Study of dietary curcumin on the restorative effect of liver injury induced by carbon tetrachloride in common carp, Cyprinus carpio

Abstract

Carbon tetrachloride (CCl4) can be decomposed into free radicals, which cause lipid peroxidation, thereby damaging liver cells, and resulting in the death of aquatic animals. The present study was to investigate the recovery effect and possible mechanism of dietary curcumin against liver injury in Cyprinus carpio induced by CCl4. The experiment was divided into four groups. Two control groups were fed with a basal feed (the negative control, P1 and the positive control, P2), and two treatment groups were fed with feeds supplemented with 120 and 240 mg kg−1 for the entire 10-week study duration, respectively (P3 and P4). At the end of the feeding period, the CCl4 solution (CCl4 was dissolved in olive oil at 30 %, 0.5 mL per 100 g body weight) was injected into the abdominal cavity of P1, P3 and P4 groups. And the P2 group was injected with olive oil in the same proportion. On days 2, 3, 5 and 7 after CCl4 challenge, samples were taken separately to investigate the effect of curcumin on the liver injury induced by CCl4 in fish. Results showed that plasma alanine transaminase (ALT)and aspartate aminotransferase (AST) avtivities of fish increased significantly, relative to pre-challenge levels, 2 day after CCl4-challenge in P1, P3 and P4 groups (P<0.05), and the avtivities of plasma ALT and AST in these groups decreased as challenge time from 2 day to 7day. Liver total superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities and glutathione (GSH) content of fish in P1, P3 and P4 groups decreased firstly and then increased with increasing challenge time, however, the content of liver malondiadehyde (MDA) was contrary. Curcumin (120 mg kg-1 curcumin per feed) inhibited the damage of liver tissue structure caused by CCl4 and made liver tissue structure return to normal. Meanwhile, dietary curcumin supplementation could also increase the live nuclear factor crythroid 2-related factor 2 (Nrf2) mRNA level and Nrf2 protein level in the liver nucleus, especially 120 mg kg-1 feed. Overall, the results indicated that feed supplemented with curcumin could effectively protect the liver against CCl4 induced injury. And the 120 mg kg−1 curcumin group had the better restorative effect of liver injury compared with the high-dose group.