Noriaki Kawanishi1,2,3,4, Tomoko Funakoshi1,5, Shuichi Machida1,3. 1. Graduate School of Health and Sports Science, Juntendo University, 1-1 Hirakagakuendai, Inzai, 270-1695, Japan. 2. Japan Society for the Promotion of Sciences, Tokyo, Japan. 3. Institute of Health & Sports Science and Medicine, Juntendo University, Inzai, Japan. 4. Faculty of Advanced Engineering, Chiba Institute of Technology, Narashino, Japan. 5. Molecular Regulation of Aging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
Abstract
INTRODUCTION: Macrophage infiltration may play an important role in mediating the development of muscle atrophy. However, temporal differences in the activation of muscle atrophy signaling pathways and the progress of macrophage infiltration during the atrophic phases of cast immobilization are currently unknown. METHODS: C57BL/6J mice were euthanized after cast immobilization at 1, 3, 7, and 14 days. RESULTS: Skeletal muscle macrophage numbers were unchanged on days 1 and 3 after immobilization, but were elevated on days 7 (2.7-fold, P < 0.01) and 14 (4.1-fold, P < 0.01). Ubiquitin ligase expression was increased 1 and 3 days after cast immobilization, as was the LC3-II/LC3-I ratio. DISCUSSION: Atrophy signaling pathway activation, but not macrophage infiltration, was observed during the early phase after cast immobilization. Our findings indicate that macrophage infiltration may contribute very little to the early phase of muscle atrophy after cast immobilization. Muscle Nerve 57: 1006-1013, 2018.
INTRODUCTION: Macrophage infiltration may play an important role in mediating the development of muscle atrophy. However, temporal differences in the activation of muscle atrophy signaling pathways and the progress of macrophage infiltration during the atrophic phases of cast immobilization are currently unknown. METHODS: C57BL/6J mice were euthanized after cast immobilization at 1, 3, 7, and 14 days. RESULTS: Skeletal muscle macrophage numbers were unchanged on days 1 and 3 after immobilization, but were elevated on days 7 (2.7-fold, P < 0.01) and 14 (4.1-fold, P < 0.01). Ubiquitin ligase expression was increased 1 and 3 days after cast immobilization, as was the LC3-II/LC3-I ratio. DISCUSSION: Atrophy signaling pathway activation, but not macrophage infiltration, was observed during the early phase after cast immobilization. Our findings indicate that macrophage infiltration may contribute very little to the early phase of muscle atrophy after cast immobilization. Muscle Nerve 57: 1006-1013, 2018.
Authors: Paul T Reidy; Alec I McKenzie; Ziad S Mahmassani; Jonathan J Petrocelli; Daniel B Nelson; Catherine C Lindsay; James E Gardner; Vincent R Morrow; Alexandra C Keefe; Thomas B Huffaker; Greg J Stoddard; Gabrielle Kardon; Ryan M O'Connell; Micah J Drummond Journal: Am J Physiol Endocrinol Metab Date: 2019-04-09 Impact factor: 4.310
Authors: Paul T Reidy; Nikol M Yonemura; Jared H Madsen; Alec I McKenzie; Ziad S Mahmassani; Matthew T Rondina; Yu Kuei Lin; Katie Kaput; Micah J Drummond Journal: Acta Physiol (Oxf) Date: 2019-01-30 Impact factor: 7.523