[Effects of tumor necrosis factor-α on nutritional status and proteolysis of respiratory muscles in rats with chronic obstructive pulmonary disease].

Objective To investigate the effect of tumor necrosis factor-α(TNF-α) on nutritional status and proteolysis of respiratory muscle in a rat model of chronic obstructive pulmonary disease(COPD).Methods Ninety healthy male adult Wistar rats were randomly divided into model group(A) and normal control group(B).COPD malnutrition rat models were established by cigarettes smoke and nutrient limitation and divided into normal nutrition COPD group(A1),malnutrition COPD group(A2),and malnutrition COPD intervention group(A3).In group A3,the rats received intravenous injection of TNF-α mAb(0.1 mg/kg).TNF-α levels in the serum and respiratory muscle homogenates were measured using enzyme-linked immunosorbent assay(ELISA),and plasma levels of glucose,albumin,and triglyceride were measured with an automatic biochemisty analyzer.High-performance liquid chromatography was used to measure the contents of 3-methylhistidine and tyrosine in the respiratory muscle homogenates.Results The serum TNF-α level and plasma levels of glucose and triglyceride were significantly higher but the plasma albumin level was significantly lower in group A2 than in groups B,A1,and A3(P0.01).The contents of 3-MH and Tyr in the respiratory muscle homogenates were significantly higher in group A2 than in the other 3 groups(P0.01,P0.01).TNF-α in the respiratory muscle showed a strong positive correlation to 3-MH and Tyr.Conclusion TNF-α is one of the causes of increased proteolysis of the respiratory muscle.