There were significantly increased levels of miR-23a, miR-206, and miR-499 in serum of HDBR participants after 45 days of head-down bed rest.
Abbreviations HDBR: Head-down bed rest MRI: Magnetic resonance imaging HU: Hindlimb unloading CSAs: Cross section areas DMD: Duchenne Muscular Dystrophy ALS: Amyotrophic Lateral Sclerosis.
Mano, "Muscle sympathetic nerve activity (MSNA) after 120 days of 6 degrees head-down bed rest (HDBR)," Environmental Medicine, vol.
Caption: Figure 4: Serum miRNAs levels in subjects following HDBR. (a-f) Serum levels of miR-1/23a/133/206/208b/499 in participants before and during HDBR were determined by real-time PCR.
(a-c) The correlation between miR- 23a (a), miR-206 (b), miR-499 (c) levels, and the ratio of soleus volume loss in 15 HDBR participants.
Head-down bed rest (HDBR) is commonly used as a model for microgravity exposure.
As in spaceflight both exposure to HDBR and DI resulted in an increase in height.
Therefore, this measure was conducted before and after DI and HDBR to determine the global restriction of movement, which is characteristic in the manual approach of assessing vertebral dysfunction.
Subjects in both simulations of microgravity (DI and HDBR) developed back pain [33, 34], but with different characteristics.
In HDBR (personal data) the majority of VD was located in crania-cervical (21% in C0-C2) and lumbar (16% in L2-L4) regions.
Additionally, back pain developed during DI was different from HDBR suggesting that vertebral deconditioning is dependent on the simulation model used.
Future work should be conducted to investigate the possibility of a vertebral manual treatment before or during the two models of microgravity exposure (HDBR and DI) as a countermeasure to decrease some effects of vertebral deconditioning.