Effects of different fatty acids on lipid metabolism and oxidative stress in C57/BL mice fed a high fat diet and rich in fructose

Author(s)

Camila Sanches Manca

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC)
• Defense date: 2017-06-30

Examining board members

Alceu Afonso Jordao Junior; Rejane Maira Góes; Cleni Mara Marzocchi Machado

• Advisor: Alceu Afonso Jordao Junior

Abstract

The Non-alcoholic fatty liver is related to the increasing causes of morbidity and mortality of liver diases. Its incidence is related to obesity and comorbidities linked to it, in which it has awaked great interest in the research. The disease is associated to genetic predisposition, lack of physical activity and high intake of saturated fats and fructose. Quantitative modulation of the diet may promote or retard the pathology. Thus, therapies aimed at delaying or decreasing non alcoholic hepatic steatosis could alleviate liver damage, improve liver function and reduce its progression. The objectives of the present study were: to evaluate the consumption of vegetable oils rich in commercially available MUFAs and PUFAs in the prevention or reduction of hepatic steatosis by analyzing parameters of hepatic and serum lipid metabolism, oxidative stress and delaying the progression of NAFLD. Material and Methods: animals were divided into the following groups: Control (n = 10) + HLF * (n = 10); Group HLF * AZ (n = 10); Group HLF * CN (n = 10); Group HLF * S (n = 10). After 16 weeks of diet and treatment with the respective oils, the animals were anesthetized and blood was withdrawn by cardiac puncture and tissues for further analysis. Results: The supply of a diet rich in saturated fat (lard) + fructose caused an increase in weight in the HLF group while the administration of the respective vegetable oils was able to delay the weight gain. Liver weight and sum of epididymal and retroperitoneal adipose tissues were higher in HLF while there was a significant reduction in HLF / S hepatic weight. Retroperitoneal tissue was lower in HLF / CN. In general, treatment with the respective vegetable oils decreases steatosis in all experimental groups. The supply of extra virgin olive oil did not reflect weight gain, but the group had a significant increase in serum TG and VLDL, with a decrease in serum cholesterol. Histologically it reduced the steatosis score when compared to the HLF being classified as mild to moderate macro and microvesicular steatosis. Soybean oil presented a higher amount of PUFAs, being rich in n-6, reflected in the maintenance of animal weight, decreased steatosis, being classified as mild steatosis when compared to HLF, but increased serum cholesterol. He presented an increase of MDA and decrease of hepatic GSH. Canola oil due to its content of PUFAs (n-6 and n-3) had greater incorporation of EPA and DHA than appear to have been positively evidenced. There was no alteration in the biochemical parameters and presented lower accumulation of liver fat through the analysis of the percentage of liver fat and histopathology, being characterized as mild steatosis. By the lipid peroxidation presented a greater accumulation of MDA, but an increase of GSH. However, the supply of the respective oils had a positive influence on different physiological mechanisms. (AU)

• FAPESP's process: 15/01348-6 - Effects of fatty acids of vegetable oils on lipid metabolism and oxidative stress in rats fed high-fat diet rich in fructose
• Grantee: Camila Sanches Manca
• Support Opportunities: Scholarships in Brazil - Master