OriginatArticle Paraquat ( PQ ) - induced exercise metabolic cost , pulmonary fibrosis increases reducing aerobic performance in rats

Rats exposed to the quaternary herbicide paraquat (PQ) exhibit oxidative stress and lung irijury.'In the present study, we investigated the effect ofmultiple exposures to PQ on aerobic perfbrmance during progressive exercise on a treadmiU in rats. PQ was dissolved in saline (SAL) (1O mgfml) and administered intraperitoneally 7 mglkg body wt to Wistar rats (n = 5) once a week for one month, Control rats received SAL (O.7 mltkg body wt., intraperitoncally, n =t 5) over the sarne time period. The animals were subrnjtted to aerobic evaluation on a treadmi] [ using a progressive protocol until 'fatigue prior to the administration of the first dose ofPQ or SAL and repeated at 1 week and 40 days fbllowing the last dose ofthe herbicide. Twenty-fbur hours after the last performunce tests, the animals were sacrificcd, lungs removed and divided in two groups: PQ and SAL thr histopathologicat analysis. The animals exposed to PQ exhibited decrease in aerobic perfbrmance and mechanical ernciency (ME) as well as increase in oxygen consumption during exercise in comparison to the controls fbrty days after the last dose ofPQ. Lung histologic ehanges included atelectasis, interstitial ederna, and inflammation cells in PQ group. The collagen system fibers, fraction area ofalveolar collapse and infiux ofpolymorphonuclear (PMN) cells in 1ung parenchyma were higher in PQ compared to SAL. In conclusion. multiple exposures to PQ induce pulmonary fibrosis, reduce thc aerobic performance and mechanical effciency and increase the metabolic cost ofexercise in rats.