Protective effects of paeonol against lipopolysaccharide-induced liver oxidative stress and inflammation in gibel carp (Carassius auratus gibelio)

Paeonol (2′-hydroxy-4′-methoxyacetophenone) is a phenol that exhibits antioxidant and anti-inflammatory capabilities. In this study, the underlying mechanism of paeonol against LPS-induced oxidative stress and inflammatory responses in gibel carp was investigated. Three hundred healthy gibel carp were divided into five groups ( n  = 9), intraperitoneally injected with LPS and thereafter treated with paeonol (16 mg/kg and 64 mg/kg). Fish were anesthetized with MS-222 (100 mg/L), and samples were collected at 72 h to investigate plasma biochemical indexes, liver histopathology , antioxidant enzymatic activity , and TLR receptor-related gene expression. Fish injected with LPS (20 mg/kg) exhibited significantly increased plasma aminotransferase (ALT), aminotransferase (AST), lactate dehydrogenase (LDH), glucose (GLU), diamine oxidase (DAO), and alkaline phosphatase (ALP) levels ( P  < 0.05). In addition, LPS challenge significantly enhanced myeloperoxidase (MPO) and malondialdehyde (MDA) contents, whereas those of catalase (CAT) and glutathione peroxidase (GSH-Px) decreased ( P  < 0.05). However, treatment with paeonol attenuated these LPS-induced changes ( P  < 0.05). The mRNA expression of TLR4 , TIRAP , MyD88 , TRAF6 , NF-κB, TNF-α, IL-1β, and IL-8, which were activated by LPS challenge ( P  < 0.05), were downregulated by paeonol. Additionally, histopathological examination demonstrated that paeonol alleviates LPS-induced hepatic tissue lesions in fish. Taken together, the results suggest that paeonol mitigates LPS-induced liver oxidative stress and inflammation in gibel carp.