Faculty of Biological and Healthy Sciences, Federal University of the Jequitinhonha and Mucuri Valleys, Diamantina, MG, Brazil.
J Toxicol Sci. 2009 Dec;34(6):671-9. doi: 10.2131/jts.34.671.
Rats exposed to the quaternary herbicide paraquat (PQ) exhibit oxidative stress and lung injury. In the present study, we investigated the effect of multiple exposures to PQ on aerobic performance during progressive exercise on a treadmill in rats. PQ was dissolved in saline (SAL) (10 mg/ml) and administered intraperitoneally 7 mg/kg body wt to Wistar rats (n = 5) once a week for one month. Control rats received SAL (0.7 ml/kg body wt., intraperitoneally, n = 5) over the same time period. The animals were submitted to aerobic evaluation on a treadmill using a progressive protocol until fatigue prior to the administration of the first dose of PQ or SAL and repeated at 1 week and 40 days following the last dose of the herbicide. Twenty-four hours after the last performance tests, the animals were sacrificed, lungs removed and divided in two groups: PQ and SAL for histopathological analysis. The animals exposed to PQ exhibited decrease in aerobic performance and mechanical efficiency (ME) as well as increase in oxygen consumption during exercise in comparison to the controls forty days after the last dose of PQ. Lung histologic changes included atelectasis, interstitial edema, and inflammation cells in PQ group. The collagen system fibers, fraction area of alveolar collapse and influx of polymorphonuclear (PMN) cells in lung parenchyma were higher in PQ compared to SAL. In conclusion, multiple exposures to PQ induce pulmonary fibrosis, reduce the aerobic performance and mechanical efficiency and increase the metabolic cost of exercise in rats.
暴露于季铵除草剂百草枯（PQ）的大鼠表现出氧化应激和肺损伤。在本研究中，我们研究了多次接触 PQ 对大鼠在跑步机上进行渐进性运动时有氧表现的影响。将 PQ 溶解在生理盐水（SAL）（10mg/ml）中，并以 7mg/kg 体重的剂量腹腔内给予 Wistar 大鼠（n=5），每周一次，持续一个月。对照组大鼠在相同时间内接受 SAL（0.7ml/kg 体重，腹腔内）。在给予 PQ 或 SAL 第一剂之前，动物通过渐进式方案在跑步机上进行有氧评估，直至疲劳，然后在最后一剂除草剂后 1 周和 40 天重复进行。在最后一次性能测试后 24 小时，处死动物，取出肺脏并分为两组：PQ 和 SAL 进行组织病理学分析。与对照组相比，最后一次接触 PQ 四十天后，接触 PQ 的动物在运动过程中表现出有氧能力和机械效率（ME）下降，以及耗氧量增加。PQ 组的肺组织学变化包括肺不张、间质水肿和炎症细胞。与 SAL 相比，PQ 组的胶原系统纤维、肺泡塌陷分数面积和多形核（PMN）细胞在肺实质中的流入量更高。总之，多次接触 PQ 会导致大鼠肺纤维化，降低有氧能力和机械效率，并增加运动的代谢成本。
