α-Linolenic acid rich-chia seed improves glucose tolerance, modulates gluconeogenic pathway and hepatic insulin signaling in an experimental model of metabolic syndrome

Abstract

Metabolic dysfunction-associated steatotic liver disease (MASLD) is recognized as the hepatic manifestation of Metabolic Syndrome. The aim of this work was to evaluate the effects of chia seed, rich in α-linolenic acid, on glucose tolerance, enzyme activities and transcription factors involved in gluconeogenesis, and key molecules in insulin signaling in sucrose-rich diet (SRD) fed rats. Male Wistar rats were fed a reference diet (RD) for 6 months or a SRD for 3 months. Then, the latter group was randomly divided into two subgroups. One subgroup continued receiving SRD for up to 6 months and the other was fed with a SRD where chia seed was incorporated as a source of dietary fat for the next 3 months (SRD + CHIA). The results showed that chia seed improved glucose tolerance, reversed the increase in PEPCK, FBPase, and Glucose-6-Pase, and reduced the Glucose-6-Pase/GK ratio. Additionally, chia seed improved tAMPK and pAMPK protein levels, while maintaining GLUT-2 protein levels similar to those in the RD group. Under insulin stimulation, p-AKT protein levels were higher in the SRD + CHIA group than in the unstimulated group. IRS-1 and PGC-1α protein expression levels were similar among the three experimental groups. Liver FOXO-1 mRNA expression was decreased in the SRD + CHIA group. Finally, chia seed increased the n-3/n-6 ratio in hepatic membrane phospholipids. The present study demonstrated that chia seed modulate multiple mechanisms that enhance glucose metabolism and insulin signaling in SRD fed rats. These effects are mediated, at least in part, by the enrichment of n-3 PUFAs in liver tissue.

Keywords: Chia seed; Glucose metabolism; Hepatic insulin signaling; Sucrose-rich diet; n-3 PUFA.