| Objective:To investigate the effects of Pingchuan Particles on lung histopathology of asthmatic rats, and the influences of Pingchuan Particles on the protein and mRNA content of VEGF, Notchl and DLL4 in the lung tissues of asthmatic rats, and the change of related factors after Notch signal blocked by DAPT, in order to elucidate the mechanism of Pingchuan Particles on airway remodeling in chronic asthma.Methods:In the experiment one, two and three, randomly divide 60 Wistar rats into four groups:normal control group, model group, dexamethasone group and Pingchuan Particles group, each with 15 rats. On Day 0 and Day 8, rats in the asthmatic group were sensitized by intraperitoneal injection with lml ovalbumin/aluminum hydroxide mixture (including lmg ovalbumin and 100mg aluminum hydroxide mixture); on Day 9, the rats were challenged with 5% ovalbumin for five days,30 min per day; on Day 14, challenge with every other day, for eight weeks. The normal control group were sensitized and challenged with normal saline. Rats in each group were all conducted with intervention on Day 4 after the second sensitization. Rats in Pingchuan Particles group were given Solution of Pingchuan Particles with 3.6g/Kg. Rats in the dexamethasone group received intraperitoneal injection with lmg/Kg, during sensitization stage, the rats received intraperitoneal injection lh before per challenge; normal control group and model group were all given gavage with normal saline lml/100g. 24 hours after the last challenge, lung tissue were taken to observe their morphological change through the light microscope and electron microscope; IHC (Immunohistochemistry) was adopted to determine VEGF, Notchl and DLL4 protein expression in the lung tissue; Real Time PCR were used to determine VEGF, Notchl and DLL 4 mRNA expression.In the experiment four,32 Wistar rats were randomly divided into normal control group, model group, DAPT group, and Pingchuan Particles group. The method of modeling is the same as above. Four days after the second sensitization, normal control group and model group were given daily normal saline 1ml/100g gavage; DAPT group were given DAPT 500μg/100g by intraperitoneal injection; Pingchuan Particles group were given Pingchuan Particles 3.6g/Kg orally. Western blot was adopted to determine VEGF, Notchl and Hes-1 protein expression.Results:1.The lung tissue slicesunder light microscope are found normal after observation. Rats in the control group do not show obvious airway remodeling pathological changes; compared with rats in the normal control group, rats in the bronchial asthma group show clear airway remodeling pathological manifestations including inflammatory cell infiltration, disordered arrangement of bronchial epithelial cells, epithelium necrosis and shedding, mucosal edema, smooth muscle hyperplasia, angiogenesis, increased vascular wall thickness, the alveolar collapse, thickening of alveolar interval etc. through HE staining in their lung tissue. Remodeling pathological changes showed significant reduction for rats in the dexamethasone group and the Pingchuan Particles group. Pingchuan Particles group showed even more clear reduction.2.Lung tissue slices under electron microscopy in the model group shows partial dissolution of epithelial cells, ciliated columned epithelium degeneration, cellular atrophy, greater cell gaps, mitochondrial swelling and mitochondrion, basilar membrane discontinuity, collagen fibers significant increase, the cilia falling short with reduced microvilli. The dexamethasone group and the Pingchuan Particles group both show reduction, the control group does not show any obvious pathological changes.3.The results of immunohistochemistry showed that:the expression of VEGF, Notchl and DLL4 in the Pingchuan Particles group and dexamethasone group were both lower than the model group (P<0.05), thus higher than the normal control group (P<0.05), the Pingchuan Particles group were lower than dexamethasone group (P<0.05)4.The results of Real Time PCR showed that:the expression of VEGF, Notchl and DLL4 mRNA in the model group were lower than both Pingchuan Particles group and dexamethasone group (P<0.05); the Pingchuan Particles group were lower than dexamethasone group (P< 0.05), and higher than the normal control group (P<0.05)5.Western blot results showed that the model group rat lung tissue VEGF Notchl Hes-1 protein expression, compared with the normal control group was significantly higher (P<0.05); DAPT group and asthma group of particles VEGF, Hes-1 protein expression is higher than normal control group, compared with the model group (P<0.05); Notchl expression DAPT group and model group no significant difference (P> 0.05), asthma particle group than the model group (P<0.05).Conclusions:1.Pingchuan Particles can reduce the infiltration of inflammation cells of the lung tissue, relieve bronchial mucosa and airway wall thickening, reduce vascular wall thickness, and reduce vascular proliferation.2.Pingchuan Particles can reduce the swelling of mitochondria in epithelial cells, decrease collagen deposition, inhibit the cilia and microvilli decreasing.3.Pingchuan Particles can decreased the expression of VEGF, Notchl and DLL4 protein in the lung tissue of asthmatic rats.4.Pingchuan Particles can decreased the expression of VEGF, Notchl and DLL4 mRNA in the lung tissue of asthmatic rats.5. Pingchuan particles can by blocking Notch signaling to inhibit the expression of VEGF and thus affect vascular remodeling of asthma. |
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