Effects Of ICS On The Expression Of YKL-40in Lung Tissue Of Asthmatic Rats

ObjectiveTo explore the subacute asthma model in rats, after inhaled corticosteroid(ICS)treatment, observing the changes of the airway inflammation, detecting the airway hyperresponsiveness and the expression of Chitinase-3-like-1protein and interleukin-8in thelung tissues.To explore the effect of the ICS on YKL-40、IL-8in the subacute asthmamodel in rats,the possible mechanism of these two cytokines in the pathogenesis ofasthma.Methods1.40male SD rats were randomly assigned to four groups which were clean andhealthy, about a month old, weighing150-170g.the four groups were normal controlgroup, asthma model group, Dexamethasone intervention group, budesonide interventiongroup, each10.2.the experimental rats in Model group, DXM group, BUD group were intraperitonealinjected by10%egg albumin (Ovalbumin, OVA) solution of1ml contains100mg ofaluminum hydroxide on the first day,the8th days. Then were atomized inhalated with2%ovalbumin solution4ml on the15th day,10minutes each time, once a day, lasting for14days. The Control group used0.9%sodium chloride solution instead of ovalbumin inintraperitoneal injection and inhalation.And in half an hour before inhalation, DXM groupwere given intraperitoneal injection of dexamethasone injection, at a dose of0.5mg/kg,BUD group received2ml budesonide inhalation.3. On the28th day of experiment, four groups of rats were anesthetized byintraperitoneal injection of chloral hydrate,then detected the airway hyperresponsiveness.After test the rats were sacrificed with abdominal aorta bleedingmethods,every lung tissue was detected by quantitative real-time PCR,to observerthe expression of YKL-40mRNA and IL-8mRNA in lung tissue, the expression ofYKL-40protein was detected by Western Blot. At the same time the morphology oflung tissue of rats in each group were observed. Results1. Construction of subacute asthma rat model: From the fourteenth day of theexperiment these following symptoms begin to appear:facial scratching, respiratoryfrequency speed, nodding breathing, facial cyanosis, incontinence.on the twenty-eighth daythe airway hyper responsiveness were detected, The results suggest that airway resistancein asthma model group rats increased significantly, compared with the normal controlgroup were statistically significant (P <0.05);HE staining of lung tissue sections suggestthat bronchial and alveolar lung tissue of rats with inflammatory cells increasedsignificantly, eosinophils increased,more viscous secretions, bronchial wall thickening.2.Changes of airway inflammation in lung tissue of BUD group: inflammatory cellssurrounding the alveoli significantly increased in lung tissue of asthma model group,eosinophils increased, there are more viscous secretions, bronchial wall thickening.DXM group and BUD groups the same. Significant inflammatory reaction was notfound in the control group.3.Changes of the airway hyper responsiveness of BUD group: After givinghistamine dihydrochloride atomized inhalation, the airway resistances in Modelgroup compared with Control group increased significantly (P <0.05). Airway resistancein BUD groupcompared with Control group increased (P <0.05), decreased compared withModel group (P <0.05), compared with the DXM group, no significant difference.4.Expression of YKL-40and IL-8mRNA in lung tissue of BUD group: Theexpression of YKL-40and IL-8mRNA in lung tissue of Model group compared withControl group increased significantly (P <0.05). Expression of YKL-40and IL-8mRNAin lung tissue of BUD group compared with Control group increased (P<0.05), decreasedcompared with Model group (P <0.05), compared with the DXM group, no significantdifference.5.Expression of YKL-40protein in lung tissue of BUD group: The expression ofYKL-40protein in lung tissue of Model group compared with Control groupincreased significantly (P<0.05). Expression of YKL-40protein in lung tissue of BUDgroup compared with Control group increased (P <0.05), decreased compared with Modelgroup (P <0.05), compared with the DXM group, no significant difference.Conclusion1. After intraperitoneal injection of ovalbumin solution and atomization inhalation canconstruct the model of subacute asthmatic rats.2. Expression of YKL-40and IL-8mRNA and YKL-40protein in lung tissue of asthmatic rats were increased, suggesting that YKL-40and IL-8are involved inthe pathogenesis of bronchial asthma.3.Aerosol inhalation of Budesonide can relieve airway inflammation, inhibitthe local expression of YKL-40and IL-8mRNA and YKL-40protein in lung tissue.