Three Weeks of Anti-orthostatic Suspension had no Effect on Immune Status in a Specific-Pathogen-Free Enfvironment

Abstract

Anti-Orthostatic Suspension (AOS) is a well-known murine ground-based model of simulated microgravity. However, because no commercial equipment is available for AOS in Specific-Pathogen-Free (SPF) laboratories no previous study has been conducted to examine the effect of AOS on allergic immunity. Accordingly, we developed an AOS cage suitable for SPF conditions, and evaluate its reliability and the effect of 3 weeks of AOS on immunity in a mouse model. An AOS cage were developed using stainless steel components. Fourteen female BALB/c mice were allocated to Group A (control group, n=7) or Group B (AOS, n=7). Body weights and thickness of posterior thigh muscles were measured before and after 3 weeks of AOS, and serum IgE and the titers of cytokines (IL-4, IL-5, IL-10, IL-13, and IFN- γ) in bronchoalveolar lavage (BAL) fluid were compared, as were lung histologic findings. The SPF condition was successfully maintained. No significant difference in weight gain was observed between groups A (0.9 ±1.0 g) and B (0.8 ±1.1 g, P>0.05) after the 3-week experimental period. The mean thickness of posterior thigh muscles in Group B was significantly lower than in Group A (0.7 ±0.2 versus -0.4 ±0.3 mm, P =0.001). However, group serum IgE titers, and IL-4, IL-5, IL-10, IL-13, and IFN- γ titers in BAL fluid were non-significantly different. No intergroup difference was found by histopathologic examinations of lungs. In conclusion, using AOS equipment in a SPF laboratory, immune status was not found to be significantly affected by 3 weeks AOS in healthy mice.