Effects of a diet rich in refined carbohydrates on the vascular reactivity of rat aortas
Name: KAROLINE NEUMANN GOMES
Publication date: 13/03/2025
Examining board:
Name |
Role |
|---|---|
| ANDRE SOARES LEOPOLDO | Examinador Interno |
| ANDRESSA BOLSONI LOPES | Coorientador |
| KAROLINI ZUQUI NUNES | Presidente |
| PATRICIA MORAES FERREIRA NUNES | Examinador Externo |
Summary: The excessive consumption of refined carbohydrates has been increasing
worldwide and is associated with inflammation and oxidative stress, both of
which are risk factors for the development of cardiovascular diseases. This
study aims to investigate the effects of a diet rich in refined carbohydrates on
the vascular reactivity of aortic rings. Adult male Wistar rats (8–10 weeks old,
approximately 300 g) were acclimated for 2 weeks and randomly assigned to
two experimental groups: the Control group (CT) and the High-Carbohydrate
Diet group (HCD). The CT group was fed a standard laboratory chow
(Nuvilab®) for 15 days, while the HCD group received a diet consisting of 45%
condensed milk, 10% refined sugar, and 45% diet chow. Following the
treatment period, body and biochemical parameters, glucose and insulin
tolerance tests, aortic vascular reactivity, and the expression of genes related to
inflammation (MCP-1, CD86, and iNOS) and SOD activity were evaluated. The
results showed that the HCD group presented elevated fasting blood glucose
and triglyceride levels, as well as increased glucose tolerance test values at
time 0 and at 15 and 30 minutes after glucose injection. In the insulin tolerance
test, HCD animals showed an increase only at 3 minutes following
intraperitoneal insulin administration. No significant changes were observed in
body mass, adiposity, or cholesterol levels compared to the control group.
Regarding vascular reactivity, the HCD group exhibited a reduced
vasoconstrictor response to phenylephrine in aortic rings without PVAT.
Endothelial removal enhanced the vasoconstrictor response to phenylephrine,
suggesting the involvement of endothelial factors. Incubation with L-NAME
indicated increased NO production in the HCD group, while incubations with
Aminoguanidine, Tiron, DETCA, and TEA suggested greater involvement of
iNOS, reactive oxygen species, SOD, and K+ channels, respectively.
Furthermore, the HCD group showed increased gene expression of iNOS and
inflammatory markers, along with elevated SOD activity. The presence of
perivascular adipose tissue (PVAT) did not influence vascular reactivity
between the groups. These findings indicate that a diet rich in refined
carbohydrates, even in the short term, can induce inflammation, oxidative
stress, and endothelial dysfunction, thereby increasing the risk of cardiovascular
disease.
