Level of Serum Melatonin and Cycloxooygenase-2 and Its Relativity in Asthmatic Children.

Objective To discuss the interaction and clinical significance of the level of serum melatonin (MT) and cyclooxygenase(COX)-2 in children with asthma. Methods Fifty-nine asthmatic children with acute attack (asthma group, 39 boys and 20 girls, aged 1~6 years old) and 28 sex- and age-matched healthy children (control group) from Second People' Hospital of Changzhou, Affiliated to Nanjing Medical University and Third People's Hospital of Nantong from March 2007 to March 2008 were enrolled in the study. The asthmatic attack diagnosis was based on the Convention of Bronchial Asthma for Child Prevention and Cure. Asthma group children were sub-divided into 2 groups according to the use of adrenal cortex hormone for 2 weeks before serum sample collection, sub-group A(n=39, without the application of glucocorticoid) and sub-group B(n=20, treated with glucocorticoid). There had no significant difference of age and gender between asthma group and control group (P>0.05). The serum samples were withdrawn for melatonin and cyclooxygenase-2 measurement. The above tests were performed by using the enzyme-linked immunosorbent assay. Informed consent was obtained from all children' guardians, and the trial approved by the ethics committee of Second People' Hospital of Changzhou. Results Serum melatonin level was significantly lower and cyclooxygenase-2 level was significantly higher in asthma group than those of control group [melatonin: (2.44±0.83) pg/mL vs. (4.48±1.11) pg/mL, P 0.05)between sub-group A and sub-group B, while cyclooxygenase-2 level was significantly higher in sub-group A compared with sub-group B(P<0.05). A significant negative correlation was found between serum melatonin and cyclooxygenase-2 levels in asthma group (r=-0.453, P<0.001). The serum level of cyclooxygenase-2 decreased with the using of glucocorticoid(P<0.05). Conclusion Melatonin and cyclooxygenase-2 maybe involve in the pathogenesis of asthma, especially the high expression of cyclooxygenase-2 may be one of the reasons that cause respiratory inflammation and airway hyper responsiveness in children with asthma. Key words: melatonin(MT); cyclooxygenase-2(COX-2); asthma; relativity