Long-term of a diet rich in saturated fats induced obesity, insulin resistance and microstructural alterations of the femurs in rat

• Autor(a) principal: Macena, Luan Pereira da
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
• Texto Completo: https://www.teses.usp.br/teses/disponiveis/25/25149/tde-24112021-153440/
• topic: Insulin Resistance; Microtomografia por Raio-X; Obesidade; Obesity; Osteoporose; Osteoporosis; Resistência à Insulina; X-Ray microtomography

In rodents and humans, dietary intake of large amounts of fat (HFD) has adverse effects on insulin sensitivity and the development of glucose intolerance and diabetes due to the type of fat consumed, the amount and time of consumption. Despite the indisputable role of obesity and insulin resistance over bone tissue, it is still not really known how much they interfere in the process of bone degradation, and what their relation is in the progression of structural changes. The purpose of the current work was to evaluate changes in body mass, insulin resistance and structural changes in rat femurs that received a high-fat diet (HFD). 6-week-old Wistar rats were divided into two groups: the group that consumed a standard diet (SD, n=16) and the group that received high fat (HFD, n=16). After 120 days of the diet, the animals\' femurs were subjected to X-ray microtomography and the condylar metaphyseal region evaluated in the CTAn program (SkyScan, Bruker). The data were submitted to the evaluation of the Gaussian distribution and homogeneity of variances for subsequent contrast of the averages by the t or Mann-Whitney test (p<0.05). HFD animals showed greater body mass compared to SD (926g vs. 670g, p<0.001) and insulin resistance with glucose tolerance (greater area on the curve in HFD), insulin tolerance (longer glucose decay time in DH). The X-ray microtomographic evaluation of the total volume (TV) of the evaluated metaphyseal region was similar between groups (p=0.3933), nevertheless the total volume of cortical was higher in HFD compared to SD (47.8mm3 vs. 33.61mm3, respectively, p<0.0001) and the TV of trabecular region was minor (73.1mm3 vs. 63.4mm3, respectively, p=0.0181), leading to the highest percentage of the cortical region (43.2% vs 30, 8%, respectively, p<0.0001). In the trabecular region, bone volume (BV) and bone surface (BS) were smaller in HFD than in SD (BV of mm3 18.6mm3 vs. 5.9mm3 p<0.0001) and BS of 178.5mm vs 314mm, respectively, 0=0.0021). Based on the results, the long-term consumption of a diet rich in saturated fat induce to obesity and insulin resistance which lead to structural changes in rat femurs similar to osteoporosis.