title: Spaceflight affects postnatal development of the aortic wall in rats.
abstract: We investigated effect of microgravity environment during spaceflight on postnatal development of the rheological properties of the aorta in rats. The neonate rats were randomly divided at 7 days of age into the spaceflight, asynchronous ground control, and vivarium control groups (8 pups for one dam). The spaceflight group rats at 9 days of age were exposed to microgravity environment for 16 days. A longitudinal wall strip of the proximal descending thoracic aorta was subjected to stress-strain and stress-relaxation tests. Wall tensile force was significantly smaller in the spaceflight group than in the two control groups, whereas there were no significant differences in wall stress or incremental elastic modulus at each strain among the three groups. Wall thickness and number of smooth muscle fibers were significantly smaller in the spaceflight group than in the two control groups, but there were no significant differences in amounts of either the elastin or collagen fibers among the three groups. The decreased thickness was mainly caused by the decreased number of smooth muscle cells. Plastic deformation was observed only in the spaceflight group in the stress-strain test. A microgravity environment during spaceflight could affect postnatal development of the morphological and rheological properties of the aorta.
authors.affiliation: Department of Cellular and Integrative Physiology, Fukushima Medical University, 1 Hikari-ga-oka, Fukushima 960-1295, Japan.
authors.forename: Shin-ichiro
authors.identifier: 0000-0003-1134-5592
authors.initials: S
authors.lastname: Katsuda
authors.affiliation: Department of Cellular and Integrative Physiology, Fukushima Medical University, 1 Hikari-ga-oka, Fukushima 960-1295, Japan ; Department of Physiology, Faculty of Clinical Engineering, School of Health Sciences, Fujita Health University, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470-1192, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Yamasaki
authors.affiliation: Department of Cellular and Integrative Physiology, Fukushima Medical University, 1 Hikari-ga-oka, Fukushima 960-1295, Japan ; School of Health and Sports Science, Juntendo University, 1-1 Hiragagakuendai, Inzai, Chiba 270-1695, Japan.
authors.forename: Hidefumi
authors.initials: H
authors.lastname: Waki
authors.affiliation: Department of Cellular and Integrative Physiology, Fukushima Medical University, 1 Hikari-ga-oka, Fukushima 960-1295, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Miyake
authors.affiliation: Department of Cellular and Integrative Physiology, Fukushima Medical University, 1 Hikari-ga-oka, Fukushima 960-1295, Japan ; Medical Corporations Tenshindo Shida Hospital, 2134-4 Oaza-Nakamura, Kashima, Saga 849-1304, Japan.
authors.forename: Hirotaka
authors.identifier: 0000-0002-0089-7431
authors.initials: H
authors.lastname: O-ishi
authors.affiliation: Medical-Industrial Translational Research Center, Fukushima Medical University, 1 Hikari-ga-oka, Fukushima 960-1295, Japan.
authors.forename: Kiyoaki
authors.identifier: 0000-0002-3838-886X
authors.initials: K
authors.lastname: Katahira
authors.affiliation: Department of Cellular and Integrative Physiology, Fukushima Medical University, 1 Hikari-ga-oka, Fukushima 960-1295, Japan ; Nihonmatsu Hospital, 1-553 Narita-cho, Nihonmatsu, Fukushima 964-0871, Japan.
authors.forename: Tadanori
authors.initials: T
authors.lastname: Nagayama
authors.affiliation: Department of Cellular and Integrative Physiology, Fukushima Medical University, 1 Hikari-ga-oka, Fukushima 960-1295, Japan.
authors.forename: Yukako
authors.initials: Y
authors.lastname: Miyamoto
authors.affiliation: National Cerebral and Cardiovascular Center Research Institute, 5-7-1 Fujishiro-dai, Suita, Osaka 565-0873, Japan.
authors.forename: Masamitsu
authors.identifier: 0000-0002-2112-8877
authors.initials: M
authors.lastname: Hasegawa
authors.affiliation: Department of Cellular and Integrative Physiology, Fukushima Medical University, 1 Hikari-ga-oka, Fukushima 960-1295, Japan.
authors.forename: Haruyuki
authors.initials: H
authors.lastname: Wago
authors.affiliation: Department of Cellular and Integrative Physiology, Fukushima Medical University, 1 Hikari-ga-oka, Fukushima 960-1295, Japan.
authors.forename: Toshiyasu
authors.initials: T
authors.lastname: Okouchi
authors.affiliation: Department of Cellular and Integrative Physiology, Fukushima Medical University, 1 Hikari-ga-oka, Fukushima 960-1295, Japan ; Shimizu Institute of Space Physiology, Suwa Maternity Clinic, 112-13 Shimosuwa, Suwa-gun, Nagano 393-0077, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Shimizu
mesh_terms: D000818:Animals; D001011:Aorta / Q000254:growth & development*; D004548:Elasticity; D004622:Embryo, Mammalian; D047108:Embryonic Development; D032389:Myocytes, Smooth Muscle / Q000502:physiology*; D051381:Rats; D012212:Rheology; D013026:Space Flight