Study of the Effects of Flaxseed (Linum usitatissimum L.) on Aspartame- Induced Kidney Damage in Male Rats

Abstract

Background: Aspartame is one of the most common artificial non-nutritive sweeteners consumed in many parts of the world, and an increasing volume of experimental evidence associates its long-term ingestion with organ damage through oxidative-stress-mediated mechanisms including renal injury. Flaxseed (Linum usitatissimum L.) is a source of lignan and α-linolenic-acid/oilseed that has proven to be an effective antioxidant and anti-inflammatory agent which can offset such injury. Aim: This experiment was aimed to investigate the therapeutic benefits of dietary flaxseed against aspartame-induced nephrotoxicity in male albino rats. Methods: A total of forty adult male rats were randomly divided into four groups (n = 10/group), and treated for eight weeks as follows: Group 1,normal control; Group 2, high dose aspartame (40 mg/kg body weight/day); Group 3,flaxseed (10% dietary supplementation) and Group 4, aspartame plus flaxseed combined. We assessed body weight, food and water intake, urine output, absolute and relative kidney weights, various serum renal-function biomarkers (urea, creatinine, uric acid), 24-hour urinary protein as well as markers of renal oxidative-stress/antioxidant indices (i.e., malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) along with excess reduced glutathione(GSH)). Results: Aspartame administration significantly increased serum urea, creatinine, uric acid, urinary protein, relative kidney weight and renal MDA as compared to control (p <0.05) and decreased the activities of SOD CAT GPx and GSH in comparison with control (p < 0.05). Flaxseed, when co-administered with aspartame significantly alleviated these disturbances and brought renal function markers and antioxidant enzyme activities back toward control values but did not fully normalize them. Flaxseed alone had no differences versus control for most of the parameters and, numerically, better performance as compared to control for several oxidative markers. In conclusion, flaxseed supplementation provides significant but partial protection against aspartame-induced nephrotoxicity in male rats via reduction of oxidative stress and preservation of renal antioxidant defenses.