Rodent Research in Space: A Scientific Journey into the Unknown
Sometimes research takes us into realms we never anticipated, and require us to quickly become proficient in new techniques/skills. Below we provide insight into a few of the new skills we learned while preparing for our spaceflight studies.
Written by Melissa Kacena and Sue Samson
Question: What do you get when you cross a team of Orthopaedic research scientists with a NASA bone-healing experiment?
Answer: A collection of animal behaviorists, tattoo artists, and graphic designers, of course!
In all seriousness, 17 Indiana University researchers and students had the remarkable opportunity to work with other scientists/engineers/professionals from the US Army, the DOD Space Test Program, and NASA on a spaceflight study that resulted in our publication in npj Microgravity entitled Skeletal Adaptations in Young Male Mice after Four Weeks Aboard the International Space Station. During this project our research led us into realms we never anticipated and required us to quickly become proficient in several new techniques/skills.
Because our rodent study was sending 40 male mice to the ISS for 4 weeks we needed to resolve several ‘first times’ related to housing the rodents. Specifically, we were going to cohouse male mice (prior NASA research in space used only cohoused female mice) and place them in high density housing for approximately 1 week (while they were in the NASA Transporter hardware). We needed scientific validation that the mice would not exhibit increased aggression in this housing scenario. And this is how 17 Indiana University Orthopaedic researchers became animal behaviorists…we studied normal mouse behavior and potential triggers of aggressive behavior, devised a video recording system to constantly monitor mouse activity, worked with veterinarian staff to develop and validate an elaborate behavioral assessment scoring system, learned to recognize mouse behaviors and postures, and analyzed hundreds of hours of video recordings.
On the ground, we identify mice from different groupings by implanting a microchip, notching their ears, or adding a tag to the ears. Each methods has advantages and disadvantages, but for spaceflight studies additional considerations are required, especially if astronauts need to quickly confirm whether the 'correct' mouse is being examined. For example, a microchip requires a chip reader onboard the ISS and unfortunately some microchips may slip out of place. Ear tags can be pulled off by the mice or hook on the wire caging. And ear notching is difficult to visualize especially if the mouse is moving around. This becomes problematic for astronauts wearing cumbersome sleeves and gloves in the microgravity science glovebox system (NASA’s version of a biosafety cabinet/sterile hood). Therefore, we needed to devise a new mouse ID system that was quick and easy. And this is how 17 Indiana University Orthopaedic researchers became tattoo artists…we learned all about tattoo tools and inks, tested a multitude of colors to find what works best on C57BL/6 mouse tails, and honed our tattoo skills by first practicing on oranges and then mouse carcasses. Finally we moved to live mice who were under anesthesia at the time of surgery.
NASA encourages each research team to design an official patch for the space mission, and we embraced that task with enthusiasm. And this is how 17 Indiana University Orthopaedic researchers became graphic designers…we contacted Doug Kacena, Dr. Kacena’s brother, who is an abstract painter and worked with him to design the Rodent Research IV patch displaying a mouse silhouette, a DNA strand, and the SpaceX dragon capsule floating in the stars.
As scientists we never know where the science will take us, which was certainly true as we worked to complete our rodent's journey into space.
Link to our full article in npj Microgravity.
Link to our lab's blog about other spaceflight research adventures, Bone Healing in Space.