Protective effects of leucine against lipopolysaccharide-induced inflammatory response in Labeo rohita fingerlings.

Abstract

The present study investigated the protective effects of leucine against lipopolysaccharide (LPS)-induced inflammatory responses in Labeo rohita (rohu) in vivo and in vitro. Primary hepatocytes, isolated from the hepatopancreas, were exposed to different concentrations of LPS for 24 h to induce an inflammatory response, and the protective effects of leucine against LPS-induced inflammation were studied. Finally, we investigated the efficiency of dietary leucine supplementation in attenuating an immune challenge induced by LPS in vivo. Exposure of cells to 10-25 μg mL(-1) of LPS for 24 h resulted in a significant production of nitric oxide and release of lactate dehydrogenase to the medium, whereas cell viability and protein content were reduced (p < 0.05). LPS exposure (10 μg mL(-1)) increased mRNA levels of the pro-inflammatory cytokines TNF-α, IL-1β and IL-8 in vitro (p < 0.05). However, pretreatment with leucine prevented the LPS-induced upregulation of TNF-α, IL-1β and IL-8 mRNAs by downregulating TLR4, MyD88, NF-κBp65, and MAPKp38 mRNA expression. Interestingly, mRNA expression of the anti-inflammatory cytokine, IL-10, which was increased by LPS treatment, was further enhanced (p < 0.05) by leucine pretreatment. The enhanced expression of IL-10 might inhibit the production of other pro-inflammatory cytokines. It was found that leucine pretreatment attenuated the excessive activation of LPS-induced TLR4-MyD88 signaling as manifested by lower level of TLR4, MyD88, MAPKp38, NF-κBp65 and increased level of IκB-α protein in leucine pre-treatment group. In vivo experiments demonstrated that leucine pre-supplementation could protect fish against LPS-induced inflammation through an attenuation of TLR4-MyD88 signaling pathway. Taken together, we propose that leucine pre-supplementation decreases LPS-induced immune damage in rohu by enhancing the expression of IL-10 and by regulating the TLR4-MyD88 signaling pathways.

• Authors: Sib Sankar Giri, Shib Sankar Sen, Jin Woo Jun, Venkatachalam Sukumaran, Se Chang Park
• Journal: Fish & shellfish immunology (Fish Shellfish Immunol) Vol. 52 Pg. 239-47 (May 2016) ISSN: 1095-9947 [Electronic] England
• PMID: 27016401 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2016 Elsevier Ltd. All rights reserved.

Chemical References

• Lipopolysaccharides
• Leucine

Topics

• Animal Feed (analysis)
• Animals
• Cyprinidae (immunology)
• Diet (veterinary)
• Dietary Supplements
• Fish Diseases (immunology)
• Hepatocytes (drug effects, immunology)
• Inflammation (immunology, veterinary)
• Leucine (administration & dosage, metabolism)
• Lipopolysaccharides (pharmacology)
• Signal Transduction (drug effects)