The application of adsorbent bentonite in oxidative stress induced by paraquat

Abstract

The protective effect of bentonite (natural and synthetic) in oxidative stress induced by paraquat was studied on 32 adult male Wistar rats. The animals were divided into four groups (n=8). The first group received only paraquat p.o. (via a gastric tube). An hour after administration of paraquat, the second and the third group were treated with natural and synthetic bentonite, respectively, while the fourth group was untreated (control). All three experimental groups were treated once a day, throughout 8 consecutive days. Blood samples were taken 0, 1, 4, 6 and 8 days after the beginning of the treatment. Oxidative stress induced by paraquat was estimated by means of catalase activity (CAT - mmol/H2O2/min/g Hb) and malondialdehyde quantity (MDA - nmol/g Hb). Oxidative stress proved to be significant an hour and 192 hours after the beginning of chronic intoxication by paraquat. Both natural and synthetic bentonite expressed a protective action from oxidative stress in the period from 24 h to 144 h post application, acting through the external capacity of cationic exchange, which is known to be approximately 10%. The absorption of paraquat depends on the size of the molecule and its polarisation and is performed by the mechanisms of ion exchange (ionic and electrostatic interaction). Nevertheless, both absorbents developed a significant protective effect (approximately 50 %) 1 h and 192 h after the first application of paraquat, indicating that these protectors act as molecular sieves and thus suppress the process of lipid peroxidation and the development of even more intensive oxidative stress.

U ovom radu su izneti rezultati proučavanja protektivnog efekta prirodnog i sintetskog bentonita tokom oksidativnog stresa indukovanog aplikacijom parahvata pacovima soja Wistar. Ogledne životinje su bile podeljene u četiri jednake grupe. Prva grupa pacova tretirana je samo parahvatom pomoću želudačne sonde. Jedan sat nakon aplikacije parahvata, pacovi druge i treće grupe su bili tretirani prirodnim ili sintetskim bentonitom, aplikovanim per os. Četvrta grupa pacova nije tretirana i služila je kao negativna kontrola. Eksperimentalne grupe životinja su bile tretirane jednom dnevno tokom osam uzastopnih dana. Uzorci krvi su uzimani 0, 1, 4, 6 i 8 dana nakon prvog tretmana. Stepen oksidativnog stresa je procenjivan na osnovu aktivnosti enzima katalaze i na osnovu količine malondialdehida. Prirodni i sintetski bentonit ispoljili su protektivnu aktivnost smanjivanjem parametara oksidativnog stresa u periodu od 24 do 144 sata nakon aplikacije. Autori predpostavljaju da bentonit deluje kao molekularno sito suprimirajući proces lipidne peroksidacije.