| Objective: To establish airway remodeling model in asthmatic mice using ovalbumin(OVA),To observe the effects of pioglitazone,a peroxisome proliferator-activated receptor gamma(PPARγ)agonist,on airway remodeling and adiponectin expression in asthmatic mice.To provide a theoretical basis for the PPARγ agonist in treatment of bronchial asthma.Methods: 1.Twenty-four C57 mice were randomly assigned to asthma model group,pioglitazone group and normal control group.The asthma model group and pioglitazone group were sensitized with ovalbumin by intraperitoneal injection.2% OVA was used for intranasal challenge form the 21 st day.The intranasal challenge was performed 3 times a week for 8 weeks.The normal control group was given the same volume of normal saline for sensitization and challenge.The method was the same as above,and the pioglitazone group was given pioglitazone [10mg/(kg.d)]gavage 1 hour before each challenge.Asthmatic group and normal control group were given the same volume of normal saline.2.After the end of the experiment,mice in each group were sacrificed by anesthesia.Blood was taken from the eyeballs to measure blood glucose.3.HE staining was used to observe the pathological changes of lung tissue.4.Masson staining was used to observe the collagen deposition area of airway epithelium.5.Image-Pro Plus image analysis software measures airway morph-ological changes.6.Real-time fluorescence quantitative PCR was used to detect the expression of adipoR1 mRNA,adipoR2 mRNA and PPARγ mRNA.7.Western blot was used to detect the expression of PPARγ and adiponectin(ADPN)protein.Results: 1.Asthma mice showed irritability,shortness of breath,sneezing,incontinence,and no abnormal behavior in normal control mice.2.Blood glucose determination: The blood glucose levels in normal control group,asthma group,and pioglitazone group were 8.27±0.54,8.95±0.74,and 8.22±0.95,There was no significant difference in blood glucose between the three groups(P>0.05).3.Pathological changes of HE staining: Under the microscope,there was no obvious damage to the airway epithelium in normal control mice,and no mucus secretion was seen in the bronchial lumen.In the asthma model group,the airway epithelium was broken and detached,airway epithelium cells were swollen,and there was a large amount of mucus secretion in the bronchial lumen.In the pioglitazone group,airway epithelial cells were seen to be broken and detached,and mucus retention was observed in the bronchial cavity,which was less than that in the asthma model group.4.Masson staining changes in each group: There was a small amount of collagen deposition under the airway epithelium in the normal control group.The collagen deposition in the airway epithelial cells was evident in the asthma model group.The collagen deposition area was the largest in the asthma model group.The collagen deposition in the pioglitazone group was observed under the airway epithelium,and the deposition area was more asthmatic.The group was decreased.Image-Pro Plus image analysis software showed that the proportion of airway subepithelial collagen deposition in each group was(8.75±1.25)%,(44.71±6.88)%,and(23.48±2.42)%,respectively.The difference was statistically significant(P<0.05).5.Airway morphological changes: Airway wall thickness in the normal control group,asthma model group,and pioglitazone group was(15.39±0.83)μm,(32.18±0.76)μm,(23.84±0.91)μm,and there were statistical differences(P<0.01).The smooth muscle thickness in the above three groups was(3.42±0.27)μm,(11.46±1.86)μm,and(7.70±0.16)μm respectively,and the difference was statistically significant(P<0.01).6.Quantitative Real-time PCR detection: The expression levels of PPARγ mRNA in the normal control group,asthma model group,and pioglitazone group were(0.96±0.0260),(2.12±0.1473),and(4.28±0.1640),re-spectively.The difference was statistically significant(P<0.05).The expression of AdipoR1 mRNA in the three groups was(0.99±0.1250),(0.44±0.0733),and(1.88±0.0510),respectively.The difference was statistically significant(P<0.05).The expression of AdipoR2 mRNA in the three groups was(1.00±0.1170)and(0.46±0.0733),(3.13±0.1300),respectively.The difference was statistically significant(P<0.05).7.Wetern-blot assay: adiponectin was weakly expressed in the asthma group,slightly increased in the normal control group,significantly increased expression in the drug group.The optical density in three groups were(0.12±0.01),(0.25±0.01),and(0.49±0.03),respectively.There was a statistically significant difference(P<0.05).PPARγ protein expression was seen weakly expressed in the normal group,slight increase in the asthma group,strong expression in the drug group.The optical density in three groups were 0.11±0.01,0.31±0.01,0.51±0.01,the difference being statistically significant(P <0.05).Conclusion:1.Pioglitazone can inhibit airway remodeling and inflammation in asthmatic mice.2.Pioglitazone can upregulate the expression of PPARγ and adiponectin in lung tissue of mice.3.Pioglitazone may up-regulate the expression of adiponectin through activation of PPARγ pathway,thereby inhibiting airway remodeling and airway inflammation in bronchial asthma. |
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