Objective To observe the effects of curcumin on pulmonary fibrosis and functions on paraquat (PQ)-challenged rats, and investigate the possible mechanism. Methods 108 SPF Wistar rats were divided into three groups according to random number sheet: normal saline (NS) control group, PQ model group and curcumin-treatment group. The rats in each group were subdivided into three subgroups according to different time points (3, 7, 14 days), with 12 rats in each subgroup. PQ-challenged models were reproduced by intragastrical administration of PQ solution 50 mg/kg, and those in NS control group were given the equal volume of NS. After 30 minutes, the rats in curcumin-treatment group were given 200 mg/kg of curcumin by intraperitoneal injection, and those in NS control group and PQ model group were given the equal volume of NS. At 3, 7, 14 days, the tidal volume (VT) was examined, and the blood was drawn from femoral artery for blood gas analysis. Then the rats were sacrificed and the lung tissues were harvested, the hydroxyproline (Hyp) content was measured by alkaline hydrolysis; the expression of transforming growth factor-β1 (TGF-β1) was determined by immuno-histochemistry; the distribution and the change of the pulmonary collagen fiber were observed after Masson staining. Results After exposure to PQ, the VT and arterial partial pressure of oxygen (PaO2) were decreased gradually, and the levels of Hyp and TGF-β1 were increased gradually, reaching the trough or the peak at 14 days, which were significantly lower or higher than those in NS control group [14-day VT (mL):1.52±0.33 vs. 2.81±0.47, 14-day PaO2(kPa): 5.87±0.95 vs. 14.15±1.02, 14-day Hyp (μg/mg): 3.12±0.06 vs. 1.14±0.05, 14-day TGF-β1 (integral A value): 29.72±4.27 vs. 4.15±0.52, all P < 0.01]. After intervene of curcumin, the parameters were significantly improved as compared with those of PQ model group [14-day VT (mL): 2.34±0.19 vs. 1.52±0.33, 14-day PaO2(kPa): 10.23±1.01 vs. 5.87±0.95, 14-day Hyp (μg/mg): 2.31±0.04 vs. 3.12±0.06, 14-day TGF-β1 (integral A value): 15.46±2.89 vs. 29.72±4.27, all P < 0.01]. It was shown by Masson staining that in PQ model group, with the PQ-poisoned time prolonging, diffused pulmonary fibrosis and a large number of collagen deposition were observed gradually, and the most serious collagen deposition was observed at 14 days; after intervene of curcumin, pulmonary fibrosis was alleviated significantly at different time points as compared with the PQ model group. Conclusion Curcumin can enhance the pulmonary function by reducing the deposition of collagen fiber and inhabiting pulmonary fibrosis of PQ-poisoned rats.%目的 观察姜黄素对百草枯(PQ)中毒大鼠肺纤维化及肺功能的影响,探讨其可能的作用机制.方法 SPF级Wistar大鼠108只,按随机数字表法分为生理盐水(NS)对照组、PQ模型组和姜黄素干预组,每组再按不同时间点分为3、7、14 d 3个亚组,每个亚组12只.采用一次性灌胃PQ溶液50 mg/kg复制中毒模型;NS对照组灌胃等量NS.制模30 min后,姜黄素干预组一次性腹腔注射姜黄素200 mg/kg;NS对照组和PQ模型组注射等量NS.分别于3、7、14 d检测各组大鼠潮气量(VT);采集股动脉血进行血气分析.然后处死大鼠取肺组织,采用碱水解法测定羟脯胺酸(Hyp)含量;采用免疫组化法检测转化生长因子-β1(TGF-β1)蛋白表达;Masson染色后观察肺组织胶原纤维的分布及变化.结果 PQ染毒后,大鼠VT和动脉血氧分压(PaO2)均随时间延长呈进行性降低,而肺组织Hyp和TGF-β1水平均呈进行性升高,并分别于14 d达谷值或峰值,且明显低于或高于NS对照组相应时间点〔14 d VT(mL):1.52±0.33比2.81±0.47,14 d PaO2(kPa):5.87±0.95比14.15±1.02,14 d Hyp(μg/mg):3.12±0.06比1.14±0.05,14 d TGF-β1(积分A值):29.72±4.27比4.15±0.52,均P<0.01〕;姜黄素干预均能明显改善PQ大鼠上述各指标〔14 d VT(mL):2.34±0.19比1.52±0.33,14 d PaO2 (kPa):10.23±1.01比5.87±0.95,14 d Hyp(μg/mg):14 d为2.31±0.04比3.12±0.06,14 d TGF-β1(积分A值):15.46±2.89比29.72±4.27,均P<0.01〕.Masson染色显示:随染毒时间延长,PQ模型组肺组织逐渐出现弥漫性纤维化,有大量胶原纤维沉积,14 d胶原纤维沉积最严重;而姜黄素干预后各时间点肺纤维化程度均较PQ模型组明显改善.结论 姜黄素可通过减少PQ中毒大鼠肺组织胶原纤维沉积,抑制肺纤维化,改善肺功能.
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