title: Complete lack of vitamin C intake generates pulmonary emphysema in senescence marker protein-30 knockout mice.
abstract: Vitamin C (VC) is a potent antioxidant and plays an essential role in collagen synthesis. As we previously reported, senescence marker protein-30 (SMP30) knockout (KO) mice cannot synthesize VC due to the genetic disruption of gluconolactonase (i.e., SMP30). Here, we utilized SMP30 KO mice deprived of VC and found that VC depletion caused pulmonary emphysema due to oxidative stress and a decrease of collagen synthesis by the third month of age. We grew SMP30 KO mice and wild-type (WT) mice on VC-free chow and either VC water [VC(+)] or plain water [VC(-)] after weaning at 4 wk of age. Morphometric findings and reactive oxygen species (ROS) in the lungs were evaluated at 3 mo of age. No VC was detected in the lungs of SMP30 KO VC(-) mice, but their ROS increased 50.9% over that of the VC(+) group. Moreover, their collagen content in the lungs markedly decreased, and their collagen I mRNA decreased 82.2% compared with that of the WT VC(-) group. In the SMP30 KO VC(-) mice, emphysema developed [21.6% increase of mean linear intercepts (MLI) and 42.7% increase of destructive index compared with VC(+) groups], and the levels of sirtuin 1 (Sirt1) decreased 16.8%. However, VC intake increased the MLI 16.2% and thiobarbituric acid reactive substances 22.2% in WT mice, suggesting that an excess of VC can generate oxidative stress and may be harmful during this period of lung development. These results suggest that VC plays an important role in lung development through affecting oxidant-antioxidant balance and collagen synthesis.
authors.affiliation: Department of Respiratory Medicine, Juntendo Univerity School of Medicine, Tokyo, Japan.
authors.forename: Kengo
authors.initials: K
authors.lastname: Koike
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Kondo
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Sekiya
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Sato
authors.forename: Kazunori
authors.initials: K
authors.lastname: Tobino
authors.forename: Shin-iciro
authors.initials: SI
authors.lastname: Iwakami
authors.forename: Sataro
authors.initials: S
authors.lastname: Goto
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Takahashi
authors.forename: Naoki
authors.initials: N
authors.lastname: Maruyama
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Seyama
authors.forename: Akihito
authors.initials: A
authors.lastname: Ishigami
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000502:physiology*; D001206:Ascorbic Acid Deficiency / Q000150:complications*; D002135:Calcium-Binding Proteins / Q000172:deficiency*; D024042:Collagen Type I / Q000096:biosynthesis; D047908:Intracellular Signaling Peptides and Proteins / Q000172:deficiency*; D008168:Lung / Q000378:metabolism / Q000473:pathology / Q000502:physiology; D051379:Mice; D018345:Mice, Knockout; D018384:Oxidative Stress / Q000502:physiology; D011656:Pulmonary Emphysema / Q000209:etiology* / Q000473:pathology; D017382:Reactive Oxygen Species / Q000378:metabolism; D056564:Sirtuin 1 / Q000096:biosynthesis
chemical_list: D002135:Calcium-Binding Proteins; D024042:Collagen Type I; D047908:Intracellular Signaling Peptides and Proteins; D017382:Reactive Oxygen Species; C513324:Rgn protein, mouse; D056564:Sirtuin 1; D001205:Ascorbic Acid