The Usefulness of Viscometric Analysis for Detecting Minimal Levels of DNA Fragmentation

Abstract

Basic requirements for a method used to study the genotoxic potential of xenobiotic agents in the intact animal are sensitivity and capability of detecting the effect of the compound under test in various tissues. A new viscometric technique, which has been found capable of measuring DNA damage in liver, kidney, and lung of rats treated with small single doses of 10 chemical carcinogens, seems to possess such requirements. Single-strand breaks and probably other types of lesions indeed cause changes in DNA supercoiling which can be sensitively measured by monitoring time-dependent changes of DNA viscosity. The main advantage of this technique is that clear-cut modifications of viscometric parameters can be obtained with doses of various carcinogens markedly lower than those found to be the minimal effective ones in other commonly employed short-term in vivo tests. The importance of studying the genotoxic effects of pharmacologically meaningful doses is discussed.

References

1. Ashby J (1983). The unique role of rodents in the detection of possible human carcinogens and mutagens. Mutat. Res 115: 177–213.

2. Damjanov I , Cox R , Sarma DSR , and Farber E (1973). Patterns of damage and repair of liver DNA induced by carcinogenic methylating agents in vivo. Cancer Res. 33: 2122–2128.

3. Petzold GL and Swenberg JA (1978). Detection of DNA damage induced in vivo following exposure of rats to carcinogens. Cancer Res. 38: 1589–1594.

4. Parodi S , Taningher M , Santi L , Cavanna M , Sciabà L , Maura A , and Brambilla G (1978). A practical procedure for testing DNA damage in vivo proposed for a prescreening of chemical carcinogens. Mutat. Res. 54: 39–46.

5. Nicolini C , Cavanna M , Maura A . Pino A , Robbiano L , Biassoni F , Ricci R , Belmont A , Ziels S , and Brambilla G (1982). DNA alkaline elution: physical basis of the elution process and validation of this method as a screening procedure to identify chemical carcinogens. In: Chemical Carcinogenesis, C Nicolini (ed). Plenum Press, New York, pp. 93–119.

6. Parodi S , Carlo P , Martelli A , Tannigher M , Finollo R . Pala M , and Giaretti W (1981). A circular channel crucible oscillating viscometer: detection of DNA damage induced in vivo by exceedingly small doses of dimethylnitrosamine. J. Mol. Biol. 147: 501–521.

7. Nicolini C , Carlo P , Martelli A , Finollo R , Bignone FA , Patrone E , Trefiletti V , and Brambilla G (1982). Viscoelastic properties of native DNA from intact nuclei of mammalian cells. High-order DNA packing and cell function. J. Mol. Biol. 161: 155–175.

8. Brambilla G , Carlo P , Finollo R , Bignone FA , Ledda A , and Cajelli E (1983). Viscometric detection of liver DNA fragmentation in rats treated with minimal doses of chemical carcinogens. Cancer Res. 43: 202–209.

9. Carlo P , Finollo R , Ledda A , Bignone FA , and Brambilla G (1983). Viscometric analysis of DNA damage in kidney and lung following exposure of rats to small doses of chemical carcinogens. Carcinogenesis 4: 137–140.

10.

10. Wiersma DA and Roth RA (1983). Clearance of benzo(a)pyrene by isolated rat liver and lung: alterations in perfusion and metabolic capacity. J. Pharmacol. Exp. Ther. 225: 121–125.

11.

11. Frantz CN and Mailing HV (1975). Factors affecting metabolism and mutagenicity of dimethylnitrosamine and diethylnitrosamine. Cancer Res. 35: 2306–2314.

12.

12. Lutz WK , Viviani AN , and Schlatter C (1978). Nonlinear dose-response relationships for the binding of the carcinogen benzo(a)pyrene to rat liver DNA in vivo. Cancer Res. 38: 575–578.

13.

13. Williams JR , Little JB , and Shipley WU (1974). Association of mammalian cell death with a specific endonucleolytic degradation of DNA. Nature 252: 754–755.

14.

14. Pegg AE and Hui G (1978). Removal of methylated purines from rat liver DNA after administration of dimethylnitrosamine. Cancer Res. 38: 2011–2107.

15.

15. Stumpf R , Margison GP , Montesano R , and Pegg AE (1979). Formation and loss of alkylated purines from DNA of hamster liver after administration of dimethylnitrosamine. Cancer Res. 39: 50–54.

16.

16. Adler ID (1980). A review of the coordinated research effort on the comparison of test systems for the detection of mutagenic effects sponsored by the E.E.C. Mutat. Res. 74: 77–93.

17.

17. Simmon VF , Rosenkranz HS , Zeiger E , and Poirier LA (1979). Mutagenic activity of chemical carcinogens and related compounds in the intraperitoneal host-mediated assay. J. Natl. Cancer Inst. 62: 911–918.

18.

18. Trzos RJ , Petzold GL , Brunden MN , and Swenberg JA (1978). The evaluation of sixteen carcinogens in the rat using the micronucleus test. Mutat. Res. 58: 79–86.

19.

19. Latt SA , Allen J , Bloom SE , Carrano A . Falke E , Kram D , Schneider E , Schreck R , Tice R , Whitfield B , and Wolff S (1981). Sister chromatid exchanges: a report of the gene-tox program. Mutat. Res. 87: 17–62.