Exposure to microgravity for 30 days onboard Bion M1 caused muscle atrophy and decreased regeneration in murine femoral Quadriceps

Publication date: Available online 24 August 2017 Source:Life Sciences in Space Research Author(s): E.A. Radugina, E.A.C. Almeida, E. Blaber, V.A. Poplinskaya, Y.V. Markitantova, E.N. Grigoryan Mechanical unloading in microgravity during spaceflight is known to cause muscular atrophy, changes in muscle fiber composition, gene expression, and reductions in regenerative muscle growth. Although some limited data exists for long-term effects of microgravity in human muscle, these processes have mostly been studied in rodents for short periods of time. Here we report on how long-term (30-day long) mechanical unloading in microgravity affects murine muscles of the femoral Quadriceps group. To conduct these studies we used muscle tissue from 6 microgravity mice, in comparison to habitat (7), and vivarium (14) ground control mice from the NASA Biospecimen Sharing Program conducted in collaboration with the Institute for Biomedical Problems of the Russian Academy of Sciences, during the Russian Bion M1 biosatellite mission in 2013. Muscle histomorphology from microgravity specimens shows signs of extensive atrophy and regenerative hypoplasia relative to ground controls. Specifically, we observed a two-fold decrease in the number of myonuclei and their central location, low density of myofibers in the tissue, and of myofibrils within a fiber, as well as fragmentation and swelling of myofibers. Despite obvious atrophy, muscle regeneration nevertheless appears to have continued a...
Source: Life Sciences in Space Research - Category: Biology Source Type: research