title: Changes in intervertebral disc morphology persist 5 mo after 21-day bed rest.
abstract: As part of the nutrition-countermeasures (NUC) study in Cologne, Germany in 2010, seven healthy male subjects underwent 21 days of head-down tilt bed rest and returned 153 days later to undergo a second bout of 21-day bed rest. As part of this model, we aimed to examine the recovery of the lumbar intervertebral discs and muscle cross-sectional area (CSA) after bed rest using magnetic resonance imaging and conduct a pilot study on the effects of bed rest in lumbar muscle activation, as measured by signal intensity changes in T(2)-weighted images after a standardized isometric spinal extension loading task. The changes in intervertebral disc volume, anterior and posterior disc height, and intervertebral length seen after bed rest did not return to prebed-rest values 153 days later. While recovery of muscle CSA occurred after bed rest, increases (P ≤ 0.016) in multifidus, psoas, and quadratus lumborum muscle CSA were seen 153 days after bed rest. A trend was seen for greater activation of the erector spinae and multifidus muscles in the standardized loading task after bed rest. Greater reductions of multifidus and psoas CSA muscle and greater increases in multifidus signal intensity with loading were associated with incidence of low back pain in the first 28 days after bed rest (P ≤ 0.044). The current study contributes to our understanding of the recovery of the lumbar spine after 21-day bed rest, and the main finding was that a decrease in spinal extensor muscle CSA recovers within 5 mo after bed rest but that changes in the intervertebral discs persist.
authors.affiliation: Charité Universitätsmedizin Berlin, Centre of Muscle and Bone Research, Berlin, Germany. belavy@gmail.com
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Belavý
authors.forename: P Martin
authors.initials: PM
authors.lastname: Bansmann
authors.forename: Gisela
authors.initials: G
authors.lastname: Böhme
authors.forename: Petra
authors.initials: P
authors.lastname: Frings-Meuthen
authors.forename: Martina
authors.initials: M
authors.lastname: Heer
authors.forename: Jörn
authors.initials: J
authors.lastname: Rittweger
authors.forename: Jochen
authors.initials: J
authors.lastname: Zange
authors.forename: Dieter
authors.initials: D
authors.lastname: Felsenberg
mesh_terms: D000328:Adult; D001510:Bed Rest; D001639:Bicarbonates / Q000008:administration & dosage; D001862:Bone Resorption / Q000517:prevention & control; D003430:Cross-Sectional Studies; D005858:Germany; D018475:Head-Down Tilt / Q000502:physiology; D006801:Humans; D007403:Intervertebral Disc / Q000033:anatomy & histology / Q000502:physiology*; D017116:Low Back Pain / Q000503:physiopathology*; D008159:Lumbar Vertebrae / Q000033:anatomy & histology / Q000502:physiology*; D008161:Lumbosacral Region / Q000502:physiology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009043:Motor Activity / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology; D010865:Pilot Projects; D017680:Potassium Compounds / Q000008:administration & dosage; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D001639:Bicarbonates; D017680:Potassium Compounds; C026329:potassium bicarbonate