Vitamin D3 deficiency increases DNA damage and modify the expression of genes associated with hypertension in normotensive and hypertensive rats
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1
University of São Paulo, Brazil
Vitamin D3 is a lipophilic micronutrient obtained from the diet (salmon, sardines, mackerel and cod liver oil) or by the conversion of 7-dehydrocholesterol on skin after exposure to UVB radiation. This vitamin participates in several cellular processes, contributes to the maintenance of calcium concentrations, acts on phosphorus absorption, and is also related to the development and progression of chronic diseases. In hypertension, it is known that vitamin D3 act on renin-angiotensin-aldosterone system, regulates the gene expression and can induce or attenuate oxidative DNA damage. Vitamin D3 deficiency is present in 30-50% of human population (Pilz et al., 2009), and has been associated with increase of chromosomal instability and DNA damage (Nair-Shalliker; Armstrong; Fenech, 2012). Since experimental and clinical studies have suggested a relationship between vitamin D3 and blood pressure, the aim of this study was to evaluate whether vitamin D3 deficiency or supplementation lead to an increase or decrease in DNA damage, regulates the expression of genes associated with hypertension and changes the systolic blood pressure. Spontaneously hypertensive rats (SHR), used as a model of human essential hypertension, and their normotensive controls (Wistar Kyoto – WKY) were fed a control diet (vitamin D3 at 1.000 UI/kg), a deficient diet (vitamin D3 at 0 UI/kg) or a supplemented diet (vitamin D3 at 10.000 UI/kg) for 12 weeks. DNA damage was assessed by comet assay in cardiac muscle tissue and blood tissue, following the methodology proposed by Singh et al. (1988) and Tice et al. (2000); gene expression of 84 genes was assessed by RT2ProfilerTM PCR Array in cardiac muscle tissue; and systolic blood pressure was measured weekly by a noninvasive method using tail plethysmography. In SHR and WKY rats, vitamin D3 deficiency increased DNA damage in the blood tissue and did not change the DNA damage in cardiac muscle tissue; vitamin D3 supplementation maintained the DNA damage near the basal in both cardiac muscle and blood tissues. Regarding the expression profile of genes associated to hypertension, in both SHR and WKY rats, vitamin D3 deficiency increased the expression of gene Ace, involved in the pathway of the renin-angiotensin-aldosterone system. Five genes involved in the pathway of ion transport (Scnn1a and Scnn1g in SHR; Itpr1, Itpr2 and Itpr3 in WKY) and one gene associated with lipid metabolism (Sphk1 in SHR) also had their expression increased. Vitamin D3 supplementation decreased the expression of two genes (Ace and Agt in SHR) and increased the expression of one gene (Ace2 in WKY) involved in the pathway of the renin-angiotensin-aldosterone system. The expression of three genes involved in the pathway of ion transport (Scnn1a, Scnn1g and Scnn1b in SHR; Scnn1a and Scnn1g in WKY) and two genes involved in the pathway of smooth muscle contraction (Acta2 and Ednra in SHR; Ednra in WKY) were also decreased. Systolic blood pressure of SHR rats decreased after treatment with vitamin D3 supplementation, but vitamin D3 deficiency did not alter blood pressure in SHR and WKY rats. The results showed that vitamin D3 played an important role in molecular biology and blood pressure, and upon the genomic stability/instability. Down-regulation of genes involved in the renin-angiotensin-aldosterone system and ion transport was accompanied by a decrease in systolic blood pressure after vitamin D3 supplementation, suggesting a relationship between vitamin D3 supplementation and low blood pressure in hypertensive rats. In relation to the DNA damage, the results showed that the blood tissue was more sensitive to vitamin D3 deficiency in relation to cardiac tissue. It was also observed that vitamin D3 deficiency was genotoxic not only to SHR, but also to WKY rats, suggesting that there is an increase in DNA damage in hypertensive and normotensive individuals. In WKY rats, the increase of DNA damage in blood tissue, as well as the up-regulation of genes associated with hypertension, showed that vitamin D3 deficiency also had a negative effect in normotensive rats, suggesting that long periods of vitamin D3 deficiency could lead to development of hypertension.
Acknowledgements
FAPESP (process: 2012/04325-9), CAPES and CNPq.
References
Nair-Shalliker, V., Armstrong, B. K., and Fenech, M. (2012) Does vitamin D protect against DNA damage? Mutation Research 733, 50-57. doi: 10.1016/j.mrfmmm.2012.02.005
Pilz, S., Tomaschitz, A., Ritz, E., and Pieber, T.R. (2009) Vitamin D status and arterial hypertension: a systematic review. Nature Reviews Cardiology 6, 621-630. doi: 10.1038/nrcardio.2009
Singh, N. P., McCoy, M.T., Tice, R.R., and Schneider, E.L. (1988) A simple technique for quantitation of low levels of DNA damage in individual cells. Experimental Cell Research 175, 184-191
Tice, R. R., Agurell, E., Anderson, D., Burlinson, B., Hartmann, A., Kobayashi, H., Miyamae, Y., Rojas, E., Ryu, J.C., and Sasaki, Y.F. (2000) Single cell gel/comet assay: guidelines for in vitro and in vivo genetic toxicology testing. Environmental Molecular Mutagenesis 35, 206-221
Keywords:
Vitamin D3,
Nutrigenomics,
gene-diet interaction,
DNA Damage,
Comet Assay
Conference:
ICAW 2015 - 11th International Comet Assay Workshop, Antwerpen, Belgium, 1 Sep - 4 Sep, 2015.
Presentation Type:
Poster Presentation
Topic:
The effect of nutrition on DNA damage and DNA repair
Citation:
Machado
CS,
Aissa
AF,
Hernandes
LC,
Mello
MB,
Bianchi
MP and
Antunes
LG
(2015). Vitamin D3 deficiency increases DNA damage and modify the expression of genes associated with hypertension in normotensive and hypertensive rats.
Front. Genet.
Conference Abstract:
ICAW 2015 - 11th International Comet Assay Workshop.
doi: 10.3389/conf.fgene.2015.01.00060
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Received:
04 May 2015;
Published Online:
23 Jun 2015.
*
Correspondence:
Dr. Carla S Machado, University of São Paulo, Ribeirão Preto, São Paulo, Brazil, krla_machado@yahoo.com.br