| Background & ObjectivesAsthma has been one of the severe chronic respiratory diseases. Now, the children and adolescents are the majority of the asthmatic. With the rapid development of economy and change of people'life style in China, the incidence of asthma is growing higher and higher. The traditional asthma therapy-the combination of ICS and LABA plays an important role in controlling asthma and reducing exacerbations. However, this therapy can not meet people's satifaction, which makes it necessary to develop some new asthma therapies. With the development of gene and molecule technologies, it is possible to develop some new drugs addressing some important steps involved in the migration of leukocyte to the airway and pulmonary in asthma. Now, Chemokines and their receptors have emerged as attractive new targets for the therapy of inflammatory disease since they play a crucial role in the inflammation. CCL1 is a kind of chemokines whose receptor is CCR8,and both of them are involved in many inflammatory diseases.CCR8 is preferentially expressed in Th2 cells which migrate through CCL1 gradient, toward the source of CCL1.In addition, Th2 cells play a key role in asthma. However, the acknowledgement of their roles in the asthma is very controversial.In order to observe the expression of CCL1-CCR8 mRNA in the murine lung tissue of bronchial asthma and the response on it from glucocorticoids, and to research the role of CCL1-CCR8 in the pathogenesis of asthma and the anti-inflammatory mechanism of glucocorticoids, a asthma model is made in this paper.Materials & Methods40 health female mice were randomly divided into 4 groups, which were the asthma group, the rCCLl group, the dexamethasone group, and the control group, each group had 10 mice. Mice in the asthma group, the rCCLl group and the dexamethasone group were sensitized with OVA at a concentration of 100ug/mouse in 0.2ml of alum i.h and i.p on Days 1 and 14.and these three groups of mice were challenged daily with 2%OVA-PBS by aerosolizing for 30 min between Days 25 and 31.The rCCL1 group of mice were instilled by using rCCLl at a concentration of 2.5ug/mouse in 25ul of PBS via the nasal meatus in OVA-challenged mice following anesthesia with pentobarbital on Day 31.and the dexamethasone group of mice were injected daily with dexamethasone i.p(2mg/kg)before challenges.The control mice were sensitized and challenged using the physiological saline.All groups of mice were killed on Day 32 and we collected the BALF and lung tissues to determine the total cells in BALF and its classification counts,and measure the level of IL-4 in BALF by ELISA, and observe the expression of CCL1 mRNA and CCR8 mRNA in the lungs by semi-quantitative RT-PCR. Statistical analysis was performed using the SPSS 12.0 statistical program.Results1 Symptoms:The asthma group of mice showed classic asthmatic symptoms.The rCCLl group of mice showed severe asthmatic symptoms and two mice died. Compared with the asthma group, the asthmatic symptoms were relieved in the dexamethasone group and the control mice were normal.2 Pathology:Lung tissues (HE staining) in asthma group showed that a lot of inflammatory cells infiltrated around bronchus and blood vessels and the structure of bronchus was damaged. Compared with asthma group, the rCCL1 group was much worse, on the contrast, the dexamethasone group was much better. The control mice were normal.3 The levels of Inflammatory cells and IL-4 in BALF:The quantity of inflammatory cells in the asthma, rCCL1 and dexamethasone, control group were (9.1±0.9)×106,(9.7±0.8)×106,(4.2±0.5)×106,(1.7±0.4)×106, the percentage of EOS in the asthma, rCCL1 and dexamethasone, control group were (32.4±3.4)%, (39.0±7.1)% and (8.9±0.9)%,(0.6±0.1)%,and the percentage of lymphocyte were (14.0±3.0)%,(17.8±4.2)% and(6.3±0.6)%,(2.9±0.5)%,and the levels of IL-4 were (47.67±11.67)pg/ml,(57.95±9.24)pg/ml and(19.76±4.72)pg/ml,(5.16±1.23) pg/ml.4 The expressions of CCL1mRNA&CCR8mRNA:The expressions of CCL1 mRNA in the asthma, rCCLl and dexamethasone, control group were 0.76±0.16, 1.02±0.31,0.53±0.13,0.11±0.06;The expressions of CCR8 mRNA in the asthma, rCCL1 and dexamethasone, control group were 1.26±0.13,1.43±0.26,0.79±0.12, 0.18±0.09.5 Statistical analysis:Compared with the control group, the level of EOS, lymphocyte and IL-4 in the asthma group were obviously increased;and more obvious in the rCCL1 group;and also increased for the dexamethasone group, even it is much lower than that in the asthma group.Compared with the control group, the levels of CCL1mRNA and CCR8mRNA in the asthma group were obviously increased;and more obvious for the rCCL1 group;and also increased for the dexamethasone group, even it was much lower than that in the asthma group.(all P< 0.05)Conclusions1 The expression of CCL1-CCR8 is up-regulated in the lungs of asthmatic mice. CCL1-CCR8 plays an important role in the formation of asthmatic airway inflammation.2 The airway inflammation of asthmatic mice can be relieved by reducing CCL1-CCR8 expression by glucocorticoids.3 CCL1-CCR8 is probably a promising asthma therapy target.
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