Preliminary proteomic analysis of peripheral skeletal muscle atrophy in chronic obstructive pulmonary disease

Objective To conduct a preliminary proteomic study of chronic obstructive pulmonary disease (COPD) with peripheral skeletal muscle atrophy.Methods A total of 16 COPD patients and 8 aged-matched persons because of bone fractures were recruited in First Hospital Affiliated to Kunming Medical College from February to July in 2010. According to body mass index,fat free mass index,quadriceps femoris perimeter and quadriceps femoris active contraction,they were divided into those with muscle atrophy (group A,n=8) and those without (group B,n=8).There were 6 males and 2 females with an average age of (70±8) years in the group A and 5 males and 3 females with an average age of (74±8) years in the group B. And the control group had 6 males and 2 females with an average age of (72±6) years.All samples of total quadriceps protein were separated by two-dimensional gel electrophoresis.The abnormal protein points on electrophoresis were compared by PDQuest image software.And the differential protein expression was detected. Then the corresponding peptide quality fingerprint spectrum was analyzed by mass spectrometer.Finally the differential protein points were partially detected by a search of database.Results The two-dimensional gel electrphoresis yielded an excellent profile of resolution and repeatability.And 12 proteins likely to cause skeletal muscle atrophy in COPD were identified.Among them,8 proteins belonged to structural proteins (actin alpha cardiac muscle isoform CRA_c,myosin regulatory light chain 2,ventricular/cardiac muscle isoform,myoglobin isoform myosin heavy polypeptide 7 cardiac muscle beta isoform CRA_c,actin,alpha skeletal muscle,actin alpha cardiac muscle isoform CRA_b,hemoglobin alpha 1 globin chain & myosin light chain 6B) and 4 proteins were of functional proteins (chain A,crystal structure of human enolase ; troponin T,slow skeletal muscle isoform alpha,carbonate anhydrase,troponin T & slow skeletal muscle isoform b).Conclusions COPD patients are often accompanied with obvious peripheral skeletal muscle atrophy. It may be caused by quantitative or qualitative changes of peripheral skeletal structural and functional proteins. Key words: Pulmonary disease ,chronic obstructive;  Muscle, skeletal;  Proteomics;  Peptide mapping