PDTC对百草枯致肺纤维化大鼠TGF/β1及CTGF表达的影响

摘要

Objective To investigate the expression of TGF - β1 and CTGF in acute paraquat poisoned rats and the effect of Pyrrolidine dithiocarbamate ( PDTC ) . Methods 144 Sprague - Dawley ( SD) rats were randomly divided into four experimental groups: Control group, PDTC group, PQ group and PQ + PDTC group. On the 1st, the 3rd, the 7th, the 14th, the 28th and the 56th day after treatment, the level of TGF - pi in serum was measured by ELISA and the protein expression of CTGF was assayed by western blot. The content of hydroxyproline (Hyp) in lung tissues was detected. Meanwhile, the lung pathological changes of rats were observed. Results The level of TGF - pi in PQ group was significantly increased at all time points compared with control and PDTC group ( P < 0. 05 or P < 0. 01 ) . With the time passing, the expression of CTGF in PQ group increased gradually compared with control group (P><0.05 or P <0. 01 ) . The increasing speed of CTGF was gentle on the 3 rd and the 7 th day. While it's increasing speed was rapid from the 14 th to the 56 th day. Hyp contents of the lung tissue in PQ group was significantly higher than control and PDTC group on the 14 th, the 28 th and the 56 th day (P <0. 01 ) . Correlation analysis showed TGF - pi and CTGF were positively correlated with hydroxyproline ( P < 0. 05 or P < 0. 01) . PDTC treatment led to a significant decrease of TGF - β1 , CTGF and Hyp compared with PQ group in corresponding time points (P < 0. 05 or P < 0. 01 ) . Noteworthy, in PQ + PDTC group, the occurrence of pathological changes were drastically attenuated. Conclusion Overexpression of TGF - pi and CTGF could play important role in lung injury of poisoned rats. PDTC , as a strong NF - kB inhibitor , may inhibit NF - kB activity and futher significantly decreased expressions of TGF - pi and CTGF, leading to drastically attenuated pulmonary inflammation and fibrosis. However, the mechanisms of PDTC intervention still remain to be explored.%目的 观察急性百草枯(PQ)中毒大鼠转化生长因子β1(TGF-β1)及结缔组织生长因子(CTGF)表达水平的变化,探讨四氢吡咯二硫代氨基甲酸酯(PDTC)的治疗机制.方法 SD大鼠144只随机分为对照组6只、PDTC对照组36只、PQ染毒组56只、PDTC干预组46只.染毒组和干预组给予生理盐水稀释PQ80mg·kg-1一次性灌胃后2h,干预组给予PDTC100mg·kg-1一次性腹腔注射,染毒组给予等量生理盐水腹腔注射;对照组和PDTC对照组于生理盐水1mg·kg-1灌胃后2h,PDTC对照组给予PDTC100mg·kg-1一次性腹腔注射,对照组给予等量生理盐水腹腔注射.于不同处理后1、3、7、14、25、56d观察大鼠中毒表现及肺组织病理改变;测定肺组织羟脯氨酸(Hyp)含量;ELISA测定血清TGF-β1水平;Western blot测定肺组织CTGF蛋白表达;分析TGF-β1、CTGF与Hyp含量的相关性.结果 大鼠染毒后与对照组比较,血清TGF-β1含量各时段均明显升高,差异有统计学意义(P＜0.05或P＜0.01);肺组织CTGF蛋白表达随时间延长而逐渐升高,各时段明显高于对照组(P＜0.05或P＜0.01);肺组织Hyp含量14、28、56d明显升高(P＜0.01).经PDTC治疗后,各时段TGF-β1、CTGF蛋白水平明显降低,差异有统计学意义(P＜0.05或P＜0.01);Hyp含量在28、56d明显降低(P＜0.01);TGF-β1、CTGF与Hyp含量均为正相关(P＜0.05或P＜0.01);病理检查PDTC干预组肺组织炎症及纤维化程度均较轻.结论 TGF-β1、CTGF表达增强是参与PQ致肺损伤的重要机制;PDTC可能通过抑制NF-κB活化,降低TGF-β1水平及其下游因子CTGF的蛋白表达,减轻PQ中毒大鼠的肺损伤.