Sperm: Radiation-induced chromosome aberrations

Chromosome aberrations in sperm directly irradiated in vitro 


(Chromosome aberrations in human spermatozooa irradiated in vitro as visualized by IVF to hamster oocytes..     Sample picutes are courtesy of Dr. H. Tateno, Biological Sciences, Asahikawa Medical College)

Scenario

     To estimate the human genetic risk posed by induced chromosome aberrations, several approaches have been made, e.g., chromosome aberration in somatic cells as surrogates for the genetic effects in germ cells, modelling in the experimental animals such as translocation induction in spermatogonial stem cells.

     Recently it became possible to adopt more direct method to examine the chromosome aberrations in human sperm through inter-species in vitro fusion of human sperm with eggs from laboratory animals, such as mouse, Syrian hamster, etc. The chromosomal effects of radiotherapy on germ cells can be examined with this technology. The improvement of efficiency of the inter-species in vitro fertilization (IVF) is in progress because the efficiency of the IVF has been thought to influence the recovery of primary DNA damage into chromosome aberrations. In particular, during spermiogenesis (in epididymis), the DNA associated histone is replaced by –SS- rich protamine. And DNA damage is not repaired in the sperm until fertilization, where the DNA damage can be repaired by repair enzymes brought by egg. The unrepaired DNA damage is the subject to the chemical hydrolysis (storage effects). Recently, several experiments have shown that the method became relatively stable and consistent results were obtained for human spermatozoa by inter-species IVF. The sperm assay may call attention not only to the consequences of radiation exposure to sperm but also to the genome alterations incurred by radiation during meiotic process that are later inherited by sperm.

References 

Brandriff, B. F., Gordon, L. A., Ashworth, L. K. and Carraro, A. (1988): Chromosomal aberrations induced by in vitro irradiation: Comparison between sperm and lymphocytes. Environ. Mol. Mutagen., 12:167-177.
Genesca, A., Caballin, M R., Miro, R., Benet, J., Bonfill, X. and Egozcue, J. (1990): Human sperm chromosomes. Long-term effect of cancer treatment. Cancer Gecet. Cytogenet., 46:251-260.
Genesca, A., Barrios, L., Miro, R., Caballin, M. R., Benet, J., Bonfill, X. and Egozcue, J. (1990): Lymphocytes and sperm chromosome studies in cancer-treated men. Hum. Genet., 84:353-355.
Genesca, A., Benet, J., Caballin, M. R., Miro, R., Germa, J. R. and Egozcue, J. (1990): Significance of structural chromosome aberrations in human sperm. Hum. Genet., 85:495-499.
Kamiguchi, Y. and Tateno, H. (1987): X-ray-induced chromosome aberrations in human spermatozoa. In, Mohri, H. ed., “New Horizons in Sperm Cell Research”. Jpn. Sci. Soc. Press, Tokyo, pp.11-123.
Kamiguchi, Y., Tateno, H. and Mikamo, K. (1990): Dose-response relationship for the induction of structural chromosome aberrations in human spermatozoa after in vitro exposure to tritium β-rays. Mutation Res., 228:125-131.
Kamiguchi, Y., Tateno, H. and Mikamo, K. (1990): Types of structural chromosome aberrations and their incidences in human spermatozoa X-irradiated in vitro. Mutation Res., 228:133-140.
Kamiguchi, Y. and Mikamo, K. (1982): Dose-response relationship for induction of structural chromosome aberrations in Chinese hamster oocytes after X-irradiation. Mutation Res., 103:33-37.
Martin, R. H., Hildebrand, K., Yomamoto, J., Rademaker, A., Barnes, M., Douglas, G., Arthur, K., Ringrose, T. and Brown, I. S. (1986): An increased frequency of human sperm chromosomal abnormalities after radiotherapy. Mutation Res., 174:219-225.
Martin, R. H., Rademaker, A., Barnes, M., Arthur, K., Ringrose, T. and Douglas, G. (1985): A prospective serial study of the effects of radiotherapy on semen parameters and hamster egg preparation rates. Clin. Invest. Med., 8:239-243.
Martin, R. H., Hildebrand, K., Yamamoto, J., Rademaker, A., Barns, M., Douglas, G., Arthur, K., Ringrose, T. and Brown, I. S. (1986): A increased frequency of human sperm chromosomal abnormalities after radiotherapy. Mutation Res., 174:219-225.
Martin, R. H., Rademaker, A., Hildebrand, K., Barnes, M., Arthur, K., Ringrose, T., Brown, I. S. and Douglas, G. (1989): A comparison of chromosomal aberrations induced by in vivo radiotherapy in human sperm and lymphocytes. Mutation Res., 226:21-30.
Martin, R. H. (1988): Sperm chromosomal analysis after radiotherapy. Hum. Genet., 79:392-393.
Mikamo, K., Kamiguchi, Y. and Tateno, H. (1990): Spontaneous and in vitro radiation-induced chromosome aberrations in human spermatozoa: Application of a new method. Mutation and Environment, Part B, 447-456.
Tateno, H., Kamiguchi, Y., Shimada, M. and Mikamo, K. (1989): Cytogenetic effects of X- and γ-rays on spermatozoa of the Chinese hamster. J. Radiat. Res., 30:95.
Tateno, H., Kamiguchi, Y., Watanabe, S., Mikamo, K. and Sawada, S. (1996): Relative biological effectiveness (RBE) of 252Cf fission neutrons for the induction of chromosome damage in human spermatozoa. Int. J. Radiat. Biol., 70:229-235.
Tateno, H., Kamiguchi, Y., Shimada, M. and Mikamo, K. (1996): Difference in types of radiation-induced structural chromosome aberrations and their incidences between Chinese and Syrian hamster spermatozoa. Mutation Res., 350:339-348. 

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60Co gamma-rays (Tateno et al., Int. J. Radiat. Res., 70:229-235, 1996) 3H β-rays (Kamiguchi et al. Mutation Res., 22:125-131, 1990)
Donor Dose No. of sperm Chromosome-type aberrations Chromatid-type aberrations Total* Donor Dose*** No. of sperm Chromosome-type aberrations Chromatid-type aberrations Total
(Gy) analyzed Breaks Exchanges Breaks Exchanges No. (per spermatozoon) (Gy) analyzed Breaks** Exchanges Breaks** Exchanges No. (per spermatozoon)
A 0 384 49 2 6 4 61 - 0 1,290 149 1 51 8 209
0.5 181 53 7 7 2 69 (0.195) 0.25 118 20 2 8 2 32 (0.109)
1 201 129 7 15 4 155 (0.612) 0.26 260 63 4 13 2 82 (0.153)
2 122 140 7 13 15 175 (1.276) 0.44 204 66 3 20 3 92 (0.289)
B 0 161 23 2 6 3 34 0.64 246 96 4 18 4 122 (0.334)
0.5 115 43 2 1 4 50 (0.224) 0.95 214 108 8 30 8 154 (0.558)
1 169 76 7 7 10 100 (0.381) 1.06 380 227 10 42 14 293 (0.609)
2 114 117 14 17 7 155 (1.149) 1.73 41 36 5 8 1 50 (1.058)
1.93 202 229 21 46 13 309 (1.368)
220 kVp X-rays (Kamiguchi et al., Mutation Res., 228:133-140, 1990) 3.74 177 291 33 78 29 431 (2.267)
Donor Dose No. of sperm Chromosome-type aberrations Chromatid-type aberrations Total
(Gy) analyzed Breaks** Exchanges Breaks** Exchanges No. (per spermatozoon) 252Cf neutrons (contaminated gamma=33 %) (Tateno et al. Int. J. Radiat. Res., 70:229-235, 1996)
0 2,097 277 16 34 53 380 Donor Dose No. of sperm Chromosome-type aberrations Chromatid-type aberrations Total
0.23 491 95 0 7 11 113 (0.049) (Gy) analyzed Breaks Exchanges Breaks Exchanges No. (per spermatozoon)
- 0.45 543 165 11 23 21 220 (0.224) A 0 165 32 2 2 2 38
0.91 819 455 19 46 35 555 (0.496) 0.5 110 56 7 3 4 71 (0.415)
1.82 1,009 921 50 107 79 1175 (0.983) 1 53 46 6 10 0 62 (0.940)
B 0 111 28 2 4 2 36
137Cs gamma-rays (Brandriff et al. Env. Mol. Mutagenesis, 12:167-177, 1988) 0.25 142 61 9 8 6 84 (0.267)
Donor Dose No. of sperm Chromosome-type aberrations Chromatid-type aberrations Total 0.5 88 54 4 10 5 73 (0.505)
(Gy) analyzed Breaks** Exchanges Breaks** Exchanges No. (per spermatozoon) C 0 184 33 2 0 1 36
0 121 4 0 1 1 6 0.25 259 94 8 12 4 118 (0.260)
1 97 16 3 0 0 19 (0.146) 1 152 119 15 19 28 181(0.995)
- 2 108 36 6 0 2 44 (0.358) *) Numbers in parentheses represent net induced frequencies
4 121 97 32 0 1 130 (1.025) **) Bereaks include "breaks", "fragments", "deletions" and "gaps". "Gaps" are less than 1 % of total breaks.
***) Sperm was irradiated in THO-containing BWW medium. Doses assume electron equibrium between medium and sperm.
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Chromosome aberrations in sperm of healthy and irradiated men (in vivo) 

[1] Spontaneous aberration frequencies in sperm of healthy men

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Authors No. of No. of sperm Chromosome abnormalities
donors analysed chrb ace del chrg chre mar+ chtb chtg chte Hyperhaploid Hypohaploid Multiple
Brandriff et al. 1984 4 909 37 11 0 0 1 0 6 0 8 5 9 0
Martin et al. 1987 30 1,582 35 30 4 11 12 5 3 12 11 20 53 2
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[2] Chromosome aberration frequencies in sperm of cancer patients after radiotherapy
             (Sperm may not necessarily be the prime target presenting chromosome aberrations in the sperm assay for in vivo irradiation because the sperm production is often preceeded by the depression of sperm count in patients received radiotherapy)

Chromosome aberration studies after radiotheray (RT);      Martin et al., Mutation Res., 174:219-225, 1986; Mutation Res., 226:21-30, 1989..
Patient ID Age Cancer Total radiation Testicular Abnormal complements/total complements at indicated time of sperm sampling* Average abnormality (%)
(year) dose (Gy) dose (Gy) Pre-RT 1 mo 3 mo 12 mo 24 mo 36 mo in post-RT
3 31 Seminoma 30 0.4 - - 0/1 0/6 6/47 1/16 10
5 20 Lymphoma 61.6 0.5 - - - - 0/2 2/13 13
11 28 Seminoma 30+25 0.6 0/1 - - - - -
1 29 Seminoma 30 0.8 - - - - - 2/10 20
7 24 Semonoma 30 0.8 - - - - 1/6 4/25 16
2 40 Seminoma 30 0.9 - - - - - 5/11 46
8 29 Seminoma 30 1.0 - - - - - 2/3 67
9 22 Seminoma 30 1.3 0/3 - - - - -
6 19 Teratoma 40 1.6 0/1 - - - - 1/4 25
12 20 Hodgkins 40 2.4 - - 1/1 - - - 100
4 47 Seminoma 30 3.1 0/4 - - - - -
10 39 Rectal cancer 45 5.0 - - - - - -
13 41 Muduloblastoma 41+33+36+20 ND - - - - - 1/4 25
*) Abnormalities include aneuploidy (n=36), chromosome-type and chromatid-type structural abnormalities (n=36) in 51 abnormal cellsfound in 337 cells analysed.
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