DcpCiitiiiciiI of Piiciiinology m d Alleipy, In\rirutc ol I n k i n c i l Medicine. M e d i ~a l IJnivcr\iiy of L o d ~. P o l d Kc\ n o i d \ p,irqu,it. anihrcjxol, hqdrofen peroxide. lipid peroxidallon
Paraquat (Pq) is a herbicide which is very toxic to all animals and to man. It generates free radicals and leads to acute or chronic lung injury and usually to death. So far, the role of lipid peroxidation of cell membranes in the mechanism of its toxicity has not been proved satisfactorily and therefore in the prewnt study we examined the Concentration of hydrogen peroxide ( H L 0 2 ) and various lipid peroxidation products (LPP) such as conjugated dienes (CD), lipid hydroperoxides (LH), malonyldialdehyde (MDA) and Schiff bases in selected organs of the rat given a single intraperitoneal dose 35 nig kg ' Pq. We also evaluated the influence of a mucolytic and probably antioxidant drug, ambroxol, on Pq-induced changes in the concentration of H,O, and LPP. Paraquat increased the hepatic concentration of HzOz, CD, I,H and MDA by approximately fourfold. Though the dose of Pq was nearly twice the I.D.,' dose, we did not notice any changes in the concentration of these substances in the critical organ, lung or heart and kidney. Ambroxol alleviated the increase of H,O, in the liver but did not reduce the concentration of LPP. Moreover, the drug administered alone induced lipid peroxidation in the liver. Our results indicate that Pq does not induce HzOz production and lipid peroxidation in the lung but it increases the concentration of H z 0 2 and LPP in the liver. Ambroxol inhibits the Pqinduced increase in the concentration of H,O, in the liver without protecting it against lipid peroxidation. Moreover, the drug alone may act as a pro-oxidant.