PURPOSE: To evaluate the effect of erythromycin on the late phase reaction, bronchial hyperresponsiveness (BHR), and T-cell related cytokine m-RNA expression in brown Norway rats (BNR) induced by ovalbumin (OA) sensitization.
METHODS: Thirty BNR were equally divided into three groups. Each group I and II BNR were sensitized by OA. Fifteen days later, a provocation test by OA was performed. Erythromycin (20 mg/kg/day) was given orally for 14 days beginning on the first day of OA sensitization for group I animals, and only normal saline was given orally for 14 days beginning on the first day of OA sensitization for the group II animals. Control animals in group III breathed aerosolized saline rather than OA under the same conditions as group II animals. After OA provocation, the animals were anesthetized. Pulmonary function tests (PFT) were performed at baseline and after varying doses of acetylcholine. Thereafter, bronchoalveolar lavage (BAL) was performed and the lungs were examined histologically. Total RNA was extracted from lung tissue and reverse-transcriptase polymerase chain reaction (RTPCR) was performed using primers for IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, IFN-γ, iNOS and β-actin.
RESULTS: Group I OA and erythromycin treated BNR and Group II OA treated BNR had similarly worse PFT results, similarly more severe bronchoconstriction in response to acetylcholine, and similarly more severe inflammation in lung tissue than group III control BNR. Group I and group II had similarly higher IL-2, IL-4, IL-10 and IFN-γ cytokine levels in BAL fluid and similarly higher IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, IFN-γ, TNF-α and iNOS m-RNA levels when compared to group III control BNR.
CONCLUSION: In conclusion, erythromycin was not effective both in preventing late phase bronchoconstriction and BHR and the inflammatory response, and did not decrease IL-2, IL-4, IL-5, IL-6, IL-10, IL-12 and IFN-γ and iNOS m-RNA expression.
CLINICAL IMPLICATIONS: Erythromycin was not effective both in preventing late phase bronchoconstriction and BHR.
DISCLOSURE: Ching-Chi Lin, None.