Novel method for evaluating the health condition of mice in space through a video downlink

Abstract

Clarification of the criteria for managing animal health is essential to increase the reliability of experiments and ensure transparency in animal welfare. For experiments performed in space, there is no consensus on how to care for animals owing to technical issues, launch mass limitation, and human resources. Some biological processes in mammals, such as musculoskeletal or immune processes, are altered in the space environment, and mice in space can be used to simulate morbid states, such as senescence acceleration. Thus, there is a need to establish a novel evaluation method and evaluation criteria to monitor animal health. Here, we report a novel method to evaluate the health of mice in space through a video downlink in a series of space experiments using the Multiple Artificial-gravity Research System (MARS). This method was found to be more useful in evaluating animal health in space than observations and body weight changes of the same live mice following their return to Earth. We also developed criteria to evaluate health status via a video downlink. These criteria, with "Fur condition" and "Respiratory" as key 12 items, provided information on the daily changes in the health status of mice and helped to identify malfunctions at 13 an early stage. Our method and criteria led to the success of our missions, and they will help establish appropriate 14 rules for space experiments in the future.

Nrf2 plays a critical role in the metabolic response during and after spaceflight

“…One is that a system for monitoring mouse food consumption and water drinking coupled with single cage housing technology has been developed to precisely analyse mouse metabolism during spaceflight 24 , 30 . The other is that a video downlink system has been developed for veterinarians to monitor real-time mouse health conditions 31 . Although we reported the preliminary results of the plasma metabolome analysis of five metabolites in our initial report 24 , we wished to conduct a more comprehensive study of the metabolic responses during spaceflight.…”

Lunar gravity prevents skeletal muscle atrophy but not myofiber type shift in mice

“…The environmental parameters and habitation data are summarized in Supplementary Information 1 , Supplementary Tables 1 and 2 . In each mission, the health of each mouse was monitored daily by veterinarians on the ground via a downlinked video system 29 . Three representative mice from each group are shown in Supplementary Movie 1 .…”

Gene expression changes related to bone mineralization, blood pressure and lipid metabolism in mouse kidneys after space travel

“…We previously analyzed gene expression and metabolite levels in Nrf2-deficient mice 2 days after return from a 31-day stay in the International Space Station (ISS). 22,23 This project (Mouse Habitat Unit-3 ) demonstrated that lipid metabolism varies during and after spaceflight and that Nrf2 is activated in various organs and is involved in weight gain after the return to Earth. 22 In the present study, using kidney samples from the MHU-3 project, we examined the roles of Nrf2 in kidney functions related to adaptation to space travel.…”

“…The details regarding the space travel of the mice have been published previously. 22,23 After a 31-day stay in the ISS, the mice were returned to Earth with the Dragon vehicle. For ground control samples, mice were individually housed in the same way as for the space travel experiments at JAXA (Tsukuba).…”