虎杖对放射性肺损伤大鼠TGF-β1/Smad蛋白的影响

The Influence of Huzhang on the TGF-β1/Smad Proteins of Radioactive Lung Injury Rat

目的:观察虎杖对放射性肺损伤大鼠肺组织TGF-β1蛋白、Smad3,Smad4,Smad7mRNA表达的影响,探讨虎杖防治放射性肺损伤的作用机理。方法:随机将180只清洁级雄性SD大鼠分为正常对照组、虎杖预防组、虎杖当天组、虎杖28天组、DXM治疗组,共6组,每组30只,除正常对照组外,其余各组均给予直线加速器全胸单次照射18Gy。虎杖预防组于照射前1周开始灌服虎杖流浸膏,虎杖当天治疗组于造模后第1天开始每日予虎杖流浸膏灌胃,虎杖28天治疗组于造模后第28天开始每日予虎杖流浸膏灌胃,地塞米松治疗组造模后第1天开始每日予地塞米松灌胃用药4周,4周后予1 m L/100 g生理盐水灌胃,正常对照组和模型组予等容积的生理盐水灌胃。每组分别于1、2、3、4、6、8周随机处死4只大鼠,取右肺下叶组织,免疫组化法观察肺组织TGF-β1蛋白表达的变化,RT-PCR法检测肺组织Smad3、Smad4、Smad7mRNA的表达。结果:各组照射后大鼠肺组织均有TGF-β1、Smad3、Smad4不同程度的表达,模型组显著高于正常对照组(P<0.01),各虎杖治疗组与DXM治疗组表达有不同程度下降,与模型组比较有显著差异(P<0.01)。而模型组Smad7的表达显著低于正常对照组(P<0.01)。各虎杖治疗组smad7表达较模型组均有升高,其中虎杖预防组Smad7-mRNA表达在第1周时下降,第2周后表达持续增加,与模型组比较有差异(P<0.05),虎杖当天治疗组在第3周后表达增加,与模型组比较有显著差异(P<0.01)。虎杖预防组与虎杖当天治疗组在第6、8周时表达高于DXM治疗组,有显著差异(P<0.01);虎杖28天治疗组在第6周后Smad7-mRNA表达高于模型组,但与DXM治疗组比较无显著性差异(P>0.05)。结论:虎杖能够降低TGF-β1蛋白的表达,抑制受体激活性蛋白Smad3的表达,下调通用性蛋白Smad4的表达,促进抑制性蛋白Smad7的表达,从而抑制放射性肺损伤大鼠肺脏中TGF-β/Smad信号传导通路的激活,因此虎杖有一定的预防放射性肺损伤的作用。

Objective： To observe the influence of Huzhang on TGF- β / Smad proteins of radiactive lung injury rat and to explore its possible mechanism of preventive effect. Methods：（ 1） 180 clean grade healthy male SD rats were randomly divided into normal control group,model group,prevention of Huzhang group,Huzhang same day group,Huzhang 28 days group,dexamethasone treatment group,each group had 30 rats. Except the normal control group,other groups were given single irradiation linac in 18 Gy. Prevention of Huzhang group began to gastric lavage with Polygonum cuspidatum extract 1week before irradiation. huzhang same day group began to gastric lavage with Polygonum cuspidatum on the first day after modeling. While Huzhang 28 days group began on the 28 th day. Dexamethasone treatment group after first day with dexamethasone orally for 4 weeks,4 weeks later 1 m L /100 g 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. The right lung was taken for observing TGF- β1 protein expression by immunohistochemistry and wedetected the expression of Smad3,Smad4,Smad7 mRNA by RT- PCR method. Result： After irradiation,TGF- β1,Smad3,Smad4 in lung tissue of rats in each group were with different degrees of expression,that in the model group was significantly higher than that in normal control group（ P〈0. 01）. That in Huzhang treatment group and DXM treatment group was decreased in different degrees,there were significant differences compared with the model group（ P〈0. 01）. The expressions of Smad7 of model group were significantly lower than those of normal control group（ P〈0. 01）. The expression of Smad7 in in Huzhang treatment group were increased than that in the model group. Smad7- mRNA expression in prevention of Huzhang group decreased at first week,increased at second week,there were differences compared with the model group（ P〈0. 05）. While in Huzhang 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 Huzhang group and Huzhang 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 Huzhang 28 group was higher than that in the model group after the sixth weeks,but there was no significant difference compared with DXM treatment group（ P〉0. 05）. Conclusion： Huzhang can reduce the content of TGF- β1,inhibit express of receptors activated protein Smad3,downregulat the general protein Smad4 and promote the expression of inhibitory protein Smad7,therefore inhibit the active of TGF- β / smad signal transduction pathway in rats＇ radiation- induced lung injury. So Huzhang has certain prevention of radioactive lung injury.