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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 effect of Polygoni multiflori on the expression of TGF-β1, Smad3, Smad4 and Smad7 in lung tissue of rats with radiation-induced lung injury and to explore the mechanism of Polygonatum cuspidatum against radiation-induced lung injury. Methods: One hundred and eighty male SD rats were randomly divided into normal control group, Polygonum multiflori prophylaxis group, Polygonum cuspidatum group, Polygonum cuspidatum 28 day group and DXM treatment group. There were 6 rats in each group. Except for the normal control group, The remaining groups were given a linear accelerator chest irradiation a single 18Gy. Polygonum cuspidatum prophylaxis group 1 week before irradiation began to take the administration of Polygonum cuspidatum extract, Polygonum cuspidatum treatment group in the day after the start of the first day to give Polygonum cuspidatum extract intragastric administration, Polygonum cuspidatum 28-day treatment group in the model 28 days Dexamethasone began to daily gastric perfusion with dexamethasone, dexamethasone treatment group started daily dexamethasone on the first day of medication for 4 weeks after 4 weeks to 1 m L / 100 g normal saline, normal control Group and model group to the same volume of saline gavage. Four rats in each group were sacrificed at 1, 2, 3, 4, 6, and 8 weeks respectively, and the right lower lobe tissue was taken. The expression of TGF-β1 protein in lung tissue was observed by immunohistochemical method. Lung tissue Smad3, Smad4, Smad7 mRNA expression. Results: The expression of TGF-β1, Smad3 and Smad4 in the lung tissue of rats in each group were significantly different from those in the normal control group (P <0.01). The expression of TGF- Decreased, compared with the model group there was significant difference (P <0.01). The expression of Smad7 in model group was significantly lower than that in normal control group (P <0.01). The expression of smad7 in Polygonum cuspidatum group was higher than that in model group. The expression of Smad7 mRNA in Polygonum cuspidatum group decreased on the first week and continued to increase after the second week, which was significantly different from the model group (P <0.05) The treatment group on the day after 3 weeks expression increased, compared with the model group there was a significant difference (P <0.01). Compared with the DXM treatment group, the expression levels of Smad7-mRNA in Polygonum uptidee and Polygonum cuspidatum group were significantly higher than those in DXM treatment group at 6 and 8 weeks (P <0.01) But no significant difference compared with DXM treatment group (P> 0.05). Conclusion: Polygonum cuspidatum can reduce the expression of TGF-β1, inhibit the expression of receptor-activating protein Smad3, down-regulate the expression of Smad4 and promote the expression of Smad7, thereby inhibiting the expression of TGF-β / Smad signaling pathway activation, so Polygonum, there is a certain role in the prevention of radiation-induced lung injury.