Evaluation of rodent spaceflight in the NASA animal enclosure module for an extended operational period (up to 35 days)

Abstract

The National Aeronautics and Space Administration Animal Enclosure Module (AEM) was developed as a self-contained rodent habitat for shuttle flight missions that provides inhabitants with living space, food, water, ventilation, and lighting, and this study reports whether, after minimal hardware modification, the AEM could support an extended term up to 35 days for Sprague-Dawley rats and C57BL/6 female mice for use on the International Space Station. Success was evaluated based on comparison of AEM housed animals to that of vivarium housed and to normal biological ranges through various measures of animal health and well-being, including animal health evaluations, animal growth and body masses, organ masses, rodent food bar consumption, water consumption, and analysis of blood contents. The results of this study confirmed that the AEMs could support 12 adult female C57BL/6 mice for up to 35 days with self-contained RFB and water, and the AEMs could also support 5 adult male Sprague-Dawley rats for 35 days with external replenishment of diet and water. This study has demonstrated the capability and flexibility of the AEM to operate for up to 35 days with minor hardware modification. Therefore, with modifications, it is possible to utilize this hardware on the International Space Station or other operational platforms to extend the space life science research use of mice and rats.

Global transcriptomic analysis suggests carbon dioxide as an environmental stressor in spaceflight: A systems biology GeneLab case study

“…On the other hand, there have been no studies explicitly comparing stress responses at specific tissue levels for vivarium-housed controls. Chronic low-grade stress in AEM would be consistent both with increased systemic inflammation and reduced thymus 45 . However, contrary to the “stress hypothesis”, AEM allows housing more mice per cage, and higher housing density in mice tends to be associated with lower heart rate and other signs of reduced stress 46 .…”

“…Although prior studies have analyzed behavioral and physiological responses in AEM housing, our study is the first to compare rodent adaptation to spaceflight-matched and standard ground environment at the transcriptional level 45 . A recent comparison of anatomical and physiological parameters of mice and rats housed in AEM and vivarium cages on ground (without a matching flight experiment) 45 indicated physiological changes associated with immune and metabolic functions. For example, AEM-housed rodents had enlarged spleens and increased cholesterol.…”

Inhibition of myostatin prevents microgravity-induced loss of skeletal muscle mass and strength

“…One day prior to launch, flight and ground control animals were injected subcutaneously (SQ) with control IgG (Flight IgG) or YN41 myostatin antibodies (Flight YN41) at 20 mg/kg in a total dosing volume of 200 μl prior to loading into the transportation habitat. YN41 treated mice were loaded into one side of the Transporter housing system [29] and IgG mice into the other side (n = 10 mice/side); ground controls were similarly loaded into a NASA mouse Transporter. The Transporter habitat was loaded into the Space-X Dragon capsule and launched into low Earth orbit on the CRS-8 mission on April 8 th , 2016.…”

Exploring the Effects of Spaceflight on Mouse Physiology using the Open Access NASA GeneLab Platform

“…These include the impact of spaceflight on the muscle structure 16,17,18 and immune functions 19,20,21 . The standard vivarium cages used for housing rodents on Earth are not suitable for spaceflight experiments 22,23 . Therefore, over the years mice and rats have been flown and housed in various cages including the Japanese Aerospace Exploration Agency (JAXA) Habitat Cage 24 , animal carrying space capsules used on the BION-M1 unmanned Russian satellite 25,26,27 , the Mice Drawer System (MDS) designed by the Italian Space Agency 28,29,30 , the NASA Animal Enclosure Module (AEM), and now the NASA Rodent Transporter and Habitats…”

“…The AEM was originally developed for relatively short experiments on-board the shuttle (< 20 days). Since the development of the ISS, the AEMs have been modified for longer duration experiments and are now referred to as Rodent Habitats 22,23 . The new Rodent Habitats are designed to support long-duration missions in the ISS using the EXpedite the PRocessing of Experiments for Space Station (EXPRESS) Rack interface.…”