Search

Sitagliptin is known for its anti-diabetic activity though it has other pleiotropic pharmacological actions. Its effect against concanavalin A (Con A)-induced hepatic fibrosis has not been investigated yet. Our target was to test whether sitagliptin can suppress the development of Con A-induced hepatic fibrosis and if so, what are the mechanisms involved? Con A (6 mg/kg) was injected once weekly to male Swiss albino mice for four weeks. Sitagliptin was daily administered concurrently with Con A. Results have shown the potent hepatoprotective activity of sitagliptin against Con A-induced hepatitis and fibrosis. That was evident through the amelioration of hepatotoxicity serum parameters (ALT, AST, ALP, and LDH) and the increase in the level of serum albumin in sitagliptin treated mice. Simultaneously, there was amendment of the Con A-induced hepatic lesions and repression of fibrosis in sitagliptin-treated animals. Hydroxyproline, collagen content and the immuno-expression of the fibrotic markers, TGF-β and α-SMA were depressed upon sitagliptin treatment. Sitagliptin suppressed Con A-induced oxidative stress and increased antioxidants. RT-PCR analysis showed enhancement of mRNA expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and its target genes (GCLc, GCLm, NQO-1, HO-1) by sitagliptin. Furthermore, sitagliptin ameliorated the level and immuno-expression of nuclear factor kappa-B (NF-κB) alongside the immuno-expression of the inflammatory cytokine, TNF-α. Taken together, this study demonstrates the hepatoprotective activity of sitagliptin which may be in part related to enhancement of Nrf2 signaling pathway and inhibition of NF-κB which interact inflammatory response in liver. Sitagliptin might be a new candidate to suppress hepatitis-associated fibrosis., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Recently, there is an increasing interest in searching for harmless natural products isolated from plant materials that can be used as beneficial dietary supplements and/or therapeutic drug candidates. The present study aimed to test the potential protective role of Pulicaria petiolaris (PP, Asteraceae) against hepatic and cardiotoxic effects associated with lipopolysaccharide (LPS) injection. PP was given orally for 5 days at two different doses before LPS injection. Results have shown that LPS induced remarkable hepatic and cardiac injurious effects in mice. Hepatic damage was evident through increased serum transaminases, lactate dehydrogenase (LDH), alkaline phosphatase (ALP), and activity. Estimation of high levels of serum creatine kinase-MB (CK-MB) and cardiac troponin I indicated cardiac damage. Histopathological examination of liver and heart confirmed the biochemical results. Increase in oxidative stress along with a depressed antioxidant status of liver and heart were observed in LPS-intoxicated animals. Furthermore, LPS induced activation of nuclear factor-κB (NF-κB) and subsequent elevation of inflammatory cytokines (TNF-α, IL-6). On the other hand, PP treatment successfully safeguards both organs against LPS-induced injury as indicated by the improvement of the biochemical and histopathological parameters. These results suggest that PP ameliorates LPS-induced hepatic and cardiac oxidative injurious effects via antioxidant and anti-inflammatory effects.

Background/aims: Phosphodiesterase-5 inhibitors have beneficial effects in multiple liver diseases possibly through the reduction of oxidative stress and inflammatory response. However, these effects have not yet been examined in cholestatic liver dysfunction. Hence, this study aimed to explore the ability of vardenafil, a known phosphodiesterase-5 inhibitor, to repress lithocholic acid (LCA)-induced cholestatic liver injury and investigate the possible molecular pathways., Methods: Male Swiss albino mice were treated with LCA (0.125 mg/g) twice daily for 7 days to induce cholestatic liver damage. Vardenafil was administered 3 days before and throughout the administration of LCA. Serum markers of hepatotoxicity and hepatic nitro-oxidative stress along with antioxidant parameters were measured, and the histopathology of liver tissues was assessed. The expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and its target genes was examined using PCR. The activation of nuclear factor kappa-B (NF-κB) and the levels of inflammatory cytokines were determined. NLRP3 inflammasome and its components were studied by PCR and western blot., Results: LCA induced marked cholestatic liver damage as demonstrated by increased serum transaminases, alkaline phosphatase (ALP), lactate dehydrogenase (LDH), bilirubin, and bile acids. Examination of liver specimens confirmed the biochemical results. Nitro-oxidative stress parameters were significantly elevated along with reduced antioxidant capacity in hepatic tissue following LCA administration. LCA suppressed Nrf2 and its target genes and decreased the mRNA expression and binding capacity of Nrf2 as well as the mRNA expression of GCLm, GCLc, Nqo1, and HO-1. Additionally, LCA enhanced the activation of NF-κB, which was accompanied by elevations of inflammatory cytokines. Importantly, LCA induced the activation of NLRP3 inflammasome. LCA increased the expression of NLRP3, ASC, caspase-1, and IL-1β genes and proteins in hepatic tissue. The activities of IL-1β and caspase-1 were increased in the LCA group. Interestingly, vardenafil ameliorated LCA-induced hepatic injury and alleviated all biochemical, histopathological, and inflammatory parameters., Conclusions: These data elucidated the effects of Nrf2 inhibition and NLRP3 inflammasome activation in LCA-induced liver injury. The hepatoprotective activity of vardenafil in LCA-induced cholestatic damage may result from the drug's ability to activate Nrf2 signaling and prevent the activation of NLRP3, which could suppress the inflammatory responses in hepatic tissue. Thus, vardenafil can be considered a novel anti-inflammatory remedy for cholestatic liver damage., (© 2018 The Author(s). Published by S. Karger AG, Basel.)

Vardenafil is a selective phosphodiesterase-5 inhibitor used for erectile dysfunction treatment. The hepatoprotective role of vardenafil against acute hepatitis is not reported yet. Hence, this study aims to explore the protective role of vardenafil against concanavalin A (Con A) induced acute liver injury. Mice were pretreated with vardenafil (0.17 mg/kg/day) for seven consecutive days, and then subjected to a single IV injection of Con A. The results demonstrated that the vardenafil pretreatment significantly reduced the elevated serum levels of transaminases and alkaline phosphatase. Histopathological examination showed marked necrosis and inflammation in Con A-treated mice which was significantly ameliorated in vardenafil pretreated animals. Vardenafil pretreatment significantly alleviated the expression of nuclear factor kappa-B and inducible nitric oxide synthase in the hepatic tissue. Additionally, serum levels of nitric oxide and tumor necrosis factor-alpha were decreased in vardenafil pretreated animals compared to the Con A group. Therefore, our results demonstrate that vardenafil has hepatoprotective effect and this could be linked to decrease inflammatory mediators., (© 2016 Wiley Periodicals, Inc.)

Objectives: This study aimed to evaluate the potential protective effects of pirfenidone (PFD) against concanavalin A (Con A)-induced hepatitis in mice., Methods: Autoimmune model of hepatitis was established using single intravenous injection of Con A. Mice were randomly assigned into four groups as follows: control group; Con A group; and two groups, receiving PFD in two dose levels (200, 300 mg/kg) for 5 days before Con A administration. Extent of hepatitis was studied using biochemical, histopathological and immunohistochemical estimations., Key Findings: Hepatitis was clearly evident through extensive hepatocellular lesions and elevated levels of serum transaminases, alkaline phosphatase and lactate dehydrogenase. Con A induced an imbalance between oxidant and antioxidant status in the hepatic tissue. Furthermore, Con A significantly elevated hepatic nuclear factor kappa B (NF-κB) expression and inflammatory cytokines levels (tumour necrosis factor-alpha, interleukin-6 and nitric oxide). PFD pretreatment potently ameliorated all these pathological changes., Conclusions: Pirfenidone hepatoprotective activity may be mediated through its antioxidant ability that suppresses NF-κB activation signalling pathways suggesting that PFD may be a new candidate for treatment of acute hepatitis., (© 2016 Royal Pharmaceutical Society.)

Aflatoxin B(1) is a potent hepatotoxic and hepatocarcinogenic mycotoxin. Lipid peroxidation and oxidative DNA damage are the principal manifestations of aflatoxin B(1)-induced toxicity that could be counteracted by antioxidants. Many plant constituents have been reported to prevent liver damage associated with lipid peroxidation. In this study, curcumin (polyphenolic antioxidant purified from turmeric) and resveratrol (polyphenol obtained from grapes) were evaluated for possible protection against liver injury induced by aflatoxin B(1) in rats. Adult male Fischer rats were divided into six groups including untreated control, curcumin control (200 mg/kg BW), resveratrol control (10 mg/kg BW) and aflatoxin B(1) (25 microg/kg BW). Other two groups were administered either curcumin or resveratrol along with aflatoxin B(1). The study was carried out for 90 days. At the end of the experiment period, blood and tissue samples were collected from the animals before they were killed. Livers were collected for histopathologic studies and fixed in 10% buffered formalin solution. Serum was used for estimation of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyl transferase (gamma-GT) enzymes. The lipid peroxidation, reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were estimated in liver homogenates. The results revealed that aflatoxin B(1) administration caused liver damage as indicated by statistically significant (P < 0.05) increase in serum ALT, AST and gamma-GT levels. In addition, there were general statistically significant reductions in the activities of GSH, SOD, CAT, GSH-Px, and an increase in lipid peroxidation in the liver of aflatoxin B(1)-treated group compared to the untreated control group. Curcumin showed a significant hepatoprotective activity by lowering the levels of serum marker enzymes, lipid peroxidation and elevating the levels of GSH, SOD, CAT and GSH-Px. However, resveratrol failed to protect from the aflatoxin B(1)-induced liver injury. These findings suggest that curcumin but not resveratrol has a hepatoprotective effect against aflatoxin B(1)-induced liver injury.