Protective And Therapeutic Effect Of L-Arginine On The Experimental Chronic Obstructive Pulmonary Disease In Rats

[Objective] To investigate the protective and therapeutic effects of L-Arginine in the pathogenesis of chronic obstructive pulmonary disease (COPD) in rats.[Methods ] COPD animal model was established by smoke inhalations and intratracheal instillations of lipopolysaccharide in Wistar rats. Thirty Wistar rats were randomly divided into 3 groups as follows: normal group(N), control group(C),and treatment group(T) .The last two groups received smoke inhalations daily for 1 month and received intratracheal instillations of lipopolysaccharide twice, one of which received L-Arginine treatment(100mg/Kg BW) daily transesophageally before exposure to cigarette smoking. Lung function test> blood gas analysis , light microscopy and electromicroscopy observations were performed in each group. Pulmonary mean linear intercept (MLI), mean alveolar numbers (MAN), and pulmonary alveolar area (PAA) was measured by image analysis. The expression of eNOS and iNOS were observed by immunohistochemistry. The concentration of NO and NOS in lung tissue homogenate were measured by Nitrate reductase transformation.[Results] Smoking for 1 months and instillations of lipopolysaccharide twice resulted in chronic bronchitis and emphysema. MLI and PAA increased and MAN decreased in the two experimental groups compared with in the normal group (P < 0.01).FEV0.3 and FEV0.3/FVC decreased and Re increased in the two experiment groups compared with in the normal group (P<0.01).PaO2 decreased and PaCO2 increased in the two experimental groups compared with in the normal group. The expression of iNOS increased and the eNOS decreased in the two experimental groups compared with in the normal group(P<0.01).The concentration of the NO and NOS in lung tissue homogenate in three groups were not significantly different(P>0.05). Administration of L-arginine for 1 month resulted in statistically significant inhibition of pulmonary injury. MLI and PAA decreased and MAN increased in T compared with in C(P<0.01).The lung function was improved in T compared with in C(P<0.01): FEV0.3 and FEV0.3/FVC increased and Re decreased in T, also the PaO2 increased and PaCO2 decreased.[Concluson ] L- argnine may have a protective effect on COPD model of rats by alleviating airway inflammatory reaction and improving the lung function .