[Sulforaphane alleviates acute liver injury induced by diquat in mice by activating Keap1/Nrf2 signaling pathway].

OBJECTIVE

To investigate the protective effect and possible mechanism of sulforaphane (SFN) on acute liver injury in mice induced by diquat (DQ) poisoning.

METHODS

Forty-eight male C57BL/6 mice were divided into Control group, DQ model group (DQ group), SFN intervention group (DQ+SFN group), and SFN control group (SFN group) using a random number table method, with 12 mice in each group. Acute liver injury mice model was established by one-time intraperitoneal injection of 1 mL of 40 mg/kg DQ solution at once. SFN group was injected with 1 mL of ddHO. After 4 hours of molding, 0.5 mL of 5 mg/kg SFN solution was injected into the peritoneal cavity of the DQ+SFN group and SFN group, once daily for 7 consecutive days. DQ group and Control group were injected with an equal amount of ddHO. Then, the mice were euthanized to collect liver tissue and blood samples, and the levels of plasma biomarkers alanine aminotransferase (ALT) and aspartate aminotransferase (AST), as well as oxidative stress indicators such as superoxide dismutase (SOD), glutathione (GSH), and malondialdehyde (MDA) in liver tissue were measured. The changes of liver structure were observed under transmission electron microscopy. The apoptosis and reactive oxygen species (ROS) level in liver tissue were observed under fluorescence microscope. Western blotting was used to detect the protein expressions of nuclear factor E2-related factor 2 (Nrf2), hemeoxygenase-1 (HO-1), Kelch-like ECH-associated protein 1 (Keap1), and cleaved caspase-9 in liver tissue.

RESULTS

Compared with the Control group, the liver mitochondria in the DQ group showed severe swelling, partial dissolution of the matrix, and cristae rupture and loss; the levels of plasma AST and ALT significantly increased, the MDA content in the liver increased, the activities of SOD and GSH decreased, the level of ROS significantly increased, the number of apoptotic cells in the liver significantly increased, the protein expressions of Nrf2 and HO-1 significantly decreased, and the protein expressions of Keap1 and cleaved caspase-9 significantly increased. Compared with the DQ group, the mitochondrial damage in the DQ+SFN group was reduced, the levels of plasma AST and ALT were significantly reduced [ALT (U/L): 58.22±4.39 vs. 79.94±3.32, AST (U/L): 177.64±8.40 vs. 219.62±11.60, both P < 0.01], the liver MDA content decreased, and the activities of SOD and GSH increased [MDA (μmol/g: 5.63±0.18 vs. 5.96±0.29, SOD (kU/g): 102.05±4.01 vs. 84.34±5.34, GSH (mmol/g): 16.32±1.40 vs. 13.12±1.84, all P < 0.05], the production of ROS in liver tissue was significantly reduced [ROS (fluorescence intensity): 115.90±10.89 vs. 190.70±10.16, P < 0.05], and apoptotic cells were significantly reduced (cell apoptosis index: 4.39±1.00 vs. 10.71±0.56, P < 0.01), the protein expressions of Nrf2 and HO-1 were significantly increased, while the protein expressions of Keap1 and cleaved caspase-9 were significantly decreased (Nrf2/β-actin: 1.15±0.04 vs. 0.93±0.05, HO-1/β-actin: 1.75±0.12 vs. 0.78±0.04, Keap1/β-actin: 1.00±0.14 vs. 1.28±0.13, cleaved caspase-9/β-actin: 1.31±0.12 vs. 1.81±0.09, all P < 0.05). However, there was no statistically significant difference in various indicators between the SFN group and the Control group.

CONCLUSIONS

SFN can activate the Keap1/Nrf2 signaling pathway to alleviate DQ induced acute liver injury in mice.