An Experimental Study Of The Level Of Calcitonin Gene-related Peptide In Venous Blood And In Bronchoalveolar Lavage Fluid And The Expression Of Calcitonin Gene-related Peptide In The Lung Of Asthmatic Rats

Objective To explore the role of calcitonin gene-related peptide(CGRP) in the pathogenesy of asthma by an experimental study of the concentration of CGRP in venous blood and in bronchoalveolar lavage fluid(BALF)and the expression of CGRP in the lung of asthmatic rats.Methods SD rats were sensitized and challenged with ovalbumin to establish an asthmatic model. There were 10 rats as asthma group and 7 rats as control group. The venous blood and the BALF were collected.Pathological section of the lungs was made and cell composition in the BALF was detected by HE staining. The concentration of CGRP in blood and in BALF was assayed by ELISA. The change of level of CGRP in the lung of rats was observed by immunohistochemical method.Results In the asthmatic group, the number of BALF eosinophils[(2.3±0.9)* 106/L ] was significantly increased than in control group[(0.0)* 106/L]. There was significant difference between two groups (P<0.01). In the asthmatic group, the concentration of CGRP in venous blood[(16.5±3.9)ng/l ] was increased than in control group[(7.3±1.3)ng/l]. There was significant difference between two groups (P<0.01). In the asthmatic group, the concentration of CGRP in BALF[(52.5±14.8)ng/l] was increased than in control group[(36.4±10.0)ng/l]. There was significant difference between two groups (P<0.05). In the lung of asthmatic group, the rate of CGRP positive cell[(28.5±4.2)%] was increased than in control group([8.5±2.7)%]. There was significant difference between two groups (P<0.01). In the lung of asthmatic group, the average grey scale[193.3±14.1] was increased than in control group[100.0±4.8]. There was significant difference between two groups (P<0.01).Conclusion Both CGRP in venous blood and in BALF in asthmatic rats were obviously increased. The expression of CGRP in the lung of asthmatic rats was significant increased. CGRP may play a key role in the pathogenesy of asthma.