title: Accumulation of 8-oxo-deoxyguanosine in cardiovascular tissues with the development of hypertension.
abstract: Accumulation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG) in DNA is associated with mutagenesis and cell death. Little attention has been given to the biological significance of 8-oxo-dG accumulation in cardiovascular tissues during the different stage of hypertension and its prevention. We thus investigated the levels and localization of both 8-oxo-dG accumulation and expression of MTH1, which hydrolyzes 8-oxo-dGTP to prevent its incorporation into DNA, in the thoracic aorta prepared from stroke-prone spontaneously hypertensive rats (SHRSP) and age-matched Wister-Kyoto rats (WKY), aged 5-32 weeks. HPLC-MS/MS analysis revealed that the levels of nuclear 8-oxo-dG in the aorta increased significantly in SHRSP, but not WKY, with aging. Immunohistochemical study revealed that both TUNEL reactivity and 8-oxo-dG immunoreactivity were increased in smooth muscle cells (SMC) and endothelial cells (EC) of the aorta with aging, and they exhibited similar distributions in serial sections. The number of 8-oxo-dG and TUNEL positive cells in EC, but not in SMC, was significantly higher in SHRSP than WKY at 32 weeks of age. In contrast, the expression levels of Mth1mRNA and MTH1 protein in the aorta were similarly decreased both in SHRSP and WKY with aging. However, the number of MTH1 expressing EC was remarkably increased in the older SHRSP compared to the younger ones or age-matched WKY. Hypertension significantly increased not only 8-oxo-dG accumulation but also the expression of MTH1 in EC of the aorta during aging. While accumulation of 8-oxo-dG in SMC of the aorta was slightly increased, the expression of MTH1 protein in SMC was rather decreased by hypertension. We thus suggest that MTH1 may protect EC in the aorta from the oxidative damage increased by hypertension.
authors.affiliation: Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Ohtsubo
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Ohya
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Kansui
authors.forename: Masato
authors.initials: M
authors.lastname: Furuichi
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Matsumura
authors.forename: Koji
authors.initials: K
authors.lastname: Fujii
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Iida
authors.forename: Yusaku
authors.initials: Y
authors.lastname: Nakabeppu
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000818:Animals; D017209:Apoptosis; D002318:Cardiovascular Diseases / Q000209:etiology / Q000378:metabolism*; D004260:DNA Repair; D045643:DNA Repair Enzymes / Q000378:metabolism / Q000502:physiology; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000652:urine; D004195:Disease Models, Animal; D006973:Hypertension / Q000209:etiology / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D016296:Mutagenesis; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism / Q000502:physiology; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
chemical_list: D000080242:8-Hydroxy-2'-Deoxyguanosine; D010744:Phosphoric Monoester Hydrolases; C078207:8-oxodGTPase; D045643:DNA Repair Enzymes; D003849:Deoxyguanosine