ABSTRACT
OBJECTIVE To investigate the effect and mechanism of anwulignan on improving hepatic fibrosis in rats. METHODS Fifty SD rats were randomly divided into the normal group， model group， colchicine tablet group （0.1 mg/kg）， and anwulignan high-dose and low-dose groups （2.8 and 0.7 mg/kg）， with 10 rats in each group. Except for the normal group， all groups of rats were intraperitoneally injected with 50% CCl4 olive oil mixed solution to replicate the rat model of liver fibrosis. At the end of the modeling， rats in each group were given the corresponding drugs or distilled water intragastrically from the 9th week， once a day， for 4 weeks consecutively. During the experimental period， the general condition of the rats was observed； the liver index was calculated； the serum levels of alanine aminotransferase （ALT）， aspartate aminotransferase （AST）， superoxide dismutase （SOD） and malondialdehyde （MDA） were detected by colorimetric assay； the pathomorphology of the liver tissues and liver fibrosis were observed by HE staining and Masson staining； Western blot was used to detect the expression levels of phosphatidylinositol 3-kinase （PI3K）/protein kinase B （Akt） pathway and apoptosis-related proteins in liver tissues. RESULTS Compared with the normal group， the dietary amount of rats in the model group decreased， with sparse and disheveled fur， slow response， and a slower rate of weight growth or weight loss； the liver index was significantly increased （P＜0.01）； the serum levels of ALT， AST and MDA were significantly increased， and the SOD level was significantly decreased （P＜0.01）； HE and Masson staining showed that a large amount of fibrous proliferation was present in the liver tissues of the rats， and the collagen volume fraction was significantly increased （P＜0.01）； the protein expressions of PI3K， Akt， phosphorylated Akt and B-cell lymphoma （Bcl-2） were down-regulated significantly， while the protein expression of Bcl-2-associated X protein was increased significantly （P＜0.01）. Compared with the model group， the above indexes of the anwulignan high-dose and low-dose groups and the colchicine tablets group were all reversed significantly. CONCLUSIONS Anwulignan may reduce oxidative stress and inhibit hepatocyte apoptosis by activating the PI3K/Akt signaling pathway， and play the role of anti-hepatic fibrosis.
ABSTRACT
Excessive exercise makes the body consume more oxygen and produce excessive free radicals. The increased free radicals lead to oxidative stress injury and dysfunctions in liver tissue. Our previous study showed that Anwulignan, an active monomer in Schisandra sphenanthera Rehd. et Wils. (Schisandra), had anti-fatigue effects in mice. However, whether Anwulignan has a protective effect on liver damage in exhausted mice and the mechanism underlying remain elusive. An exhaustive swimming mice model was used to study the protective effects of Anwulignan on liver damage. The involvement of the nuclear factor (erythroid-derived 2)-like 2 (NRF2)/antioxidant responsive element (ARE) antioxidative pathway in Anwulignan-mediated anti-fatigue was analyzed using NRF2 inhibitor ML385 in HepG2 cells treated with H2O2. Animal welfare and experimental process follow the regulations of the Animal Ethics Committee of Beihua University. Anwulignan significantly lowered serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, reduced liver tissue damages, increased superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT), and decreased malondialdehyde (MDA) and 8-hydroxy-2 deoxyguanosine (8-OHdG) contents in the livers of exhausted mice, demonstrating a strong antioxidant effect. Furthermore, Anwulignan up-regulated the NRF2/ARE antioxidant pathway in liver tissue, increased B-cell lymphoma 2 (Bcl-2) expression, and decreased Bcl-2-like protein 4 (Bax) and caspase3 expression. In HepG2 cells, Anwulignan improved the cell viability and SOD activity, reduced reactive oxygen species (ROS) and MDA contents, up-regulated the expression of the NRF2/ARE signaling pathway and Bcl-2, and decreased Bax and caspase3 expression in the cells. Furthermore, pretreated ML385 partly abolished all these effects of Anwulignan. Anwulignan protects the liver from damage in the exhausted mice by its antioxidant effects and related to its activation of the NRF2 pathway.