Study Of The Thymus Proteomics Of Spaceflight Model Rats

Objective Two rat models of spaceflight environment, which are the stress noise andtail-suspended, were established, respectively, to imitate microgravity and stress noise, toinvestigate change of protein level in thymus of those rats under space conditions, toexplore the relationships between the immune system and stress factors. Based on theabove results, possible effects on immune system of the astronauts were deduced as theywere under microgravity conditions during spaceflight and high frequency of noise whenthey returned to ground.Method 24 Sprague-Dawley (SD) rats were randomly divided into three groups:stress noise exposed, tail-suspended and control group. They were fed in different sur-rounddings, respectively, according to corresponding models, which we wanted to estab-lish. All of the rats were killed and their thymuses were obtained. Total proteins wereseparated by two-dimensional electrophoresis (2-DE), followed by identifition usingmatrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). The mass spectra were searched against the nr database of NCBI using MASCOTsoftware (version 2.2). Taken together, our results provided protein expression profile of ratthymus and differentially expressed proteins between control and stress noise group orcontrol and tail-suspended group, respectively.Results 214, 218, 256 mutual gel spots collected from eight samples in control, stressnoise and tail-suspended group, respectively, were analyzed by imagemaster 5.0 softwareof Amersham. Totally, 201 proteins were identified in rat thymus tissues. There are 36differentially expressed proteins between control and stress noise group, 24 of which areup-regulated proteins and 12 down-regulated proteins under stress noise. These proteinsare in relation to metabolism, signal transduction, enzyme, signal regulation, cytoskeleton,immune, nervous transduction, and ion channel; There are 37 differentially expressed proteins between control and tail-suspended group, which of 24 are up-regulated proteinsand 12 down-regulated proteins between control and tail-suspended group. These protreinsare involved in metabolism, signal transduction, adhere, transcription, apoptosis, tumorsuppression, and so on. The results indcate that influence of spaceflight environment onimmune function and atrophy of thymus gland are consistent with initial prediction.Conclusion Our data show that proteomics technologies could be used in the study ofsome physio-changes change of cosmonauts in spaceflight.