Banca de DEFESA: LETICIA SÃO JULIÃO SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : LETICIA SÃO JULIÃO SILVA
DATE: 26/10/2023
TIME: 14:00
LOCAL: meet.google.com/zee-eapv-kgj
TITLE:

Temporal effect of the cafeteria diet on the autonomic modulation of heart rate in Wistar rats

KEY WORDS:

Keywords: Heart rate rariability, Autonomic nervous system, Cardiovascular disease, Hypercaloric diet, Symbolic dynamics

PAGES: 100
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUMMARY:

few decades ago we have been going through a dietary change, with increased consumption of high-calorie foods, together with a decrease in physical activity, contributing to the increase in adiposity in the world population. Patients with high adiposity may develop chronic diseases, such as type 2 diabetes mellitus, hypercholesterolemia and cardiovascular disease (CVD). In studies, it has been shown that autonomic imbalance plays an important role in the pathogenesis of several CVDs, increasing the risk of cardiac death. Thus, the aim of the present study was to evaluate the temporal effect of a diet with high levels of carbohydrates and lipids on the cardiovascular autonomic modulation in rats through the analysis of the electrocardiogram (ECG) record by linear and non-linear methods. Wistar rats were fed for 24 days with ration supplemented with items of high caloric density and water added with sucrose (20%) or with commercial ration and water ad libitum. ECG electrodes were made and implanted in both groups of animals. Before the surgical procedure, the rats received a mixture of ketamine and xylazine, veterinary pentabiotic and meloxicam (doses adjusted with body weight). On days 6, 12, 18 and 24 of the diet, the ECG of the rats was recorded and at the end of the experiment linear analyzes were performed in the time domain [mean and standard deviation (SDNN) and the square root of the mean of the differences between consecutive RR intervals squared (RMSSD)] and in the frequency domain [low (LF) and high (HF) frequency spectral bands and the LF/HF ratio] and the analysis by non-linear methods, symbolic dynamics [variation patterns of families (0V, 1V, 2UV and 2LV)] and multiscale entropy (scales from 1 to 25 and scale groupings 1 to 5 and 6 to 25). Heart rate (HR), cardiac interval (CI) and body weight gain were also evaluated. Normalities were tested using the Shapiro-Wilk test and significant differences were analyzed using the two-way anova test, except for the analysis of multiscale entropy (EMS) and body weight, which was evaluated using Student's t test. Data were expressed as mean ± SEM (P<0.05). The present experiment was approved by the Ethics Committee for the Use of Animals of the UFSJ (protocol 32/2017). In rats fed the control diet, it was observed that its development induced a decrease in sympathetic activity on days 12 and 18 of the diet, evaluated by the 0V family of symbolic dynamics, and on day 24 in the 1V family of symbolic dynamics. The HR of the animals fed the control diet, during their development, had an increase in CI/decrease in HR. Animals fed the cafeteria diet showed an increase in HR/decrease in CI. An increase in the LF band (%) and in the LF/HF ratio from the 12th day on the diet was found in animals fed on the cafeteria diet, as well as in the 0V family of the symbolic dynamics and a reduction in the 2UV family in this period, in relation to the control rats. These data suggest an increase in sympathetic nervous system activity (HR, IC, LF, LF/HF, 0V) in animals treated with the cafeteria diet and a decrease in parasympathetic activity (2UV). The multiscale entropy was increased only on the 12th day of the diet in scales from 3 to 25. It is possible that the rats fed the cafeteria diet had a higher entropy value than the rats fed the control diet, with lower physiological complexity. It is possible to conclude that during the development of the rat there is a decrease in sympathetic activity and an increase in parasympathetic activity for the heart. The cafeteria diet offered to the rats blocks this effect from the 12th day of offering the diet, as a result, the sympathetic activity to the heart remains increased in these animals. Thus, the cafeteria diet offered to the rats for a short period of time is enough to alter cardiac sympathovagal balance.

BANKING MEMBERS:
Presidente - 1692875 - VALERIA ERNESTANIA CHAVES
Interna - 1716801 - CRISTIANE QUEIXA TILELLI
Externo à Instituição - LUIZ EDUARDO VIRGILIO DA SILVA