Table 2 Advantages and disadvantages of microgravity simulation techniques.
From: The effects of microgravity on bone structure and function
Technique | Advantages | Disadvantages | Reference |
|---|---|---|---|
HBR/HDT (human) | • Fluid redistribution similar to µG • Robust body of work • Enables examination of multiple body systems • Suitable for long-term studies | • Gravitational force on bodyweight is not lost • Compression of skin surface against bed does not occur in true µG • Seven-fold reduction in microgravitational effect compared to dry immersion | Tomilovskaya et al.53 |
HLU (rodents) | • Fluid redistribution similar to µG • Robust body of work • Enables examination of multiple body systems • Suitable for long-term studies | • Internal organs still subjected to gravity | Tesch et al.54 |
Water immersion (human) | • Robust body of work • Enables examination of multiple body systems • Useful in astronaut training | • Imbalance of µG across limbs • Side effects on osmotic balance from immersion • Not suitable for long-term studies | Duddy et al.50 Tsai and Maibach51 |
Dry immersion (human) | • Robust body of work • Enables examination of multiple body systems • Useful in astronaut training | • Imbalance of µG across limbs | Shulzhenko et al.52 Tomilovskaya et al.53 |
RWV (cells) | • Robust body of studies • Well-established method • Near true µG • Varying rotation speeds available | • Susceptible to shear forces and vibration • Potential centrifugal force on samples distant from rotation axis • Formation of multicellular spheroids/cell aggregates • Fast rotating clinostats cannot house large or many samples • For long-term studies, media change requires pausing rotation • Not applicable for examining acute responses to µG | Brungs et al.59 Krause et al.60 Svejgaard et al.62 Loon63 Wuest et al.64 |
RPM (cells) | • Robust body of studies – but less than RCC/RWV • Near true µG • Programmable to simulate gravity of any planet | • Susceptible to shear forces and vibration • Samples further away from centre stage experience centrifugal force • Tendency for multicellular aggregate formation in non-adherent cell samples • Pause in rotation required for media change in long-term studies • Not applicable for examining acute responses to µG | Brungs et al.59 Krause et al.60 Svejgaard et al.62 Loon63 Wuest et al.64 |
Freefall machine (cells) | • Designed to measure acute responses to µG | • Short window of µG • Adverse effects during hyper-gravity window in between falls • Small body of work | Schwarzenberg et al.57 Mesland et al.56 |
