Alleviation of hepatic steatosis accompanied by modulation of plasma and liver TNF-alpha levels by Trigonella foenum graecum (fenugreek) seeds in Zucker obese (fa/fa) rats.

Objective: Oral supplements of fenugreek (Trigonella foenum graecum) seeds (Fen) have been shown to treat glucose and lipid homeostasis in several metabolic disorders; however, its ability to alleviate obesity-associated pathologies is not known. The main objective of this study was to evaluate the effect of Fen in Zucker obese rats (Ob), an animal model of obesity and related disorders, such as dyslipidemia and hepatic steatosis.
Methods: Female Zucker (6-week-old) Ob and lean (Ln) rats were randomly grouped (n = 8 rats/group) to receive either basal or 5% Fen-supplemented AIN-93G diets for 8 weeks, and then were euthanized. Histopathology and biochemical parameters in the liver together with plasma biochemistry were assessed.
Results: Obese rats had significantly higher (P < 0.05) body and liver weight, as well as plasma insulin, lactate, cholesterol, triglyceride and tumor necrosis factor (TNF)-alpha compared to their Ln counterparts. Fen significantly reduced (P < 0.05) the liver-weight of Ob rats in comparison to Ob rats fed basal diet (Control), while no effect was observed in the Ln rats. Fen treatment resulted in a lower P-value (P < 0.05). In addition, Ob rats on Fen-supplemented diets had fasting plama cholesterol and TNF-alpha levels, and significantly higher (P < 0.05) triglycerides in comparison to the control rats. Hepatic triglyceride level was significantly lower (P < 0.05) in Ob rats fed Fen supplemented diets in comparison to control. The levels of bound and soluble liver TNF-alpha (26 and 17 kDa, respectively) and TNF receptor-II (TNFR-II, 75 kDa) proteins were significantly lower (P < 0.05) in Ob than in Ln rats. Fen significantly lowered (P < 0.05) both the soluble and bound forms of TNF-alpha protein while significantly elevating (P < 0.05) TNFR-II in the livers of Ob rats compared to Ob Controls.
Conclusion: These results demonstrate unequivocally that in a short-term preclinical evaluation, dietary Fen supplementation reduced the triglyceride accumulation in the liver, a hallmark feature of hepatic steatosis without affecting the plasma insulin or glucose levels in Zucker obese rats and suggest that TNF-alpha may play an important role in this process.