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. 1997 Jul;2(2):53–58. doi: 10.1007/BF02931964

Single-cell gel electrophoresis (SCG)-A review and discussion

Yuquan Lu 1,✉, Tatsuya Takeshita 1,✉, Kanehisa Morimoto 1,✉
PMCID: PMC2723433  PMID: 21432452

Abstract

Single-cell gel electrophoresis (SCG) is a simple, sensitive and effective technique. Being able to reflect quantitatively the genotoxicity of many hazardous agents, it is promising for application in environmental genotoxic monitoring and the study of carcinogenesis. In clinics, it can be used to evaluate the DNA repair ability and monitor DNA breaks during cancer therapy. As a biomarker, it has its own merits and limitations, being different from other biomarkers such as sister chromatid exchange (SCE) test and micronuclei (MN) assay. In many studies, it is more sensitive than SCE or MN. Combination studies with other biomarkers like SCE, MN, chromosomal aberration, bcl-2 and genetic polymorphisms have begun to demonstrate its great importance for the understanding of carcinogenesis and the genotoxicities of environmental factors.

Key words: Single-cell gel electrophoresis, Comet assay, Biomarker, DNA strand breaks, Genotoxicity

References

  • 1).Singh NP, McCoy MT, Tice RR, Schneider EL. A simple technique for quantitation of low levels of DNA damage in individual cells. Exp Cell Res 1988;175: 184–91. [DOI] [PubMed]
  • 2).Duthie SJ, Ma A, Ross MA, Collins AR. Antioxidant supplementation decreases oxidative DNA damage in human lymphocytes. Cancer Res 1996;56: 1291–5. [PubMed]
  • 3).Pandrangi R, Petras M, Ralph S, Vrzoc M. Alkaline single cell gel (comet) assay and genotoxicity monitoring using bullheads and carp. Environ Mol Mutagen 1995;26: 234–56. [DOI] [PubMed]
  • 4).Plappert U, Raddatz K, Roth S, Fliedner TM. DNA-damage detection in man after radiation exposure—the comet assay—its possible application for human biomonitoring. Stem Cells (Dayt) 1995;13 Suppl 1:215–22. [PubMed]
  • 5).Tice RR, Strauss GH. The single cell gel electrophoresis/comet assay: A potential tool for detecting rediation-induced DNA damage in humans. Stem Cells (Dayt) 1995;13 Suppl 1: 207–14. [PubMed]
  • 6).Olive PL, Vikse CM, Durand RE. Hypoxic fractions measured in murine tumors and normal tissues using the comet assay. Int J Radiat Oncol Biol Phys 1994;29: 487–91. [DOI] [PubMed]
  • 7).Olive PL, Durand RE, Le Riche J, Olivotto IA, Jackson SM. Gel electrophoresis of individual cells to quantify hypoxic fraction in human breast cancers. Cancer Res 1993;53: 733–6. [PubMed]
  • 8).Tice RR, Strauss GH, Peters WP. High-dose combination alkylating agents with autologous bone-marrow support in patients with breast cancer: preliminary assessment of DNA damage in individual peripheral blood lymphocytes using the single cell gel electrophoresis assay. Mutat Res 1992;271: 101–13. [DOI] [PubMed]
  • 9).Delaney CA, Green MH, Lowe JE, Green IC. Endogenous nitric oxide induced by interleukin-1 beta in rat islets of Langerhans and HIT-T15 cells causes significant DNA damage as measured by the ‘comet’ assay. FEBS Lett 1993;333: 291–5. [DOI] [PubMed]
  • 10).Gedik CM, Ewen SW, Collins AR. Single-cell gel electrophoresis applied to the analysis of UV-C damage and its repair in human cells. Int J Radiat Biol 1992;62: 313–20. [DOI] [PubMed]
  • 11).Sardas S, Walker D, Akyol D, Karakaya AE. Assessment of smoking- induced DNA damage in lymphocytes of smoking mothers of newborn infants using the alkaline single-cell gel electrophoresis technique. Mutat Res 1995;335: 213–7. [DOI] [PubMed]
  • 12).Betti C, Davini T, Giannessi L, Loprieno N, Barale R. Microgel electrophoresis assay (comet test) and SCE analysis in human lymphocytes from 100 mornal subjects. Mutat Res 1994;307: 323–33. [DOI] [PubMed]
  • 13).Betti C, Davini T, Giannessi L, Loprieno N, Barale R. Comparative studies by comet test and SCE analysis in human lymphocytes from 200 healthy subjects. Mutat Res 1995;343: 201–7. [DOI] [PubMed]
  • 14).Hartmann A, Plappert U, Raddatz K, Grunert Fuchs M, Speit G. Does physical activity induce DNA damage? Mutagenesis 1994;9: 269–72. [DOI] [PubMed]
  • 15).Meyers CD, Fairbairn DW, O‘Neill KL. Measuring the repair of H2O2-induced DNA single strand breaks using the single cell gel assay. Cytobios 1993;74: 147–53. [PubMed]
  • 16).Fairbairn DW, Reyes WA, Van Grigsby R, O‘Neill KL. Laser scanning microscopic analysis of DNA damage in frozen tissues. Cancer Lett 1994;76: 127–32. [DOI] [PubMed]
  • 17).Collins AR, Ma AG, Duthie SJ. The kinetics of repair of oxidative DNA damage (strand breaks and oxidised pyrimidines) in human cells. Mutat Res 1995;336: 69–77. [DOI] [PubMed]
  • 18).Holz O, Jorres R, Kastner A, Krause T, Magnussen H. Reproducibility of basal and induced DNA single-strand breaks detected by the single- cell gel electrophoresis assay in human peripheral mononuclear leukocytes. Int Arch Occup Environ Health 1995;67: 305–10. [DOI] [PubMed]
  • 19).Holz O, Jorres R, Kastner A, Magnussen H. Differences in basal and induced DNA single-strand breaks between human peripheral monocytes and lymphocytes. Mutat Res 1995;332: 55–62. [DOI] [PubMed]
  • 20).Barber CV, Fantel AG. The role of oxygenation in embryotoxic mechanisms of three bioreducible agents. Teratology 1993;47: 209–23. [DOI] [PubMed]
  • 21).Pfuhler S, Wolf HU. Detection of DNA-crosslinking agents with the alkaline comet assay. Environ Mol Mutagen 1996;27: 196–201. [DOI] [PubMed]
  • 22).Anderson D, Yu TW, Schmezer P. An investigation of the DNA-damaging ability of benzene and its metabolites in human lymphocytes, using the comet assay. Environ Mol Mutagen 1995;26: 305–14. [DOI] [PubMed]
  • 23).Muller WU, Bauch T, Streffer C, Niedereichholz F, Bocker W. Comet assay studies of radiation-induced DNA damage and repair in various tumour cell lines. Int J Radiat Biol 1994;65: 315–9. [DOI] [PubMed]
  • 24).Plewa MJ, Wagner ED, Yu TW, Anderson D. Genotoxicity of mphenylenediamine and 2-aminofluorene in Salmonella typhimurium and human lymphocytes with and without plant activation. Environ Mol Mutagen 1995;26: 171–7. [DOI] [PubMed]
  • 25).Taj S, Nagarajan B. Induction of genotoxicity by salted deep-fried fish and mutton. Mutat Res 1994;322: 45–54. [DOI] [PubMed]
  • 26).Green MH, Lowe JE, Waugh AP, Aldridge KE, Cole J, Arlett CF. Effect of diet and vitamin C on DNA strand breakage in freshly-isolated human white blood cells. Mutat Res 1994;316: 91–102. [DOI] [PubMed]
  • 27).Hartmann A, Niess AM, Grunert Fuchs M, Poch B, Speit G. Vitamin E prevents exercise-induced DNA damage. Mutat Res 1995;346: 195–202. [DOI] [PubMed]
  • 28).Anderson D, Yu TW, Phillips BJ, Schmezer P. The effect of various antioxidants and other modifying agents on oxygen-radical-generated DNA damage in human lymphocytes in the COMET assay. Mutat Res 1994;307: 261–71. [DOI] [PubMed]
  • 29).Plappert U, Barthel E, Seidal HJ. Reduction of benzene toxicity by toluene. Environ Mol Mutagen 1994;24: 283–92. [DOI] [PubMed]
  • 30).Verschaeve L, Gilles J. Single cell gel electrophoresis assay in the earthworm for the earthworm for the detection of genotoxic compounds in soils. Bull Environ Contam Toxicol 1995;54: 112–9. [DOI] [PubMed]
  • 31).Koppen GL. Verschaeve. The alkaline comet test on plant cells: A new genotoxicity test for DNA strand breaks in Vicia faba root cells. Mutat Res 1996;360: 193–200. [DOI] [PubMed]
  • 32).Fairbairn D, Meyers D, O’Neill K. Detection of DNA damaging agents in environmental water samples. Bull Environ Contam Toxicol 1994;52: 687–90. [DOI] [PubMed]
  • 33).Pool Zobel BL, Guigas C, Klein R, Neudecker C, Renner HW, Schmezer P. Assessment of genotoxic effects by lindane. Food Chem Toxicol 1993;31: 271–83. [DOI] [PubMed]
  • 34).Ribas G, Frenzilli G, Barale R, Marcos R. Herbicide-induced DNA damage in human lymphocytes evaluated by the single-cell gel electrophoresis (SCGE) assay. Mutat Res 1995;344: 41–54. [DOI] [PubMed]
  • 35).Hejmadi MV, McKeown SR, Friery OP, McIntyre IA, Patterson LH, Hirst DG. DNA damage following combination of radiation with the bioreductive drug AQ4N: Possible selective toxicity to oxic and hypoxic tumour cells. Br J Cancer 1996;73: 499–505. [DOI] [PMC free article] [PubMed]
  • 36).de With A, Leitz G, Greulich KO. UV-Bk-laser-induced DNA damage in lymphocytes observed by single-cell gel electrophoresis. J Photochem Photobiol B 1994;24: 47–53. [DOI] [PubMed]
  • 37).Vijayalaxmi, Strauss GH, Tice RR. An analysis of gamma-ray-induced DNA damage in human blood leukocytes, lymphocytes and granulocytes. Mutat Res 1993;292: 123–8. [DOI] [PubMed]
  • 38).Vijayalaxmi, Tice RR, Strauss GH. Assessment of radiation-induced DNA damage in human blood lymphocytes using the single-cell gel electrophoresis technique. Mutat Res 1992;271: 243–52. [DOI] [PubMed]
  • 39).Jostes RF, Hui TE, Cross FT. Single-cell gel technique supports hit probability calculations. Health Phys 1993;64: 675–9. [DOI] [PubMed]
  • 40).de With A, Greulich KO. Wavelength dependence of laser-induced DNA damage in lymphocytes observed by single-cell gel electrophoresis. J Photochem Photobiol B 1995;30: 71–6. [DOI] [PubMed]
  • 41).Hara A, Zhang W, Kobayashi H, Niikawa S, Sakai N, Yamada H. A single cell gel electrophoresis technique for the detection of DNA damage induced by ACNU, an alkylating agent or irradiation in murine glioma cell lines. Neurol Res 1994;16: 234–40. [DOI] [PubMed]
  • 42).Olive PL, Banath JP. Radiation-induced DNA double-strand breaks produced in histone-depleted tumor cell nuclei measured using the neutral comet assay. Radiat Res 1995;142: 144–52. [DOI] [PubMed]
  • 43).Arlett CF, Lowe JE, Harcourt SA, Waugh AP, Cole J, Roza L, Diffey BL, Mori T, Nikaido O, Green MH. Hypersensitivity of human lymphocytes to UV-B and solar irradiation. Cancer Res 1993;53: 609–14. [PubMed]
  • 44).Miller DL, Thomas RM, Buschbom RL. Comet assay reveals DNA strand breaks induced by ultrasonic cavitation in vitro. Ultrasound Med Biol 1995;21: 841–8. [DOI] [PubMed]
  • 45).Kligerman AD, Mottus K, Erexson GL. Cytogenetic analyses of the in vitro and in vivo responses of murine cells to peroxyacetyl nitrate (PAN). Mutat Res 1995;341: 199–206. [DOI] [PubMed]
  • 46).Ashby J, Tinwell H, Lefevre PA, Browne MA. The single cell gel electrophoresis assay for induced DNA damage (comet assay): Measurement of tail length and moment. Mutagenesis 1995;10: 85–90. [DOI] [PubMed]
  • 47).Plappert U, Barthel E, Raddatz K, Seidel HJ. Early effects of benzene exposure in mice. Hematological versus versus genotoxic effects. Arch Toxicol 1994;68: 284–90. [DOI] [PubMed]
  • 48).Vaghef H, Hellman B. Demonstration of chlorobenzene-induced DNA damage in mouse lymphocytes using the single cell gel electrophoresis assay. Toxicology 1995;96: 19–28. [DOI] [PubMed]
  • 49).Vodicka P, Bastlova T, Vodickova L, Peterkova K, Lambert B, Hemminki K. Biomarkers of styrene exposure in lamination workers: Levels of O6-guanine DNA adducts, DNA strand breaks and mutant frequencies in the hypoxanthine quanine phosphoribosyltransferase gene in T-lymphocytes. Carcinogenesis 1995;16: 1473–81. [DOI] [PubMed]
  • 50).Bastlova T, Vodicka P, Peterkova K, Hemminki K, Lambert B. Styrene oxide-induced HPRT mutations, DNA adducts and DNA strand breaks in cultured human lymphocytes. Carcinogenesis 1995;16: 2357–62. [DOI] [PubMed]
  • 51).De Meo M, Laget M, Castegnaro M, Dumenil G. Genotoxic activity of potassium permanganate in acidic solutions. Mutat Res 1991;260: 295–306. [DOI] [PubMed]
  • 52).Singh NP, Tice RR, Stephens RE, Schneider EL. A microgel electrophores is technique for the direct quantitation of DNA damage and repair in individual fibroblasts cultured on microscope slides. Mutat Res 1991;252: 289–96. [DOI] [PubMed]
  • 53).Rojas E, Valverde M, Herrera LA, Altamirano Lozano M, Ostrosky Wegman P. Genotoxicity of vanadium pentoxide evaluate by the single cell gel electrophoresis assay in human lymphocytes. Mutat Res 1996;359: 77–84. [DOI] [PubMed]
  • 54).Bjorge C, Wiger R, Holme JA, Brunborg G, Andersen R, Dybing E, Soderlund EJ. In vitro toxicity of 1, 2-dibromo-3-chloropropane (DBCP) in different testicular cell types from rats. Reprod Toxicol 1995;9: 461–73. [DOI] [PubMed]
  • 55).Churg A, Keeling B, Gilks B, Porter S, Olive P. Rat mesothelial and tracheal epithelial cells show equal DNA sensitivity to hydrogen peroxide- induced oxidant injury. Am J Physiol 1995;268 (5 Pt 1): 1832–8. [DOI] [PubMed]
  • 56).Ward AJ, Olive PL, Burr AH, Rosin MP. Response of fibroblast cultures from ataxia-telangiectasia patients to reactive oxygen species generated during inflammatory reactions. Environ Mol Mutagen 1994;24: 103–11. [DOI] [PubMed]
  • 57).Nocentini S. Comet assay analysis of repair of DNA strand breaks in normal and deficient human cells exposed to radiations and chemicals. Evidence for a repair pathway specificity of DNA ligation. Radiat Res 1995;144: 170–80. [DOI] [PubMed]
  • 58).Olive PL, Durand RE. Detection of hypoxic cells in a murine tumor with the use of the comet assay. J Natl Cancer Inst 1992;84: 707–11. [DOI] [PubMed]
  • 59).Hu Q, Kavanagh MC, Newcombe D, Hill RP. Detection of hypoxic fractions in murine tumors by comet assay: Comparison with other techniques. Radiat Res 1995;144: 266–75. [DOI] [PubMed]
  • 60).Olive PL. Use of the comet assay to detect hypoxic cells in murine tumours and normal tissues exposed to bioreductive drugs. Acta Oncol 1995;34: 301–5. [DOI] [PubMed]
  • 61).Peitsch MC, Muller C, Tschopp J. DNA fragmentation during apoptosis is caused by frequent single-strand cuts. Nucleic Acids Res 1993;21:4206–929. [DOI] [PMC free article] [PubMed]
  • 62).Fairbairn DW, Carnahan KG, Thwaits RN, Grigsby RV, Holyoak GR, O’Neill KL. Detection of apoptosis induced DNA cleavage in scrapie- infected sheep brain. FEMS Microbiol Lett 1994;115: 341–6. [DOI] [PubMed]
  • 63).Olive PL, Frazer G, Banath JP. Radiation-induced apoptosis measured in TK6 human B lymphoblast cells using the comet assay. Radiat Res 1993;136: 130–6. [DOI] [PubMed]
  • 64).Gopalakrishna P, Khar A. Comet assay to measure DNA damage in apoptotic cells. J Biochem Biophys Methods 1995;30: 69–73. [DOI] [PubMed]
  • 65).Musk SR, Astley SB, Edwards SM, Stephenson P, Hubert RB, Johnson IT. Cytotoxic and clastogenic effects of benzyl isothiocyanate towards cultured mammalian cells. Food Chem Toxicol 1995;33: 31–7. [DOI] [PubMed]
  • 66).Hartmann A, Speit G. Comparative investigations of the genotoxic effects of metals in the single cells gel (SCG) assay and the sister chromatid exchange (SCE) test. Environ Mol Mutagen 1994;23: 299–305. [DOI] [PubMed]
  • 67).Kim JP, D’Arpa P, Jacobson Kram D, Williams JR. Ultraviolet-light exposure induces a heritable sensitivity to the induction of SCE by mitomycin-C. Mutat Res 1985;149: 437–42. [DOI] [PubMed]
  • 68).Kligerman AD, Allen JW, Erexson GL, Morgan DL. Cytogenetic studies of rodents exposed to styrene by inhalation. IARC Sci Publ 1993; (127): 217–24. [PubMed]
  • 69).Ward AJ, Olive PL, Burr AH, Rosin MP. A sensitivity to oxidative stress is linked to chromosome 11 but is not due to a difference in single strand DNA breakage or repair. Mutat Res 1993;294: 299–308. [DOI] [PubMed]
  • 70).Malcolmson AM, Davies G, Hanson JA, Deeley JO, Gaffney CC, McGregor AD, Kerby IJ. Determination of radiation-induced damage in lymphocytes using the micronucleus and microgel electrophoresis ‘Comet’ assays. Eur J Cancer 1995;31A: 2320–3. [DOI] [PubMed]
  • 71).Tuo J, Loft S, Thomsen MS, Poulsen HE. Benzene-induced genotoxicity in mice in vivo detected by the alkaline comet assay: Reduction by CYP2E1 inhibition. Mutat Res 1996;368: 213–9. [DOI] [PubMed]
  • 72).Fairbairn D, O’Neill KL, Standing MD. Application of confocal laser scanning microscopy to analysis of H2O2-induced DNA damage in human cells. Scanning 1993;15: 136–9. [DOI] [PubMed]
  • 73).O’Neill KL, Fairbairn DW, Standing MD. Analysis of single-cell gel electrophoresis using laser-scanning microscopy. Mutat Res 1993;319: 129–34. [DOI] [PubMed]
  • 74).Kreja L, Selig C, Nothdurft W. Assessment of DNA damage in canine peripheral blood and bone marrow after total body irradiation using the single-cell gel electrophoresis technique. Mutat Res 1996;359: 63–70. [DOI] [PubMed]
  • 75).Kamesaki S, Kamesaki H, Jorgensen TJ, Tanizawa A, Pommier Y, Cossman J. bcl-2 protein inhibits etoposide-induced apoptosis through its effects on events subsequent to topoisomerase II-induced DNA strand breaks and their repair [published erratum appears in Cancer Res 1994;54: 3074]. Cancer Res 1993; 53: 4251-6. [PubMed]

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