Hepatoprotective and antioxidant effects of porcine plasma protein hydrolysates on carbon tetrachloride-induced liver damage in rats

Porcine plasma protein hydrolysate (PPH) prepared by alcalase for 5 h was fractioned by ultrafiltration. Four fractions, H-1 (MW > 10k), H-2 (MW 6-10k), H-3 (MW 3-6k) and H-4 (MW < 3k), were obtained. H-4 possessed the highest antioxidant activity as indicated by thiobarbituric acid-reactive substance values and hydroxyl radical scavenging activity (P < 0.01). Male rats were pretreated with H-4 at dose of 50, 100, and 200 mg/kg of body weight orally once daily for 12 days, then they were treated intraperitoneally with a single dose of CCl4 (2 mL/kg of body weight). The results showed that oral feeding of H-4 could significantly lower (P < 0.01) the serum levels of hepatic enzyme markers (aspartate transaminase and alanine transaminase). Compared with the CCl4-only treatment group, levels of hepatic superoxide dismutase, glutathione peroxidase, catalase and total antioxidant capacity were significantly increased, and the malondialdehyde levels were sharply decreased (P < 0.01) in rats treated by all doses of PPH fraction H-4. A histological examination of the liver showed that lesions, including necrosis, lymphocyte infiltration and fatty degeneration, were partially healed by treatment with H-4 fractions. These data suggest that in rats, PPH can protect the liver against CCl4-induced oxidative damage. (C) 2011 Elsevier Ltd. All rights reserved.