Development of a malnutrition model in mice: Comparative evaluation of food restriction percentage and different diets

Malnutrition is a complicated illness that affects people worldwide and is linked to higher death rates, a heightened vulnerability to infections, and delayed cognitive development. Experimental models have been constructed to comprehend the mechanisms associated with hunger. In this regard, the current study used two different types of food aiming to validate a murine model of malnutrition based on dietary restriction. The study was conducted with fifty-six Swiss male mice (eight-week-old) divided into eight groups (n=7 each) and fed the following experimental diets (10 weeks): Standard Diet (ST) ad libitum; ST 20% dietary restriction; ST 40% dietary restriction; ST 60% dietary restriction; AIN93-M diet ad libitum; AIN93-M 20% dietary restriction; AIN93-M 40% dietary restriction; AIN93-M 60% dietary restriction. Body, biochemical, and histological parameters were measured, and the restriction effects on genes related to oxidative stress (GPX1 and GPX4) in epididymal adipose tissue were evaluated. The results obtained showed that 20%, 40%, and 60% of dietary restrictions were able to reduce body weight when compared to controls, highlighting the accentuated weight loss in animals with 60% restrictions, especially those fed with AIN-93 M, which showed physical changes such as whitish skin and dull coat, voracious eating, and hunched posture. The present animal model also showed biochemical changes with hypoalbuminemia, as well as histological epididymal adipose tissue modulation. The presence of increased oxidative stress was observed when evaluating the GPX4 gene. Given the results, 60% food restriction using the AIN93-M diet was the best protocol for inducing malnutrition.