Dietary glucosinolates inhibit splenic inflammation in high fat/cholesterol diet-fed C57BL/6 mice

HyunJi Gu; Min-Hee Gwon; Sang-Min Kim; Jung-Mi Yun

doi:10.4162/nrp.2021.15.6.798

Dietary glucosinolates inhibit splenic inflammation in high fat/cholesterol diet-fed C57BL/6 mice

Nutr Res Pract. 2021 Dec;15(6):798-806. doi: 10.4162/nrp.2021.15.6.798. Epub 2021 May 18.

Authors

HyunJi Gu¹, Min-Hee Gwon², Sang-Min Kim¹, Jung-Mi Yun¹

Affiliations

¹ Department of Food and Nutrition, Chonnam National University, Gwangju 61186, Korea.
² Department of Education, Graduate School of Education, Chonnam National University, Gwangju 61186, Korea.

Abstract

Background/objectives: Obesity is associated with chronic inflammation. The spleen is the largest organ of the lymphatic system and has an important role in immunity. Obesity-induced inflammatory responses are triggered by Toll-like receptor (TLR)-myeloid differentiation primary response 88 (MyD88) pathway signaling. Phenethyl isothiocyanate (PEITC) and 3,3'-diindolylmethane (DIM), major dietary glucosinolates present in cruciferous vegetables, have been reported to produce anti-inflammatory effects on various diseases. However, the effects of PEITC and DIM on the obesity-induced inflammatory response in the spleen are unclear. The purpose of this study was to examine the anti-inflammatory effects of PEITC and DIM on the spleen and their mechanism in high fat/cholesterol diet (HFCD)-fed C57BL/6 mice.

Materials/methods: We established an animal model of HFCD-induced obesity using C57BL/6 mice. The mice were divided into six groups: normal diet with AIN-93G diet (CON), high fat diet (60% calories from fat) with 1% cholesterol (HFCD), HFCD with PEITC 30 mg/kg/day or 75 mg/kg/day (HFCD+P30, HFCD+P75), and HFCD with DIM 1.5 mg/kg/day or 7.5 mg/kg/day (HFCD+D1.5, HFCD+D7.5). Enzyme-linked immunosorbent assay was used to evaluate pro-inflammatory cytokine secretion. Western blot and quantitative polymerase chain reaction were used to analyze protein and mRNA levels of nuclear factor kappa B (NF-κB) p65, interleukin 6 (IL-6), cyclooxygenase 2 (COX-2), TLR2, TLR4, and MyD88 in spleen tissue.

Results: Serum IL-6 levels were significantly higher in the HFCD group than in groups fed a HFCD with PEITC or DIM. Levels of NF-κB p65 protein and TLR2/4, MyD88, NF-κB p65, IL-6, and COX-2 mRNA were significantly higher in the HFCD group than in the CON group and were reduced by the PEITC and DIM supplements.

Conclusions: PEITC- and DIM-supplemented diets improved splenic inflammation by modulating the TLR2/4-MyD88 pathway in HFCD-fed mice. We suggest that dietary glucosinolates may at least partially improve obesity-induced inflammation of the spleen.

Keywords: Glucosinolates; Toll-like receptors; inflammation; obesity; spleen.