Expression profiling of soleus muscle under the effect of simulated spaceflight

Spaceflight imposes the risk of skeletal muscle atrophy for astronauts. The understanding of muscle atrophy because of spaceflight is limited, but continued efforts are essential for developing countermeasures of this effect. A distinct difference between spaceflight-induced muscle atrophy and other forms of atrophy is the additional effect of cosmic rays in outer space. To study spaceflight-induced muscle atrophy, we performed two ground-based models of microgravity in a low dose radiation environment and studied transcriptional changes in rat soleus muscle using microarray technology. Rats (Rattus norvegicus) were divided into the following groups consisting of six rats each and were treated accordingly: 1) Group Ct (continuous irradiation for 2 weeks with a total absorbed dose of 50 mSv); 2) Group TS (tail suspension, and irradiation as in group Ct ); and 3) Group DN (denervation, and irradiation as in group Ct). Rats were anesthetized and their soleus muscles were isolated. Total RNA was isolated from individual frozen tissue and RNA pools were prepared for each group. Gene expression profiling were done using two GeneChip@ Rat Gene 1.0 ST arrays.