Mechanical properties of rat tibia under high-G environment / 中国组织工程研究

ABSTRACT

BACKGROUND: With the development of Chinese space industry, pilots are exposed to high-G mechanical environment, which will seriously affect their bones. However, as one of the bones that are most prone to fracture, the biomechanical behavior of the tibia under extreme mechanical environment is rarely reported. OBJECTIVE: To explore the effects of different high-G mechanical environments on the rat growth and development and the mechanical properties of the tibia. METHODS: Male Wistar rats were provided by Laboratory Animal Center of Academy of Military Sciences. The cantilever was set to run at different speeds and accelerations with a high-G centrifugal loading device, and the high-G rat model was made. The rats were weighed weekly. The left tibia of rats was used for undergoing a three-point bending experiment, and the deflection and elastic modulus of the tibia were calculated. The right tibia was subjected to a creep test, and constant stress was applied on the surface of tibial cortical bone and kept 3 600 seconds, so as to observe the changes of creep strain. The study was approved by the Laboratory Animal Ethical Committee of Tianjin University of Technology. RESULTS AND CONCLUSION: The high-G environment affected the normal growth and development of rats, inhibited weight gain and reduced the mechanical properties of the tibia, and reduced the limit deflection of the tibia by 8.1%, 12.2%, 37.8%, and 51.4%, respectively. Limit loads were decreased by 16%, 9%, 25.2%, and 29% respectively. To conclude, extremely high-G environment exerts serious negative effects on rats.