Mimic Spaceflight: Microgravity Induces Bone Injury

Abstract

Astronauts take the risk of health problems during spaceflight. One of the most severe problems is bone injury. Though astronauts experience exercises before spaceflight, bone injury is still induced by anti-gravity. To try best to mimic the condition free from the force of gravity, most studies have explored the mechanism of bone injury under microgravity condition. In microgravity environment, osteocytes, osteoclasts, osteoblasts, and mesenchymal stem cells are all identified to alter, contributing to bone loss and function defects of mineralization. Ulteriorly, three typical molecular regulatory pathways including NF-κB pathway, RhoA/integrin pathway, and calcium pathway have been discovered till now, which reveals the possible molecular mechanism. In this article, the specific alterations of cells associated with bone and the three pathways mentioned above will be presented. Different systems are found to related to bone alterations modulated by microgravity as well. So far, the mechanism has not been completely comprehended because of its complexity. However, the current discoveries about mechanism are still valuable. According to regulatory mechanism, new therapies are designed to improve bone injury aiming to help astronauts.