Abstract: Objective: To investigate the effect of moderate-intensity aerobic exercise on the differential expression of rat atrial muscle Proteomics and genes, which provide research basis for the rehabilitation of chronic cardiovascular diseases and exercise -induced cardiac remodeling research. Methods: Twenty male SD rats were randomly divided into control group and experimental group (n=10) according to body weight. Rats in the experimental group were trained (6 days per week),which lasted for 4 weeks of moderate-intensity aerobic exercise at a rate of 24 m·min^-1 for 40 min (load intensity equivalent to 60%~70% VO_2max). The proteins were separated by two dimensional gel electrophoresis, and the tandem time-of- flight mass spectrometer technique was used to identify 13 candidate target protein spots. The expression levels of these 13 protein spots were up-regulated more than 5 times or down -regulated to below 1/5. The mRNA of six target proteins were detected by reverse transcription-polymerase chain reaction (RT-PCR).Results: By software analysis, the experimental group compared with the control group, there were 8 protein points which their expression reduced more than 4/5 and 5 protein points up-regulated more than 5 times, 13 proteins were identified by mass spectrometry protein spots, the final identification results acquired 8 proteins and a unknown protein of molecular mass 54 KDa, such as:pyruvate dehydrogenase E1α1, mitochondrial aconitate hydratase, protein disulfide isomerase A3, methylmalonic acid semialdehyde dehydrogenase, mitochondrial dihydrolipoic acid dehydrogenase, isovaleryl coenzyme A dehydrogenase, glutathione synthetase, mitogen-activated protein kinase 3 and so on. Compared with the control group, the mRNA expression of methylmalonic acid semialdehyde dehydrogenase in the atrial muscle of rats was decreased after 4 weeks of moderate aerobic exercise (P<0.05), the mRNA expression levels of mitochondria Ⅱ lipoic acid dehydrogenase, protein disulfide isomerase A3, mitochondrial aconitate hydratase and glutathione synthetase were decreased (P>0.05); The mRNA expression level of isopentenyl-CoA dehydrogenase was increased (P>0.05). The results indicated that the mRNA expression level was not completely consistent with the changes in mass spectrometry identification results. Conclusion: The 4 weeks moderate-intensity aerobic exercise induced ignificant changes of rats atrial muscle protemics. The majority of the 13 identified target proteins in this experiment are energy metabolism enzymes. The majority of the expression of the target protein and the mRNA expression in the atrial muscle is inconsistent and different. Exercise may affect the regulation of gene transcription or downstream translation and modification of these target proteins, resulting in the change of differential expression.

Key words: proteomics, aerobic exercise, rat, myocardial energy metabolism, mass spectrometry 2-DE