Learning on Jupiter, learning on the Moon: the dark side of the G-force. Effects of gravity changes on neurovascular unit and modulation of learning and memory

Porte, Yves; Morel, Jean-Luc

doi:10.3389/fnbeh.2012.00064

Cited by 17 publications

(11 citation statements)

References 133 publications

(134 reference statements)

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“…Finally, although the impairment in memory processes in people exposed to WBV are not clearly demonstrated, 32,33 several studies in mice have suggested that alterations of spatial navigation and memory could be induced by gravity changes. 34 This is supported by transcriptomic and proteomic analysis of brain in mice models, 22,35,36 and more recently in humans by magnetic resonance imaging. 4,[37][38][39][40] As also proposed in the field of neurodegenerative disorders, an impairment of the BBB is suggested to induce or accelerate the processes of the memory impairments.…”

Section: Discussionmentioning

confidence: 91%

Effects of centrifugation and whole-body vibrations on blood–brain barrier permeability in mice

et al. 2020

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Modifications of gravity levels induce generalized adaptation of mammalian physiology, including vascular, brain, muscle, bone and immunity functions. As a crucial interface between the vascular system and the brain, the blood-brain barrier (BBB) acts as a filter to protect neurons from pathogens and inflammation. Here we compare the effects of several protocols of hypergravity induced by centrifugation and whole-body vibrations (WBV) on BBB integrity. The immunohistochemistry revealed immunoglobulin G (IgG) extravasation from blood to hippocampal parenchyma of mice centrifuged at 2 × g during 1 or 50 days, whereas short exposures to higher hypergravity mimicking the profiles of spaceflight landing and takeoff (short exposures to 5 × g) had no effects. These results suggest prolonged centrifugation (>1 days) at 2 × g induced a BBB leakage. Moreover, WBV were similarly tested. The short exposure to +2 × g vibrations (900 s/day at 90 Hz) repeated for 63 days induced IgG extravasation in hippocampal parenchyma, whereas the progressive increase of vibrations from +0.5 to +2 × g for 63 days was not able to affect the IgG crossing through the BBB. Overall, these results suggest that the BBB permeability is sensitive to prolonged external accelerations. In conclusion, we advise that the protocols of WBV and centrifugation, proposed as countermeasure to spaceflight, should be designed with progressively increasing exposure to reduce potential side effects on the BBB.

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Section: Discussionmentioning

confidence: 91%

Effects of centrifugation and whole-body vibrations on blood–brain barrier permeability in mice

et al. 2020

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“…It has been reported that the space environment may have adverse effects on physical abilities, mood and cognitive functioning (57,58). To determine whether a chronic, low dose of cobalt-57 radiation, simulated microgravity or a combination of the two affect behavior in mice, we are currently performing behavioral assessments on these animals.…”

Section: Figmentioning

confidence: 99%

Simulated Microgravity and Low-Dose/Low-Dose-Rate Radiation Induces Oxidative Damage in the Mouse Brain

et al. 2016

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Microgravity and radiation are stressors unique to the spaceflight environment that can have an impact on the central nervous system (CNS). These stressors could potentially lead to significant health risks to astronauts, both acutely during the course of a mission or chronically, leading to long-term, post-mission decrements in quality of life. The CNS is sensitive to oxidative injury due to high concentrations of oxidizable, unsaturated lipids and low levels of antioxidant defenses. The purpose of this study was to evaluate oxidative damage in the brain cortex and hippocampus in a ground-based model for spaceflight, which includes prolonged unloading and low-dose radiation. Whole-body low-dose/low-dose-rate (LDR) gamma radiation using (57)Co plates (0.04 Gy at 0.01 cGy/h) was delivered to 6 months old, mature, female C57BL/6 mice (n = 4-6/group) to simulate the radiation component. Anti-orthostatic tail suspension was used to model the unloading, fluid shift and physiological stress aspects of the microgravity component. Mice were hindlimb suspended and/or irradiated for 21 days. Brains were isolated 7 days or 9 months after irradiation and hindlimb unloading (HLU) for characterization of oxidative stress markers and microvessel changes. The level of 4-hydroxynonenal (4-HNE) protein, an oxidative specific marker for lipid peroxidation, was significantly elevated in the cortex and hippocampus after LDR + HLU compared to controls (P < 0.05). The combination group also had the highest level of nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2) expression compared to controls (P < 0.05). There was a significant decrease in superoxide dismutase (SOD) expression in the animals that received HLU only or combined LDR + HLU compared to control (P < 0.05). In addition, 9 months after LDR and HLU exposure, microvessel densities were the lowest in the combination group, compared to age-matched controls in the cortex (P < 0.05). Our data provide the first evidence that prolonged exposure to simulated microgravity and LDR radiation is associated with increased oxidative stress biomarkers that may increase the likelihood of brain injury and reduced antioxidant defense. NOX2-containing nicotinamide adenosine dinucleotide phosphate (NADPH oxidase) may contribute to spaceflight environment-induced oxidative stress.

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“…This hypothesis is supported by the existence of a hypothalamic-pituitary-adrenal axis activation induced by vestibular lesions (Gliddon et al, 2003a , b ). Gravity changes could also alter cognitive function via modulation of brain vascular reactivity (Porte and Morel, 2011 ). In addition, high levels of hypergravity induce severe impairments in cognitive abilities which may be associated with brain ischemia (Sun et al, 2009 ).…”

Section: Effects Of Altered Gravity On the Development Of Gravity Senmentioning

confidence: 99%

The development of vestibular system and related functions in mammals: impact of gravity

Jamon

2014

Front. Integr. Neurosci.

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This chapter reviews the knowledge about the adaptation to Earth gravity during the development of mammals. The impact of early exposure to altered gravity is evaluated at the level of the functions related to the vestibular system, including postural control, homeostatic regulation, and spatial memory. The hypothesis of critical periods in the adaptation to gravity is discussed. Demonstrating a critical period requires removing the gravity stimulus during delimited time windows, what is impossible to do on Earth surface. The surgical destruction of the vestibular apparatus, and the use of mice strains with defective graviceptors have provided useful information on the consequences of missing gravity perception, and the possible compensatory mechanisms, but transitory suppression of the stimulus can only be operated during spatial flight. The rare studies on rat pups housed on board of space shuttle significantly contributed to this problem, but the use of hypergravity environment, produced by means of chronic centrifugation, is the only available tool when repeated experiments must be carried out on Earth. Even though hypergravity is sometimes considered as a mirror situation to microgravity, the two situations cannot be confused because a gravitational force is still present. The theoretical considerations that validate the paradigm of hypergravity to evaluate critical periods are discussed. The question of adaption of graviceptor is questioned from an evolutionary point of view. It is possible that graviception is hardwired, because life on Earth has evolved under the constant pressure of gravity. The rapid acquisition of motor programming by precocial mammals in minutes after birth is consistent with this hypothesis, but the slow development of motor skills in altricial species and the plasticity of vestibular perception in adults suggest that gravity experience is required for the tuning of graviceptors. The possible reasons for this dichotomy are discussed.

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Learning on Jupiter, learning on the Moon: the dark side of the G-force. Effects of gravity changes on neurovascular unit and modulation of learning and memory

Cited by 17 publications

References 133 publications

Effects of centrifugation and whole-body vibrations on blood–brain barrier permeability in mice

Effects of centrifugation and whole-body vibrations on blood–brain barrier permeability in mice

Simulated Microgravity and Low-Dose/Low-Dose-Rate Radiation Induces Oxidative Damage in the Mouse Brain

The development of vestibular system and related functions in mammals: impact of gravity

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