| Objective:Through observing the serum concentration of IL-4,TGF-β1and the expression of Rho kinase in asthmatic model,to investigate:1.the effect of simvastatin on airway inflammation and remodeling in asthma,thus provide a new way for clinical prevention and treatment of asthma.2.the possible mechanism of simvastatin intervention on airway inflammation and remodeling.Method:Fifty adult male guinea pigs (six weeks old, weights from250to300grams) were randomly divided into five groups:control group, asthmatic model group, S1group (simvastatin20mg/kg treat group),S2group (simvastatin40mg/kg treat group) and S3group(simvastatin60mg/kg treat group). Guinea pigs were sensitized and repeatedly challenged with OVA to duplicate asthmatic models.The asthmatic model group and simvastatin intervention groups were sensitized and challenged with OVA while the control group used normal saline instead of OVA, the others was same with the asthma group.Besides be sensitized and challenged,animals of simvastatin groups were respectively injected intrapertoneally with20mg/kg,40mg/kg,60mg/kg simvastatin suspension30min before every challenge. After24hours of the last challeng, guinea pigs were sacrificed by exsanguinating rapidly from femonal artery.Then we collected the serum,bronchoalveoiar lavage fluids(BALF) and lung tissue of each group. The total cells and eosinophils counts in BALF were counted.The lung tissue sections were stained with hematoxylin-eosin (HE) staining method. The level of IL-4and TGF-β1in serum were assayed by ELISA.The expression of Rock2were measured by immunohistochemical method combined with microimage analysis.Results:1.The asthmatic model of guinea pigs were successfully established.2.The number of total cells and EOS (×104/ml)in BALF:The total cells and EOS in BALF of the asthma group(401.8±110.7,61.9±12.5),Sl(273.6±33.1,27.8±9.1), S2(207.9±35.8,18.4±7.3),S3(199.3±28.6,28.6±10.7) were significantly increased compared with the control group (P<0.01,P<0.01).The total cells and EOS in BALF of the simvastatin intervention groups were lower than these of the asthma group (P<0.05)while the number was higher than the control group (P<0.05).3.Lung tissue pathological changes:the lung tissue of control group was normal integrity and no stenosis of lumen, epithelial cells no obvious hyperplasia, no airway mucosal edema,no inflammatory cells and a complete normal alveolar septa. In the lung tissue of asthma model group,we find that lots of inflammatory cells infiltrating, bronchial smooth muscle hypertrophy,tube wall thickening,luminal stenosis and alveolar septum inhomogeneous thickened. After the treatment with simvastatin,the change of the above mentioned pathology character were decreased.4.The serum level of IL-4, TGF-β1were measured by ELISA:Compared with the control group(18.52±3.70,22.79±6.56),the level of IL-4, TGF-β1were significantly increased in the asthma model group(38.23±6.33,47.61±8.08),S1group(28.62±5.58,38.96±6.38),S2group (23.69±4.08,30.46±8.61),S3group(30.49±6.86,40.10±7.05)(P<0.01). Asthma group was the highest among the five groups.S2group was higher than S1,S3group, The difference was statistically significant(P<0.05).5.Result of immunohistochemistry: the expression of Rock2in lung tissues was statistics for the average light density values.The asthma group(0.153±0.014), S1(0.121±0.017), S2(0.097±0.021)and S3(0.125±0.032)were significantly higher than control group(0.078±0.011)(P<0.05). And these were lower in simvastatin groups than asthma group (P<0.05).S2group was lower than S1group and S2group.6.Result of correlation analysis:the average light density values of Rock2protein was positively correlated with the level of IL-4and TGF-β1in asthmatic animals(r=0.533,P<0.05.r=0.622,P<0.01).It was a significant positively correlation between IL-4and TGF-β1(r=0.625,P<0.05).Conclusion:1. We can succesfully established the asthmatic model of guinea pigs by sensitized with antigen and aluminum hydroxide, and challenged with repeated exposureto aerosolized ovalbumin,which are charactered by airway inflammation and airway remodeling.2.Simvastatin can reduce airway inflammation,regulating Thl/Th2imbalance by reducing the IL-4. Simvastatin can inhibit asthma airway remodeling by suppressing the level of TGF-β1.3.The expression of Rock2protein in lung tissues of asthma group was significantly increased compared with the control group,which suggested that the Rho/Rock signaling cascade plays a pivotal role in the develepment of asthma.The expression of Rock protein of simvastatin groups were obviously decreased compared with the asthma group and those were increased compared with the control group,the result implicated that simvastatin may have potential therapeutic role in asthma through inhibition of Rho/Rock signaling pathway. |
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