Effects Of Leukotrienes Receptor Antagonist On Airway Extracellular Matrix Remodeling In Rats With Asthma

Objective: To study the relationship between transforming growth factor-β1(TGF-β1), matrix metalloproteinase-9(MMP-9) , tissue inhibitor of metalloproteinases-1(TIMP-1) and airway extracellular matrix deposition ; And to investigate the effects of Leukotrienes Receptor Antagonist -Montelukast(MK) on airway extracellular Matrix remodeling in rats asthmatic model.Method: Twenty-four Cleaning male SD rats ,weights from 180 to 200 grams,were randomly divided into three groups(8 in each group): control group, asthmatic group and MK group. The asthmatic group and MK group rats were sensitized on the first day and the 8th day with ovalbumin(OVA) (100mg) combinated with Bacillus Calmette-Guerin Vaccine(50 hundred million bacterial vaccines) and AL(OH)3(100mg) by intraperitoneal injection. And then those rats were challenged repeatedly with inhaled aerosolized OVA in a 20cm×30cm×40cm not close tightly box from fifteen day. The OVA concentration was increased every 4 times from 1% to 1.5%, 2%,2.5%,3%, rats were challenged 30minutes each time,every other day ,20times together. The MK group was treated with MK (15mg/Kg) every day besides be sensitized and challenged. The control group rats were sensitized and challenged with normal saline. After last challenge of 24 hours, rats were anesthesiaed by 1% Pentobarbitalin and measured Pulmonary function(the airway basic expiratory resistance and airway expiratory resistance after injected Ach) . Lung tissues were sliced and stained with H.E. The parameters such as bronchial basement membrane perimeter(Pbm),total bronchial wall area(WAt),and smooth muscle area(WAm) , which reflect the thickness of airway wall, were measured by image analysis system. The Masson staining was used to observe collagen deposition on airway. The level of LTD4 in serum was measured by ELISA. The expression of TGF-β1,MMP-9 and TIMP-1 in airway tissues were observed by immunohistochemistry combined with the micro-image analysis,and mean optical density of TGF-β1,MMP-9 and TIMP-1 were measured by image analysis software.Results1 The effect of MK on the airway remodeling in asthmatic rats: Obvious infiltration of inflammatory cells and proliferation of goblet cells as well as enhancement of mucus and smooth muscle hyperplasia can be seen in the lung tissue of asthmatic rats.After the treatment with MK,the decrease of the above mentioned effects were observed .Observe the airway wall area and smooth muscle area in these three groups by optical microscope and image analysis system:The airway wall area and smooth muscle area were significantly thicker in asthmatic group (94.09±5.62,33.51±4.12)and MK group (85.78±3.70,26.30±7.09)than those in control group (70.18±7.09,16.86±2.93) (P<0.01).The airway wall area,smooth muscle area were significantly thinner in MK group than those in asthmatic group (P<0.05).2 The effect of MK on pulmonary function of asthmatic rats:The airway basic expiratory resistance was higher in asthmatic (1.9804±0.3885)and MK groups(1.5402±0.3524) than that in control group (1.1046±0.2085) (P<0.01),and that was lower in MK group than in asthmatic group(P<0.05).The change of expiratory resistance was higher in asthmatic group and MK group than that in control group after Ach challenge,and that was lower in MK group than in asthmatic group.3 The effect of MK on the collagen deposition in asthmatic rats:The expression of Collagen in airway tissue of asthmatic group (0.0477±0.0041)and MK group(0.0289±0.0026) was significantly higher than that of control group(0.0197±0.0030)(P<0.01) . And that was lower in MK group than in asthmatic group(P<0.01).4 The effect of MK on the level of LTD4 in serum of asthmatic rats: The concentration of LTD4 in serum of asthmatic group(10.7±3.5) and MK group(9.8±1.6) was significantly higher than that of control group(6.1±0.7)(all P<0.01), while the concentration of LTD4 between asthmatic group and MK group were not statistical significance(P>0.05).5 The expression of TGF-β1,MMP-9 and TIMP-1 in airway tissues were observed by immunohistochemistry combined with the micro-image analysis,the average optical density were used as statistic:TGF-β1 :the expression of TGF-β1 in asthmatic group (0.3615±0.049) and MK group(0.3109±0.036) were higher than that in control group(0.2325±0.060) (P<0.01),and that was lower in MK group than in asthmatic group (P<0.05).The line related analysis results: The expression of collagen and TGF-β1 were positive correlation (r=0.8392,P<0.05).MMP-9 :the expression of MMP-9 in asthmatic group (0.3710±0.0475) and MK group(0.3129±0.0368) were higher than that in control group(0.2228±0.0439) (P<0.01),and that was lower in MK group than in asthmatic group (P<0.05).TIMP-1 :the expression of TIMP-1 in asthmatic group (0.4680±0.057)and MK group(0.3604±0.047) were higher than that in control group(0.2359±0.050)(P<0.01),and that was lower in MK group than in asthmatic group (P<0.01).MMP-9/TIMP-1:the ratio of MMP-9/TIMP-1 in asthmatic group(0.79±0.04) was lower than that in control group(0.95±0.12)(P<0.01). The line related analysis result: The expression of collage and MMP-9/TIMP-1 were negative correlation (r=-0.8963,P<0.05).Conclusion1 The expression of TGF-β1,MMP-9 and TIMP-1 in asthmatic group were significantly increased compared with the control group,and the ratio of MMP-9/TIMP-1 in asthmatic group was significantly decreased compared with control group.2 The combination measure of TGF-β1,MMP-9 and TIMP-1 have some reference value to diagnose airway remodeling of asthma.3 Montelukast were significantly decreased the expression of TGF-β1,MMP-9 and TIMP-1 in airway tissues of asthmatic rats , and turns the ratio of MMP-9/TIMP-1 to normal.4 Montelukast may affect the level of TGF-β1,MMP-9 and TIMP-1,and adjust the MMP-9/TIMP-1 balance, and reduce airway Extracellular Matrix deposition,change asthma progression.