Effects of dexamethasone on interleukin-4,interleukin-5 and airway hyperresponsiveness of asthmatic model in guinea pig

Abstract

Objective To explore the effects of dexamethasone on interleukin-4 (IL-4) ,IL-5 in serum and airway hyperresponsiveness(AHR) of asthmatic model in guinea pig and to provide theoretical basis for the treatment of bronchial asthma(asthma). Methods This experiment included three groups:normal control group,asthmatic model group and dexamethasone treatment group,involving 10 guinea pigs in each group.Asthmatic models in guinea pigs were constructed by immunization of intraperitoneal injection with saline ovalbumin(OVA) and challenge of inspiration with nebulized OVA. A three-way cannula was inserted into the lumen of the trachea for mechanical ventilation and the intratracheal pressure (IP) was measured simultaneously for reflecting airway responsiveness. The levels of IL-4, IL-5 in serum of guinea pigs were determined using enzyme-linked immunosorbent assay (ELISA). Results The levels of IL-4, IL-5 of asthmatic model group (38.2±3.4) ng/L and (344.4±21.8) ng/L were significantly higher than those of normal control group (19.8±1.2) ng/L and (77.8±26.0) ng/L( P＜0.01). The levels of IL-4,IL-5 of dexamethasone group (22. 0±1. 8) ng/L and (234.6±35.1) ng/L were significantly lower than those of asthmatic model group( P＜0.01). The airway responsiveness of asthmatic model group (0. 013±0.014) g/L was significantly higher than that of normal control group (0. 168±0. 186) g/L (P＜0.01). Compared with that of asthmatic model group, the airway responsiveness of dexamethasone group (0. 144±0. 154) g/L decreased significantly( P ＜ 0.01), but they did not have any statistical significance from that of normal control group( P ＞ 0.05). Conclusions Dexamethasone could efficiently decrease the AHR of asthmatic guinea pig. The mechanism may be that dexamethasone could prevent the production of IL-4, IL-5 in asthmatic guinea pig. Key words: Dexamethasone; Asthma; Interleukin-4 ; Airway hyperreactivity