The Function Of MyoD Protein In The Diaphragm Muscle In Chronic Obstructive Pulmonary Disease And Its Relationship With IGF-1

Objective:Through exploring whether the mechanism of COPD diaphragmatic muscle atrophy associated with MyoD protein content, and to explore the correlation between IGF1and MyoD protein.Methods:70healthy Wister rats were randomly divided into the COPD model group (n=35) and the control group (n=35).The establishment of the rat COPD model:The COPD rats model were established by intratracheal instillation of PPE(20u/100g. Bw) and being exposed to cigarettes smoke for104days,30minutes per day The normal control group was not exposed to cigarettes smoke but was in intratracheal instilled of the same amount of Saline on the same day.104days later, Two groups of rats were examined the lung function, then we took the rats’middle lobe of the right lung and the diaphragm muscle to fixing and pathological section。Both of the tissues were HE stained to he observed the pathological changes by light microscopy And the diaphragm muscle were further tested by immunohistochemical method for the detection to quantitative expression of MyoD protein and IGF-1--1protein and their correlation study. All results are applied SPSS17.0software for statistical analysis.Result:1. COPD model group rats lung function significantly decreased compared with control group, COPD model group rats FEV0.3and FEV0.3/FVC lower than the control group, RI higher than the control group, there are statistically significant. Lung function of the normal control group showed no significant abnormality.2. HE lung tissue staining show:COPD model group rats tissue show Lung tissue injury and inflammation infiltration, pulmonary bulla formation, inflammatory cells infiltration;The control group rats lung tissue HE staining did not see obvious structural abnormalities and inflammatory infiltration.3. COPD group of rat diaphragm muscle fiber area and the number of nuclei per unit area was reduced than control group.4. Immunohistochemical results show:In COPD group, Atrogin-1expression and IGF-1expression was significantly lower than the expression in normal control group.5. The COPD model group rats’diaphragm MyoD expression was positively correlated with the expression of IGF-1.Conclusion:1. MyoD and IGF-1expression reduce may be one of the mechanisms of COPD diagram shrinking.2. MyoD expression was positively correlated with the expression of IGF-1.