Antioxidative effect of wheat-grain moxibustion on cyclophosphamide-induced liver injury in mice based on Nrf2-Keap1 signaling pathway

Abstract

To observe the protective effect of wheat-grain moxibustion on cyclophosphamide (CTX)-induced liver injury in mice, and explore its mechanism based on the nuclear factor E2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) signaling pathway. Twenty-four male CD-1 (ICR) mice were randomly divided into a blank group, a model group, and a moxibustion group, with 8 mice in each group. The mice in the model group and the moxibustion group were intraperitoneally injected with CTX (80 mg/kg) to induce liver injury. The mice in the moxibustion group were treated with wheat-grain moxibustion at "Guanyuan" (CV 4) and bilateral "Zusanli" (ST 36) and "Sanyinjiao" (SP 6), with each acupoint being treated by 3 cones, approximately 30 seconds per cone, once daily for 7 days. After intervention, the general condition of the mice was observed; the liver mass was measured and the liver index was calculated; HE staining was used to observe the morphology of the liver, and the liver tissue pathological score was assessed; ELISA was used to detect the serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), glutamate dehydrogenase (GLDH) and the levels of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) in the liver; Western blot and real-time fluorescence quantitative PCR were used to detect the protein and mRNA expression of Nrf2, Keap1, and quinione acceptor oxidoreductase 1 (NQO1) in the liver. Compared with the blank group, the mice in the model group showed sluggishness, unsteady gait, and decreased body weight; liver index was increased (P<0.01); liver cells were loosely arranged, with a small number of cell swollen and exhibiting balloon-like changes; liver tissue pathological score was increased (P<0.05); the serum levels of AST, ALT, GLDH, and level of MDA in the liver were increased (P<0.05), and the levels of SOD and GSH-Px in the liver were decreased (P<0.05); protein and mRNA expression of Nrf2 and NQO1 in the liver was decreased (P<0.01), protein and mRNA expression of Keap1 in the liver was increased (P<0.01). Compared with the model group, the mice in the moxibustion group showed improvement in general condition; liver index was decreased (P<0.01); liver cell structure was relatively intact and clear, and liver tissue pathological score was decreased (P<0.05); the serum levels of AST, ALT, GLDH, and level of MDA in the liver were decreased (P<0.05), and the levels of SOD and GSH-Px in the liver were increased (P<0.05, P<0.01); protein and mRNA expression of Nrf2 and NQO1 in the liver was increased (P<0.05), protein and mRNA expression of Keap1 in the liver was decreased (P<0.05). The wheat-grain moxibustion may alleviate CTX-induced liver injury by activating the Nrf2-Keap1 signaling pathway and enhancing the expression of antioxidative enzyme system in the body.