Alpha lipoic acid exerts antioxidant effect via Nrf2/HO-1 pathway activation and suppresses hepatic stellate cells activation induced by methotrexate in rats.

Hepatic injury is a major side effect associated with methotrexate (MTX) therapy resulting from inflammatory reactions and oxidative stress induction. Therefore, liver fibrosis incidence is augmented with long-term MTX therapy. Alpha lipoic acid (ALA) is a naturally occurring compound with potent antioxidant activity. This study explored the hepatoprotective mechanisms of ALA against MTX-induced hepatic injury in rats. Hepatic injury was induced in MTX group by 20 mg/kg body weight ip. injection of MTX. ALA group was pretreated with ALA 60 mmol/kg body weight ip. for five days followed by a single dose of MTX in the sixth day. Blood samples and liver tissues were then obtained to assess several biochemical parameters as serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), reduced glutathione (GSH), total antioxidant capacity (TAC) and lipid peroxidation. Nuclear factor E2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) pathway was studied by determining the extent of mRNA Nrf2 expression and the level of HO-1. Hepatic stellate cells (HSCs) activation was evaluated by estimating the expression of α-smooth muscle actin (α-SMA) and hydroxyproline content. Also, tumor necrosis factor alpha (TNF-α), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and caspase-3 were assessed by ELISA in addition to histopathological examination of liver samples. Results showed that ALA pretreatment improved liver function since serum ALT, AST and ALP levels were reduced. Additionally, ALA restored GSH and TAC levels when compared to MTX group and decreased lipid peroxidation. ALA exerted its antioxidant effect via Nrf2/HO-1 pathway as well as it showed anti-inflammatory and antiapoptotic effects by reducing TNF-α, iNOS, COX-2 and caspase-3 levels in liver tissue homogenate. Finally, ALA suppressed HSCs activation by decreasing α-SMA expression and hydroxyproline content in liver. It was concluded that ALA has hepatoprotective effects against MTX-induced hepatic injury mediated by Nrf2/HO-1 pathway as well as anti-inflammatory and antiapoptotic properties.

Fayez AM ，Zakaria S ，Moustafa D 《-》

Protective effect of ethyl acetate fraction of Drynaria quercifolia against CCl(4) induced rat liver fibrosis via Nrf2/ARE and NFκB signalling pathway.

Drynaria quercifolia rhizome is traditionally used as hepatoprotective drug especially in chronic jaundice. The present study was undertaken to scientifically evaluate the efficacy of D. quercifolia rhizome against liver fibrosis. D. quercifolia rhizome crude extract (DQ) and its fractions of hexane (HDQ), ethyl acetate (EDQ), butanol (BDQ) were evaluated in vitro using primary hepatocytes and RAW 264.7 cells. In vivo anti-liver fibrotic activity of EDQ was assessed using CCl4 induced liver fibrosis in Wistar rats and serum biochemical parameters (AST, ALT, ALP, SB, cholesterol), MDA, PT, INR, GSH, SOD, CAT, liver glycogen, serum albumin levels were monitored. qRT-PCR analysis of TNF-α, COX-2, iNOS were performed. ELISA method was used to estimate TNF-α, COX-1 & 2. Histopathological studies like H & E, Masson's trichrome, immunohistochemistry staining for α-SMA, TIMP-1, Nrf2 were conducted. LC-Q-TOF-MS analysis of EDQ was conducted. In vitro activity guided fractionation of D. quercifolia revealed EDQ as active fraction when compared to other extracts. EDQ treatment significantly inhibited the expression of α-SMA, TIMP-1, COX-2, TNF-α, iNOS and increased the levels of Nrf2 in rat liver fibrosis. LC-Q-TOF-MS analysis of EDQ confirmed the presence of naringin and naringenin. The anti-liver fibrotic activity of EDQ is via inhibition of NFκB signalling pathway, antioxidant response through Nrf2 activation and further inhibition of HSC activation.

Anuja GI ，Shine VJ ，Latha PG ，Suja SR ... -  《-》

Pomegranate reverses methotrexate-induced oxidative stress and apoptosis in hepatocytes by modulating Nrf2-NF-κB pathways.

The clinical efficacy of the widely used chemotherapeutic drug methotrexate (MTX) is limited due to its associated hepatotoxicity. Pomegranate polyphenols are of huge health benefits and known to possess remarkable antioxidant properties capable of protecting normal cells from various stimuli-induced oxidative stress and cell death. In this study, we explored the protective role of pomegranate fruit extract (PFE) in ameliorating MTX-induced hepatic damage. Male Swiss albino mice exposed to MTX (20 mg/kg body weight) exhibited distinct markers of toxicity such as increased activities of enzymes alanine transaminase, aspartate transaminase, lactate dehydrogenase and alkaline phosphatase and also increased oxidative stress in liver evidenced by increased ROS generation and lipid peroxidation. Decrease in reduced glutathione levels, superoxide dismutase, catalase, hepatic heme oxygenase 1 and NQO-1 activities were also observed. Tracing the signal transduction pathways, it was seen that MTX exposure significantly increased nuclear translocation of NF-κB coupled with increase in phosphorylated Iκ-B and down-regulation of NF-kappaB-dependent antiapoptotic protein Bcl-2. Treatment with MTX increased the expression of the apoptotic enhancer Rho/Cdc42 as well as the phosphorylation of SAPK/JNK. A shift in the Bax/Bcl-2 ratio towards apoptosis and increase in the caspase 3 level was also evident. Administration of PFE for 7 consecutive days before and after MTX challenge suppressed MTX-induced cell death, mitigated the injurious effects of MTX and offered protection against apoptosis. PFE was shown to reduce ROS generation in hepatocytes by activating the Nrf2-ARE pathway and inhibiting NF-κB as a consequence of which the antioxidant defense mechanism in the liver was up-regulated, thereby conferring protection against MTX-induced hepatotoxicity and apoptosis.

Mukherjee S ，Ghosh S ，Choudhury S ，Adhikary A ，Manna K ，Dey S ，Sa G ，Das T ，Chattopadhyay S ... -  《-》

Antioxidant properties of red raspberry extract alleviate hepatic fibrosis via inducing apoptosis and transdifferentiation of activated hepatic stellate cells.

Hepatic fibrosis is a wound-healing process caused by prolonged liver damage and often occurs due to hepatic stellate cell activation in response to reactive oxygen species (ROS). Red raspberry has been found to attenuate oxidative stress, mainly because it is rich in bioactive components. In the current study, we investigated the inhibitory effects and associated molecular mechanisms of red raspberry extract (RBE) upon activated hepatic stellate cell (aHSC) in cellular and rat models. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were increased in the dimethylnitrosamine (DMN)-applied samples, whereas treatment of RBE significantly suppressed the activities of these enzymes. In addition, a histopathological analysis demonstrated that RBE could substantially diminish the hepatic collagen content and alpha-smooth muscle actin (α-SMA) expression induced by DMN. Administration of 250 μg/mL RBE could also arrest the growth and enhance the apoptosis of activated HSC-T6 cells, which was accompanied with elevated levels of activated caspases and poly (ADP-ribose) polymerase (PARP) cleavage. Particularly, RBE application remarkably abolished oxidative damage within the cells and reduced the carbonylation of proteins, which was attributed to the upregulation of catalase, nuclear factor erythroid 2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1). Moreover, the knockdown of Nrf2 together with the RBE treatment synergistically abrogated the expression of α-SMA and promoted the level of peroxisome proliferator-activated receptor gamma (PPAR-γ), suggesting that RBE could mitigate the transdifferentiation of HSC in a Nrf2-independent manner. These findings implied that the application of RBE could effectively remove oxidative stress and relieve the activation of HSC via modulating the caspase/PARP, Nrf2/HO-1 and PPAR-γ pathways, which may allow the development of novel therapeutic strategies against chemical-caused liver fibrogenesis.

Wu TH ，Wang PW ，Lin TY ，Yang PM ，Li WT ，Yeh CT ，Pan TL ... -  《-》

Berberine ameliorates methotrexate-induced liver injury by activating Nrf2/HO-1 pathway and PPARγ, and suppressing oxidative stress and apoptosis in rats.

Berberine (BBR) is a natural isoquinoline alkaloid with very impressive health benefits. It is one of the most effective natural supplements available; however, its ameliorative mechanism against methotrexate (MTX)-induced liver injury is not well defined. This study investigated the protective effect of BBR against MTX hepatotoxicity, focusing on its ability to attenuate oxidative stress and apoptosis and to activate nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling and peroxisome proliferator activated receptor gamma (PPARγ). Rats received BBR (25 and 50mg/kg) orally for 7days before MTX injection. Other groups received MTX followed by BBR (25 and 50mg/kg) orally for 7 days. MTX-induced rats showed significant body weight loss, increased serum liver function marker enzymes, bilirubin and tumor necrosis factor alpha (TNF-α). Liver lipid peroxidation, nitric oxide (NO) and caspase-3 were significantly increased following MTX administration. BBR supplemented either before or after MTX significantly ameliorated body weight, liver function markers, TNF-α, lipid peroxidation, NO and caspase-3. BBR increased serum albumin and liver antioxidant defenses in MTX-induced rats. Histological and immunohistochemical examination showed improved histological structure and decreased expression of Bax in liver of MTX-induced rats treated with BBR. In addition, BBR up-regulated Nrf2, HO-1 and PPARγ expression in the liver of MTX-induced rats. In conclusion, BBR attenuated MTX-induced oxidative stress and apoptosis, possibly through up-regulating Nrf2/HO-1 pathway and PPARγ. Therefore, BBR can protect against MTX-induced liver injury.

Mahmoud AM ，Hozayen WG ，Ramadan SM 《-》