Protective effect of β-sitosterol against high-fructose diet-induced oxidative stress, and hepatorenal derangements in growing female Sprague-Dawley rats

Abstract

BACKGROUND Chronic consumption of a high-fructose diet causes oxidative stress that compromises kidney and liver health. β-sitosterol (Bst), a phytosterol, is a functional nutrient with health benefits. β-sitosterol antioxidant activity protects the liver and kidney from ROS-mediated damage and lipid peroxidation. We evaluated the potential renoprotective and hepatoprotective effects of orally administrated β-sitosterol in high-fructose diet-fed growing female rats. Thirty-five 21-day old female Sprague-Dawley rat pups were randomly assigned to and administered the following treatments for 12 weeks: group I- standard rat chow (SRC) + plain drinking water (PW) + plain gelatine cube (PC); group II- SRC + 20% w/v fructose solution (FS) as drinking fluid + PC; group III- SRC + FS + 100 mg/kg body mass (BM) fenofibrate in gelatine cube; group IV- SRC + FS + 20 mg/kg BM β-sitosterol gelatine cube (Bst) and group V- SRC + PW + Bst. The rats were fasted overnight, weighed then euthanised. Blood was collected, centrifuged and plasma harvested. Livers and kidneys were excised, weighed and samples preserved for histological assessments. Plasma biomarkers of oxidative stress, liver and kidney function and renal tubular injury were assessed. RESULTS High fructose diet fed rats had increased plasma KIM-1, NGAL (p < 0.001) and MDA levels (p < 0.05). Dietary fructose caused microvesicular and macrovesicular steatosis, and reduced glomerular density, Bowman’s capsule area and urinary space. β-sitosterol protected against the high-fructose diet-induced hepatic steatosis and glomerular disturbances without adverse effects on liver and kidney function. CONCLUSIONS β-sitosterol, as a dietary supplement, could potentially be exploited to prevent high-fructose dietinduced NAFLD and to protect against high-fructose diet-induced renal tubular injury.