnormal synaptonemal complex in an oligochiasmatic man with spermatogenic arrest. Hereditas 78:105–116 (1974).
15.
Judis L, Chan ER, Schwartz S, Seftel A, Hassold T: Meiosis I arrest and azoospermia in an infertile male explained by failure of formation of a component of the synaptonemal complex. Fertil Steril 81:205–209 (2004).
16.
Koehler K, Hawley R, Sherman S, Hassold T: Recombination and nondisjunction in humans and flies. Hum Mol Genet 5:1495–1504 (1996).
17.
Lipkin SM, Moens PB, Wang V, Lenzi M, Shanmugarajah D, Gilgeous A, et al: Meiotic arrest and aneuploidy in MLH3-deficient mice. Nat Genet 31:385–390 (2002).
18.
Lynn A, Koehler KE, Judis L, Chan ER, Cherry JP, Schwartz S, et al: Covariation of synaptonemal complex length and mammalian meiotic exchange rates. Science 296:2222–2225 (2002).
19.
Marcon E, Moens P: MLH1p and MLH3p localize to precociously induced chiasmata of okadaic-acid-treated mouse spermatocytes. Genetics 165:2283–2287 (2003).
20.
Martin RH, Greene C, Rademaker A, Ko E, Chernos J: Analysis of aneuploidy in spermatozoa from testicular biopsies from men with nonobstructive azoospermia. J Androl 24:100–103 (2003a).
21.
Martin RH, Rademaker AW, Greene C, Ko E, Hoang T, Barclay L, Chernos J: A comparison of the frequency of sperm chromosome abnormalities in men with mild, moderate, and severe oligozoospermia. Biol Reprod 69:535–539 (2003b).
22.
Mittwoch U, Mahadevaiah SK: Unpaired chromosomes at meiosis: cause or effect of gametogenic insufficiency? Cytogenet Cell Genet 59:274–279 (1992).
23.
Moses M: Synaptonemal complex. Annu Rev Genet 2:363–412 (1968).
24.
Navarro J, Vidal F, Benet J, Templado C, Marina S, Egozcue J: XY-trivalent association and synaptic anomalies in a male carrier of a Robertsonian t(13;14) translocation. Hum Reprod 6:376–381 (1991).
25.
Peters AH, Plug AW, van Vugt MJ, de Boer P: A drying-down technique for the spreading of mammalian meiocytes from the male and female germline. Chromosome Res 5:66–68 (1997).
26.
Sarrate Z, Blanco J, Egozcue S, Vidal F, Egozcue J: Identification of meiotic anomalies with multiplex fluorescence in situ hybridization: Preliminary results. Fertil Steril 82:712–717 (2004).
27.
Schalk JA, Dietrich AJ, Vink AC, Offenberg HH, van Aalderen M, Heyting C: Localization of SCP2 and SCP3 protein molecules within synaptonemal complexes of the rat. Chromosoma 107:540–548 (1998).
28.
Shi Q, Spriggs E, Field L, Ko E, Barclay L, Martin R: Single sperm typing demonstrates that reduced recombination is associated with the production of aneuploid 24,XY human sperm. Am J Med Genet 99:34–38 (2001).
29.
Silber SJ: Intracytoplasmic sperm injection today: a personal review. Hum Reprod 13, Suppl 1:208–218 (1998).
30.
Sun F, Kozak G, Scott S, Trpkov K, Ko E, Mikhaail-Philips M, et al: Meiotic defects in a man with non-obstructive azoospermia: Case report. Hum Reprod 19:1770–1773 (2004a).
31.
Sun F, Oliver-Bonet M, Liehr T, Starke H, Ko E, Rademaker A, et al: Human male recombination maps for individual chromosomes. Am J Hum Genet 74:521–531 (2004b).
32.
Sun F, Trpkov K, Rademaker A, Ko E, Barclay L, Mikhaail-Philips M, Martin RH: The effect of cold storage on recombination frequencies in human male testicular cells. Cytogenet Genome Res 106:39–42 (2004c).
33.
Sun F, Trpkov K, Rademaker A, Ko E, Martin RH: Variation in meiotic recombination frequencies among human males. Hum Genet 116:172–178 (2005).
© 2005 S. Karger AG, Basel
2005
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.