The protective effect of juglanin on fructose-induced hepatitis by inhibiting inflammation and apoptosis through TLR4 and JAK2/STAT3 signaling pathways in fructose-fed rats

Biomed Pharmacother. 2016 Jul:81:318-328. doi: 10.1016/j.biopha.2016.04.013. Epub 2016 Apr 23.

Abstract

High fructose-feeding is an essential causative factor leading to the development and progression of hepatitis associated with high levels of endotoxin (LPS). Juglanin, as a natural compound extracted from the crude Polygonum aviculare, displayed inhibitory activity against inflammation response and cancer growth. However, researches about its role on anti-inflammation and apoptosis are far from available. Here, it is the first time that juglanin was administrated to investigate whether it inhibits fructose-feeding-induced hepatitis in rats and to elucidate the possible mechanism by which juglanin might recover it. Fructose-feeding rats were orally administrated with juglanin of 5, 10 and 20mg/kg for 6 weeks, respectively. Juglanin exerted prevention of fructose-feeding-stimulated increased LPS levels, accelerated alanine transaminase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP) and up-regulated inflammatory cytokines expression in serum, mainly including tumor necrosis factor-alpha (TNF-a), Interleukin 1beta (IL-1β), Interleukin 6 (IL-6) and Interleukin 18 (IL-18). Meanwhile, toll-like receptor 4 (TLR4)-modulated mitogen-activated protein kinase (MAPK)/nuclear factor kappa B (NF-κB) and apoptosis-related Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway are involved in the progression of hepatic injury and inflammation. And juglanin was found to suppress fructose-feeding-induced activation of these signaling pathways compared with the model group administrated only with fructose. These results indicate that juglanin represses inflammatory response and apoptosis via TLR4-regulated MAPK/NF-κB and JAK2/STAT3 signaling pathway respectively in rats with hepatitis induced by LPS for fructose-feeding. Treatment of juglanin might be an effective therapeutic strategy for preventing hepatitis.

Keywords: Hepatitis; Inflammation; JAK2/STAT3 signaling pathway; Juglanin; TLR4.

MeSH terms

  • Animals
  • Apoptosis* / drug effects
  • Cytokines / metabolism
  • Feeding Behavior
  • Fructose
  • Glycosides / pharmacology
  • Glycosides / therapeutic use*
  • Hepatitis / drug therapy*
  • Hepatitis / pathology
  • Inflammation / complications
  • Inflammation / drug therapy*
  • Janus Kinase 2 / metabolism*
  • Kaempferols / pharmacology
  • Kaempferols / therapeutic use*
  • Liver / drug effects
  • Liver / injuries
  • Liver / pathology
  • Male
  • Mitogen-Activated Protein Kinases / metabolism
  • NF-kappa B / metabolism
  • Phosphorylation / drug effects
  • Protective Agents / pharmacology
  • Protective Agents / therapeutic use
  • Rats, Sprague-Dawley
  • STAT3 Transcription Factor / metabolism*
  • Signal Transduction
  • Toll-Like Receptor 4 / metabolism*

Substances

  • Cytokines
  • Glycosides
  • Kaempferols
  • NF-kappa B
  • Protective Agents
  • STAT3 Transcription Factor
  • Toll-Like Receptor 4
  • juglanin
  • Fructose
  • Janus Kinase 2
  • Mitogen-Activated Protein Kinases