Date on Senior Honors Thesis

3-2024

Document Type

Senior Honors Thesis

Cooperating University

University of Louisville

Department

Biology

Committee Chair

Barati, Michelle

Committee Member

Corbitt, Cynthia

Committee Member

Thompson, Lee

Author's Keywords

sodium benzoate; preservatives; histology; kidney; oxidative stress

Abstract

Sodium Benzoate (SB) is a commonly utilized food preservative with potential therapeutic uses for neurological conditions such as Alzheimer’s disease and hepatic encephalopathy. Consumption of SB is generally regarded as safe (GRAS), by the Food and Drug Administration, at amounts of 0.1% by weight of food. However, previous reports indicate that SB exposure may induce histological alterations in kidney structures and promote oxidative stress. Thus, with increasing obesity rates and fatty diets, the effects of SB coupled to a high fat diet (HFD) remain to be determined. This study addressed the hypothesis that SB with a HFD will increase extracellular matrix production and alter anti-oxidative regulators and enzymes in kidneys of female and male mice. 5-week-old male and female mice were assigned to either control diet (CD) or high fat diet (HFD, 21% fat) for 6 weeks, then received SB (99mg/kg) or sterile water, by gavage, for 4 additional weeks. Kidney sections from 3 mice in each experimental group were stained with Picro-Sirius red stain for histologic analysis of kidney morphology. Western blots were conducted to measure abundance of superoxide dismutase (SOD-1), glutamyl-cysteine synthetase (GCS), and fibronectin. Data were analyzed by three-way ANOVA. Kidneys of male had significant decrease in abundance of GCS, compared to female mice. Histological measurements reported largely no significant differences in collagen staining between groups, however this finding has numerous limitations. These findings suggest that exposure to a high fat diet with SB may reduce protective measures against oxidative stress, a characteristic consistent with kidney disease. Future studies will continue to analyze these mouse replicates to examine histological changes in the extracellular matrix of the juxtamedullary region, as well as additional regulatory pathways.

Lay Summary

Sodium Benzoate (SB) is a commonly utilized food preservative with potential therapeutic uses for neurological conditions such as Alzheimer’s disease and hepatic encephalopathy. Consumption of SB is generally regarded as safe (GRAS), by the Food and Drug Administration, at amounts of 0.1% by weight of food. However, previous reports indicate that SB exposure may injure kidneys. With increasing obesity rates and fatty diets, the effects of SB coupled to a high fat diet (HFD) remain to be determined. This study addressed the hypothesis that SB with a HFD will increase kidney fibrosis (scarring) and alter protective anti-oxidative mechanisms in kidneys of female and male mice. 5-week-old male and female mice were assigned to either control diet (CD) or high fat diet (HFD, 21% fat) for 6 weeks, then received SB (99mg/kg) or sterile water, by gavage, for 4 additional weeks. Kidneys were stained with a solution to show collagen fibers, production of which increase in kidney disease. Abundance of 3 proteins were examined: superoxide dismutase (SOD-1), glutamyl-cysteine synthetase (GCS), and fibronectin. Kidneys of male had significant decrease in abundance of GCS, compared to female mice, suggesting that male mice may be more susceptible to oxidative stress. Collagen fibers associated with fibrosis, were higher in female mice. These findings suggest that exposure to a high fat diet with SB may reduce protective measures against oxidative stress, a characteristic consistent with kidney disease.

Download

Included in

Biology Commons

Share

COinS