The Concurrence of Hypercholesterolemia and Aging Promotes DNA Damage in Apolipoprotein E-Deficient Mice

Sara P Dalboni, Bianca P Campagnaro, Clarissa L Tonini, Elisardo C Vasquez, Silvana S Meyrelles

Biotechnology Graduate Program, Health Sciences Center, Federal University of Espirito Santo, Vitoria, ES, Brazil.
Biotechnology Graduate Program, Health Sciences Center, Federal University of Espirito Santo, Vitoria, ES, Brazil;Dept. Physiological Sciences, Health Sciences Center, Federal University of Espirito Santo, Vitoria, ES, Brazil.
Dept. Physiological Sciences, Health Sciences Center, Federal University of Espirito Santo, Vitoria, ES, Brazil.
Emescam College of Health Sciences, ES, Brazil.

DOI: 10.4236/ojbd.2012.23010                

Abstract

Recent evidence shows that increased oxidative stress and aging contribute to DNA damage in various cardiovascular diseases such as lipid disorders and atherosclerosis. In the present study, we used the comet assay to evaluate the influ- ence of aging on DNA damage in whole blood cells from apolipoprotein E-deficient (apoE?/?) mice and compared the results to those found in cells from wild-type C57BL/6 (C57) mice. Using the alkaline comet assay and fluorescent ethidium bromide staining, DNA damage was analyzed in the peripheral whole blood (5 μL) cells that were isolated from either young (8-week-old) and elderly (72-week-old) apoE?/? mice or from age-matched C57 mice. The levels of total plasma cholesterol were approximately 6-fold higher in apoE?/? mice of both ages compared to C57 mice. Elderly apoE?/? mice showed significantly higher levels of DNA damage (19%) compared to elderly C57 mice (8%, p < 0.01) and young apoE?/? mice (10%, p < 0.01). The comet assay in whole blood cells is a suitable technique for the detection of DNA damage in the apoE?/? mouse; it is an easy, rapid, inexpensive and sensitive method. The novelty of this study is that DNA damage occurring in whole blood cells of this murine model requires the concurrence of aging and oxida- tive stress-related hypercholesterolemia.

Keywords

DNA Damage; Oxidative Stress; apoE Knockout Mice; Aging; Blood Cells

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	R. Ross, “Atherosclerosis—An Inflammatory Disease,” New England Journal of Medicine, Vol. 340, No. 2, 1999, pp. 115-126. doi:10.1056/NEJM199901143400207
[2]	E. C. Vasquez, V. A. Peotta, A. L. Gava, T. M. Pereira and S. S. Meyrelles, “Cardiac and Vascular Phenotypes in the Apolipoprotein E-Deficient Mouse,” Journal of Biomedical Sciences, Vol. 19, No. 1, 2012, p. 22. doi:10.1186/1423-0127-19-22
[3]	T. M. C. Pereira, B. V. Nogueira, L. C. F. Lima, M. L. Porto, J. A. Arruda, E. C. Vasquez and S. S. Meyrelles, “Cardiac and Vascular Changes in Elderly Atherosclerotic Mice: The Influence of Gender,” Lipids in Health and Disease, Vol. 9, No. 1, 2010, p. 87. doi:10.1186/1476-511X-9-87
[4]	M. L. Porto, L. C. Lima, T. M. Pereira, B. V. Nogueira, C. L. Tonini, B. P. Campagnaro, S. S. Meyrelles and E. C. Vasquez, “Mononuclear Cell Therapy Attenuates Atherosclerosis in ApoE KO Mice,” Lipids in Health and Disease, Vol. 10, No. 1, 2011, p. 155. doi:10.1186/1476-511X-10-155
[5]	P. Hasty, J. Campisi, J. Hoeijmakers, H. van Steeg and J. Vijg, “Aging and Genome Maintenance: Lessons from the Mouse?” Science, Vol. 299, No. 5611, 2003, pp. 13551359. doi:10.1126/science.1079161
[6]	S. S. Meyrelles, V. A. Peotta, T. M. Pereira and E. C. Vasquez, “Endothelial Dysfunction in the Apolipoprotein E-Deficient Mouse: Insights into the Influence of Diet, Gender and Aging,” Lipids in Health and Disease, Vol. 10, 2011, p. 211. doi:10.1186/1476-511X-10-211
[7]	D. P. Lovell and T. Omori, “Statistical Issues in the Use of the Comet Assay,” Mutagenesis, Vol. 23, No. 3, 2008, pp. 171-182. doi:10.1093/mutage/gen015
[8]	M. Z. Vasquez, “Recommendations for Safety Testing with the in Vivo Comet Assay,” Mutation Research/Genetic Toxicology and Environmental Mutagenesis, Vol. 747, No. 1, 2012, pp. 142-156. doi:10.1016/j.mrgentox.2012.05.002
[9]	J. K. Folkmann, S. Loft and P. M?ller, “Oxidatively Damaged DNA in Aging Dyslipidemic ApoE?/? and Wild-Type Mice,” Mutagenesis, Vol. 22, No. 2, 2007, pp. 105-110. doi:10.1093/mutage/gel059
[10]	N. P. Singh, M. T. McCoy, R. R. Tice and E. L. Schneider, “A Simple Technique for Quantitation of Low Levels of DNA Damage in Individual Cells,” Experimental Cell Research, Vol. 175, No. 1, 1988, pp. 184-191. doi:10.1016/0014-4827(88)90265-0
[11]	M. F. Ellahue?e, L. P. Pérez-Alzola, M. Farfán-Urzua, P. González-Hormazabal, M. Garay, M. I. Olmedo and J. A. Last, “Preliminary Evaluation of DNA Damage Related with the Smoking Habit Measured by the Comet Assay in Whole Blood Cells,” Cancer Epidemiology Biomarkers & Prevention, Vol. 13, No. 7, 2004, pp. 1223-1229. http://cebp.aacrjournals.org/content/13/7/1223
[12]	C.-H. Chuang and M.-L. Hu, “Use of Whole Blood Directly for Single-Cell Gel Electrophoresis (Comet) Assay in Vivo and White Blood Cells for in Vitro Assay,” Mutation Research, Vol. 564, No. 1, 2004, pp. 75-82. doi:10.1016/j.mrgentox.2004.07.013
[13]	T. A. Alvarenga, M. L. Andersen, D. A. Ribeiro, P. Araujo, C. Hirotsu, J. L. Costa, M. C. Battist and S. Tufik, “Single Exposure to Cocaine or Ecstasy Induces DNA Damage in Brain and Other Organs of Mice,” Addiction Biology, Vol. 15, No. 1, 2010, pp. 96-99. doi:10.1111/j.1369-1600.2009.00179.x
[14]	L. J. Marnett, “Oxyradicals and DNA Damage,” Carcinogenesis, Vol. 21, No. 3, 2000, pp. 361-370. doi:10.1093/carcin/21.3.361
[15]	R. F. Lee and S. Steinert, “Use of the Single Cell Gel Electrophoresis/Comet Assay for Detecting DNA Damage in Aquatic (Marine and Freshwater) Animals,” Mutation Research/Reviews in Mutation Research, Vol. 544, No. 1, 2003, pp. 43-64. doi:10.1016/S1383-5742(03)00017-6
[16]	A. R. Collins, “The Comet Assay for DNA Damage and Repair: Principles, Applications, and Limitations,” Molecular Biotechnology, Vol. 26, No. 3, 2004, pp. 249-261. doi:10.1385/MB:26:3:249
[17]	Z. M. Guo, H. Yang, M. L. Hamilton, H. VanRemmen and A. Richardson, “Effects of Age and Food Restriction on Oxidative DNA Damage and Antioxidant Enzyme Activities in the Mouse Aorta,” Mechanisms of Ageing and Development, Vol. 122, No. 15, 2001, pp. 1771-1786. doi:10.1016/S0047-6374(01)00298-6
[18]	H. F. Zou, E. Stoppani, D. Volonte and F. Galbiati, “Caveolin-1, Cellular Senescence and Age-Related Diseases,” Mechanisms of Ageing and Development, Vol. 132, No. 11-12, 2001, pp. 533-542. doi:10.1016/j.mad.2011.11.001
[19]	Q. M. Chen, “Replicative Senescence and Oxidant-Induced Premature Senescence. Beyond the Control of Cell Cycle Checkpoints,” Annals of the New York Academy of Sciences, Vol. 908, No. 6, 2000, pp. 111-125. doi:10.1111/j.1749-6632.2000.tb06640.x