| Objective:To observe the preventive effect of Hu-Zhang on radiation-induced lung injury,and to explore its possible mechanism of action,for providing experimental basis for clinical application.Methods:(1)24 clean grade healthy male SD rats were randomly divided into 12Gy irradiation group,16Gy irradiation group,18Gy irradiation group,while,evaluate the animal model with the pathological and lung CT scan.(2)180 clean grade healthy male SD rats,were randomly divided into normal control group,model group,prevention of Hu-Zhang group,Hu-Zhang same day group,Hu-Zhang 28 days group,dexamethasone treatment group,each group had 30 rats.Except the normal control group,other groups were given single irradiation linac in 18Gy.Prevention of Hu-Zhang group began to Gastric lavage with Polygonum cuspidatum extract 1 weeks before irradiation,Hu-Zhang same day group began to Gastric lavage with Polygonum cuspidatum on the first day after modeling.While Hu-Zhang 28 days group began on the 28th days.Dexamethasone treatment group after first day with dexamethasone orally for 4 weeks,4 weeks later 1ml/100g normal saline,normal control group and model group were given saline gavage.4 rats of each group were killed randomly respectively at 1,2,3,4,6,8 weeks.anesthesia with 4%chloral hydrate intraperitoneal injection.Rat heart blood,left lung lavage was determined of concentration of TGF-?,IL-6,ACE by ELISA method.The right lung was taken for HE staining,MASSON staining,changes of rats' pathologic morphology were observed under optical microscope.The change was observed by immunohistochemistry in lung tissue of TGF-?1 protein expression,the expression of RT-PCR method for detection of lung tissue Smad3,Smad4,Smad7mRNA.Result:(1)12Gy,16Gy,18Gy group rats survived,showing alveolar inflammation and in 4 weeks after irradiation,obvious signs of pulmonary fibrosis appeared at 8 weeks,compared to typical 18 Gy,18 Gy of whole lung single irradiation can be made of radiation-induced lung injury model of rats in a relatively short period of time.(2)Pathological observations showed that:Compared with the model group,the extent of its congestion degree,exudation and inflammatory cell infiltration was lighter in prevention of Hu-Zhang group and Hu-Zhang same day group,mainly showed mild alveolitis change.At week fourth,alveolar inflammation score was lower than that in the model group(P<0.05);Pulmonary fibrosis score at eighth weeks was significantly lower than that of model group(P<0.05),and Hu-Zhang 28 days group compared with the model group,no difference;DXM treatment group compared with the model group,the alveolar septum congestion,hemorrhage and inflammatory cell infiltration,fibrosis were significantly lighter(P<0.01).DXM treatment group appeared a small abscess on the third weeks,more abscess in the fourth weeks,and during the application of DXM,the rat weight loss,more deaths,that shows dexamethasone has obvious anti-inflammatory effect,but its immune effects caused by decreased immunity,infection;DXM treatment group compared with Hu-Zhang treatment group,the alveolitis and pulmonary fibrosis to a lesser extent,but no significant difference(P>0.05)(3)TGF-? in rats' plasma and bronchoalveolar lavage fluid increased significantly in fourth weeks and eighth weeks after irradiation.Compared with the normal control group,model group,TGF-?content increased significantly after fourth weeks,P<0.01.Compared with the model group,the content of TGF-? in prevention of Hu-Zhang group,Hu-Zhang same day group,dexamethasone treatment group were lower.At the fourth weeks,eighth weeks that in prevention of Hu-Zhang group,Hu-Zhang same day group was significantly lower than that of model group(P<0.05),DXM treatment group was significantly lower than that in the model group at eighth week(P<0.01).Compared with the model group,Hu-Zhang 28 days group has no difference.Compared with DXM treatment,TGF-?in prevention of Hu-Zhang group,Hu-Zhang same day group was significantly lower than that in DXM group on the first and second weeks.The difference was statistically significant(P<0.05),but no significant difference between the 3,4,6,8 weeks(P>0.05).(4)IL-6 in rats' plasma and bronchoalveolar lavage fluid after irradiation was significantly increased.Model group increased significantly in 4,6,8 weeks,there was significant difference compared with the normal control group(P<0.01).Compared with model and DXM treatment group,IL-6 in prevention of Hu-Zhang group,Hu-Zhang same day group was increased slower.it had significant difference at fourth and eighth weeks(P<0.01).There were significant difference between each time point with DXM treatment group(P<0.01).And Hu-Zhang 28 day group had no difference compared with model group,but at eighth weeks,the IL-6 content was significantly lower than that of DXM group,P<0.01.(5)The contents of plasma ACE and BALF of rats decreased after irradiation,the ACE content of the model group decreased significantly,at each time point were significantly different with the normal control group(P<0.01);ACE content in prevention of Hu-Zhang group,Hu-Zhang same day group decreased,then gradually increase after fourth weeks,but lower than that of DXM group.Compared with the model group and DXM treatment group,that in 4,6,8 weeks were significantly different with statistical significance(P<0.01);Hu-Zhang 28 day group had no difference compared with model group(P>0.05).(6)After irradiation,TGF-??Smad3?Smad4 in lung tissue of rats in each group were with different degrees of expression,the model group was significantly higher than that in normal control group(P<0.01),Hu-Zhang treatment group and DXM treatment group was decreased in different degrees,there are significant differences compared with the model group(P<0.01).The expression of Smad7 of model group were significantly lower than those of normal control group(P<0.01).The expression of Smad7 in in Hu-Zhang treatment group were increased than in the model group,Smad7-mRNA expression in prevention of Hu-Zhang group decreased at first week,increased at second week,there were differences compared with the model group(P<0.05).While,in Hu-Zhang same day group that was increased after the third weeks,there was a significant difference compared with model group(P<0.01).Expression in prevention of Hu-Zhang group and Hu-Zhang same day group was higher than that of DXM group on the 6,8 weeks,there was a significant difference(P<0.01);The expression of Smad7-mRNA in Hu-Zhang 28 group was higher than that in the model group after the sixth weeks,and,but no significant difference compared with DXM treatment group(P>0.05)Conclusion:(1)18Gy whole lung single irradiation can cause the stable,reliable radiation-induced lung injury in rat model,the model can be used for study of radiation-induced lung injury.(2)HRCT can display the dynamic evolution process of radiation-induced lung injury,formed from acute exudative to fibrosis,with the same pathological changes,can be used for the identification of animal model of radiation-induced lung injury.(3)Hu-Zhang can improve the inflammatory exudation of the radiation injury in rat lung tissue,inhibiting fibrosis formation,play some roles in prevention and treatment of radiation-induced lung injury.Hu-Zhang on prevention and control of radioactive lung injury effect may be realized through the following ways:reducing the content of TGF-Pand IL-6,upregulate the expesion of ACE;inhibit express of receptors activated protein Smad3,downregulation of general protein Smad4,promote the expression of inhibitory protein Smad7,therefor inhibit the active of TGF-?/smad signal transduction pathway in rats' radiation-induced lung injury. |
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