Effect of Tail Suspension (or Simulated Weightlessness) on the Lumbar Intervertebral Disc

Hutton, William; Yoon, S. Tim; Elmer, William A.; Li, Jun; Murakami, Hideki; Minamide, Akihito; Akamaru, Tomoyuki

doi:10.1097/00007632-200206150-00008

Cited by 56 publications

(37 citation statements)

References 15 publications

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“…This might inhibit the metabolism of nucleus pulposus cells and, consequently, produce early degenerative changes in intervertebral disks. Some animal data showed that proteoglycans decreased, and the collagen-to-proteoglycan ratio of intervertebral disks increased in space-flown animals (12,25). No such biochemical and cytological studies are available for human intervertebral disks during microgravity or long-term bed rest, although some studies show that disk height, CSA, and volume all increase (11,15).…”

Section: Discussionmentioning

confidence: 99%

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Exercise within lower body negative pressure partially counteracts lumbar spine deconditioning associated with 28-day bed rest

Cao¹,

Kimura²,

Macias³

et al. 2005

Journal of Applied Physiology

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. Exercise within lower body negative pressure partially counteracts lumbar spine deconditioning associated with 28-day bed rest. J Appl Physiol 99: 39 -44, 2005. First published March 10, 2005; doi:10.1152/japplphysiol.01400.2004.-Astronauts experience spine deconditioning during exposure to microgravity due to the lack of axial loads on the spine. Treadmill exercise in a lower body negative pressure (LBNP) chamber provides axial loads on the lumbar spine. We hypothesize that daily supine LBNP exercise helps counteract lumbar spine deconditioning during 28 days of microgravity simulated by bed rest. Twelve sets of healthy, identical twins underwent 6°head-down-tilt bed rest for 28 days. One subject from each set of twins was randomly assigned to the exercise (Ex) group, whereas their sibling served as a nonexercise control (Con). The Ex group exercised in supine posture within a LBNP chamber for 45 min/day, 6 days/wk. All subjects underwent magnetic resonance imaging of their lumbar spine before and at the end of bed rest. Lumbar spinal length increased 3.7 Ϯ 0.5 mm in the Con group over 28-day bed rest, whereas, in the Ex group, lumbar spinal length increased significantly less (2.3 Ϯ 0.4 mm, P ϭ 0.01). All lumbar intervertebral disk heights (L5-S1, L4-5, L3-4, L2-3, and L1-2) in the Con group increased significantly over the 28-day bed rest (P Ͻ 0.05). In the Ex group, there were no significant increases in L 5-S1 and L4-5 disk heights. Lumbar lordosis decreased significantly by 3.3 Ϯ 1.2°d uring bed rest in the Con group (P ϭ 0.02), but it did not decrease significantly in the Ex group. Our results suggest that supine LBNP treadmill exercise partially counteracts lumbar spine lengthening and deconditioning associated with simulated microgravity. simulated microgravity; lumbar spine length; intervertebral disk height; spinal curvature; countermeasures MANY ANATOMICAL AND PHYSIOLOGICAL changes occur when the human body is exposed to microgravity. These changes include cardiovascular deconditioning, loss of exercise capacity, muscle atrophy, and bone loss. Moreover, there are several reports concerning spine deconditioning during adaptation to microgravity, such as spine lengthening (4, 28, 32), intervertebral disk alterations (15), spine curvature increase (29), and back muscle atrophy (17).Because the lumbar spine normally bears ϳ50% body weight (BW) during upright posture on Earth (14, 22, 23), this portion of the spine may be uniquely adapted to gravity. On Earth after overnight bed rest, lumbar length increases ϳ2.7 mm (15). During spaceflight, 4-to 6-cm increase of body height occurs in astronauts (4, 28, 32). Additionally, intervertebral disk volume and cross-sectional area (CSA) increase during simulated and actual microgravity (11,15). Animal experiments document disk biochemistry and degeneration during microgravity (12,25). Thornton and collaborators (29) found a decrease in spinal curvature with exposing to microgravity. Moreover, LeBlanc and coworkers (17) report that even short-duration spacefligh...

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Section: Discussionmentioning

confidence: 99%

“…Additionally, intervertebral disk volume and cross-sectional area (CSA) increase during simulated and actual microgravity (11,15). Animal experiments document disk biochemistry and degeneration during microgravity (12,25). Thornton and collaborators (29) found a decrease in spinal curvature with exposing to microgravity.…”

mentioning

confidence: 99%

Exercise within lower body negative pressure partially counteracts lumbar spine deconditioning associated with 28-day bed rest

Cao¹,

Kimura²,

Macias³

et al. 2005

Journal of Applied Physiology

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“…This may thereby have an influence on medium to long-term IVD injury risk. Animal models investigating the IVD in spaceflight [48,49], hindlimb suspension [50][51][52][53] and tail vertebra immobilisation [54,55] have typically [48][49][50][51][52][53]55], but not always [54], found losses in glycosaminoglycan content. However, the extent to which animal models can be used as a model of human IVD changes in spaceflight remains an open question [56].…”

Section: Long-term Effect Of Spaceflight On Spinal Tissuesmentioning

confidence: 99%

Disc herniations in astronauts: What causes them, and what does it tell us about herniation on earth?

et al. 2015

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Purpose Recent work showed an increased risk of cervical and lumbar intervertebral disc (IVD) herniations in astronauts. The European Space Agency asked the authors to advise on the underlying pathophysiology of this increased risk, to identify predisposing factors and possible interventions and to suggest research priorities. Methods The authors performed a narrative literature review of the possible mechanisms, and conducted a survey within the team to prioritize research and prevention approaches.Results and conclusions Based on literature review the most likely cause for lumbar IVD herniations was concluded to be swelling of the IVD in the unloaded condition during spaceflight. For the cervical IVDs, the knowledge base is too limited to postulate a likely mechanism or recommend approaches for prevention. Basic research on the impact of (un)loading on the cervical IVD and translational research is needed. The highest priority prevention approach for the lumbar spine was post-flight care avoiding activities involving spinal flexion, followed by passive

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“…AF cells are subjected to a variety of stresses in vivo such as osmotic stress [5] and various mechanical stresses [8,16]. Despite its obvious importance, however, endoplasmic reticulum stress response has not been documented regarding AF cell apoptosis induced by cyclic stretch so far.…”

Section: Introductionmentioning

confidence: 99%

Cyclic stretch-induced apoptosis in rat annulus fibrosus cells is mediated in part by endoplasmic reticulum stress through nitric oxide production

et al. 2011

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Various mechanical stresses in vivo induce disc cell apoptosis and intervertebral disc (IVD) degeneration, but the underlying molecular mechanism is not fully known. The aim of this study was to investigate the role of endoplasmic reticulum stress in cyclic stretch-induced apoptosis of rat annulus fibrosus (AF) cells. Flexercell Tension Plus system was used to apply cyclic stretch to rat annulus fibrosus cells at a frequency of 0.5 Hz with 20% elongation for 12, 24, 36, or 48 h. Apoptosis was detected by flow cytometry, and nuclei morphologic changes were visualized by Hoechst 33258 staining and caspase-8, 9 activity assays. The expression of the markers of endoplasmic reticulum stress including CHOP, GRP78, and caspase-12 were determined by RT-PCR and Western blot. Mitochondrial membrane potential change was observed by JC-1 staining in situ. In addition, the levels of the nitric oxide (NO) were determined with the Griess reaction and fluorescence staining. The results indicated that cyclic stretch at a frequency of 0.5 Hz with 20% elongationinduced apoptosis in rat AF cells. Prolonged exposure of the unphysiologically cyclic stretch to AF cells caused NO overproduction, up-regulation of endoplasmic reticulum stress markers including CHOP, GRP78, and caspase-12, depolarization of mitochondria and activation of caspase-9. However, cyclic stretch at this level had no effect on caspase-8 activity. In addition, specific inhibitor of caspase-12 (Z-ATAD-FMK) and caspase-9 (Z-LEHD-FMK) partly suppressed cyclic stretch-induced AF cell apoptosis and the anti-apoptotic effects of the caspase inhibitors were additive. Our data suggest that endoplasmic reticulum stress, likely mediated by NO, contributes to the AF cell apoptosis induced by cyclic stretch in addition to the mitochondrial pathway. These findings could be helpful to understand the mechanism of disc cell apoptosis, the root cause of IVD degeneration.

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Effect of Tail Suspension (or Simulated Weightlessness) on the Lumbar Intervertebral Disc

Abstract: These findings clearly establish a link between decreased proteoglycan content and tension on the disc, as modeled by the tail-suspended rat.

Cited by 56 publications

References 15 publications

Exercise within lower body negative pressure partially counteracts lumbar spine deconditioning associated with 28-day bed rest

Exercise within lower body negative pressure partially counteracts lumbar spine deconditioning associated with 28-day bed rest

Disc herniations in astronauts: What causes them, and what does it tell us about herniation on earth?

Cyclic stretch-induced apoptosis in rat annulus fibrosus cells is mediated in part by endoplasmic reticulum stress through nitric oxide production

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