Abstract
AIM: To investigate the effects of salvianolic acid B (Sal B) on the morphological characteristics and functions of liver mitochondria of rats with nonalcoholic steatohepatitis (NASH). METHODS: A total of 60 male Sprague-Dawley rats were randomly divided into three groups: (1) a normal group fed a normal diet; (2) an NASH model group; and (3) a Sal B-treated group fed a high-fat diet. Two rats from each group were executed at the end of the 12th week to detect pathological changes. The rats in the Sal B-treated group were gavaged with 20 mL/kg Sal B (1 mg/mL) daily. The model group received an equal volume of distilled water as a control. At the end of the 24th weekend, the remaining rats were executed. Serum biochemical parameters and liver histological characteristics were observed. Malondialdehyde (MDA) and superoxide dismutase (SOD) in the liver were determined. Protein expression of CytC and caspase-3 was determined by immunohistochemistry. The mRNA transcripts of mitofusin-2 (Mfn2) and NF-κB in the liver tissue were detected by real-time PCR. Mitochondrial membrane potential was detected using a fluorescence spectrophotometer. Mitochondrial respiratory function was detected using a Clark oxygen electrode. RESULTS: The model group showed significantly higher ALT, AST, TG, TC and MDA but significantly lower SOD than the normal group. In the model group, the histological characteristics of inflammation and steatosis were also evident; mitochondrial swelling and crest were shortened or even disappeared. CytC (18.46 ± 1.21 vs 60.01 ± 3.43, P < 0.01) and caspase-3 protein expression (30.26 ± 2.56 vs 83.31 ± 5.12, P < 0.01) increased significantly. The mRNA expression of NF-κB increased (0.81 ± 0.02 vs 0.91 ± 0.03, P < 0.05), whereas the mRNA expression of Mfn2 decreased (1.65 ± 0.31 vs 0.83 ± 0.16, P < 0.05). Mitochondrial membrane potential also decreased and breathing of rats was weakened. Steatosis and inflammation degrees in the treatment group were significantly alleviated compared with those of the model group. In the treatment group, mitochondrial swelling was alleviated. CytC (60.01 ± 3.43 vs 30.52 ± 2.01, P < 0.01) and caspase-3 protein expression (83.31 ± 5.12 vs 40.15 ± 3.26, P < 0.01) significantly decreased. The mRNA expression of NF-κB also decreased (0.91 ± 0.03 vs 0.74 ± 0.02, P < 0.01), whereas the mRNA expression of Mfn2 increased (0.83 ± 0.16 vs 1.35 ± 0.23, P < 0.01). Mitochondrial membrane potential increased and respiratory function was enhanced. CONCLUSION: Sal B can treat NASH by protecting the morphological characteristics and functions of liver mitochondria, regulating lipid metabolism, controlling oxidative stress and lipid peroxidation and inhibiting apoptosis.