Effect Of Etanercept On Airway Inflammation Of Asthmatic Rats

Objective:Tumor necrosis factor-α(TNF-α) play a important role in airway inflammation of asthma. This study aimed at observing the effects of Etanercept on airway inflammation of asthmatic rats and exploring its mechanism.Methods: 30 Sprague-Dawley(SD) male rats were randomly divided into three experimental groups(10 in each) : (1) Asthmatic group: Rats were immunized on day 1, day 8 and day 15 by int raperitoneal injection of 100 mg ovalbumin (OVA) in 1 ml of saline with 100 mg of aluminum hydroxide. From day 16 the animals were challenged with aerosolized OVA (1 % in saline) for 20 minutes per day for 3 consecutive days. (2) Etanercept Group: OVA sensitized rats were injected 0.5mg/kg Etanercept every 2 days. (3) Control group: OVA and Etanercept was replaced with normal saline (NS). In the 24 hours after the last challenge, rats were killed to collect lung tissue and airway lavage fluid (BALF). BALF cells and supernatant is separated by centrifugal separation. lung tissue is made into lung biopsy specimens through dehydration, paraffin embedding.Tumor necrosis factor-α(TNF-α) of BALF supernatants were measured by Elisa method. Total and differentiated leukocytes counts in bronchoalveolar lavage fluid (BALF).IL-4 levels of lung specimens were assessed with the use of immunohistochemical. data for each group were statistically analyzed and compared.Results:TNF-αlevels of BALF supernatants in Etanercept Group (196±13) is decreased compared with asthma Group (236±8) (p<0.01),The number of eosinophils and neutrophils of BALF in Etanercept Group reduced compared with asthma Group (p <0.01);There was a significant decrease in IL-4 levels of lung tissues in Etanercept Group comparing with asthmatic group( P < 0. 05 respectively);But these index in Etanercept Group significantly higher than control group.Conclusion:The inhibitory effect of Etanercept probably play a role in decreasing airway inflammation of asthmatic rats model.