Effects of a blend of green tea and curcuma extract supplementation on lipopolysaccharide-induced inflammation in horses and ponies

Janine Starzonek; Katja Roscher; Matthias Blüher; Dominique Blaue; Carola Schedlbauer; Manuela Hirz; Jens Raila; Ingrid Vervuert

doi:10.7717/peerj.8053

Effects of a blend of green tea and curcuma extract supplementation on lipopolysaccharide-induced inflammation in horses and ponies

PeerJ. 2019 Nov 12:7:e8053. doi: 10.7717/peerj.8053. eCollection 2019.

Authors

Janine Starzonek¹, Katja Roscher², Matthias Blüher³, Dominique Blaue¹, Carola Schedlbauer¹, Manuela Hirz⁴, Jens Raila⁵, Ingrid Vervuert¹

Affiliations

¹ Institute of Animal Nutrition, Nutrition Diseases and Dietetics, Leipzig University, Leipzig, Saxony, Germany.
² Equine Clinic, Internal Medicine, Justus-Liebig-University Giessen, Giessen, Hesse, Germany.
³ Division of Endocrinology and Nephrology, Department of Medicine, Leipzig University, Leipzig, Saxony, Germany.
⁴ Institute of Veterinary Pathology, Justus-Liebig-University Giessen, Giessen, Hesse, Germany.
⁵ Institute of Nutritional Science, University of Potsdam, Nuthetal Bergholz-Rehbrücke, Brandenburg, Germany.

Abstract

Background: In horses and ponies numerous medical conditions are known to be linked with inflammation in different tissues, especially in the liver. Besides affecting other metabolic pathways such as the expression of certain interleukins (IL), inflammation is associated with stress of the endoplasmic reticulum (ER). In particular, ER stress leads to adaptive stress response and can be measured by several markers of inflammatory and stress signalling pathways, like nuclear factor κB (NF-kB).

Objectives: To investigate lipopolysaccharide (LPS)-induced inflammatory reactions and their modulation in horses and ponies by feeding a polyphenol-rich supplement consisting of green tea and curcuma.

Methods: In a cross-over study, 11 animals were allocated to either a placebo or a supplement group and supplemented with 10 g of a blend of green tea and curcuma extract (GCE) or a placebo (calcium carbonate) once daily. After 21 days of supplementation, all animals underwent a LPS challenge to induce moderate systemic inflammation. Blood samples and liver biopsies were taken at standardized time points: 24 hours before and 12 hours after LPS challenge. Inflammatory blood parameters such as serum amyloid A (SAA), haptoglobin and retinol binding protein 4 (RBP4) were measured in serum. Hepatic mRNA levels of selected markers of inflammation such as haptoglobin, tumor necrosis factor α (TNF-α), IL-1β, IL-6, cluster of differentiation 68 (CD68), fibroblast growth factor 21 (FGF-21), NF-κB, activating transcription factor 4 (ATF4) were quantified by RT-qPCR. In addition, liver biopsies were examined histologically for inflammatory alterations.

Results: Blood markers of acute inflammatory response increased after LPS challenge. In the liver, the proinflammatory cytokine IL-1β showed significantly lower mRNA levels after LPS challenge in the supplemented group (P = 0.04) compared to the placebo group. Levels of the hepatic CD68 mRNA increased significantly in the placebo group (P = 0.04). There were no significant differences between supplemented and placebo groups concerning other markers of inflammation and markers of ER stress within the liver. The number of hepatic macrophages were not different after LPS challenge in both feeding groups.

Conclusion: LPS was able to induce inflammation but seemed less suitable to induce ER stress in the horses and ponies. The polyphenol-rich supplement showed some potential to reduce inflammatory responses. Nevertheless, the supplementation did not exert an overall anti-inflammatory effect in horses and ponies.

Keywords: Catechin; Curcumin; ER-stress; Equines; Polyphenols.

Grants and funding

This work was supported by Kaesler Nutrition GmbH. Support was also received from Leipzig University within the program of Open Access Publishing. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.