Banca de QUALIFICAÇÃO: LETICIA SÃO JULIÃO SILVA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : LETICIA SÃO JULIÃO SILVA
DATE: 16/12/2022
TIME: 14:00
LOCAL: meet.google.com/tjs-rrxg-qri
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: 76
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUMMARY:

The diet of the world's population has changed, currently a greater amount of processed foods, preservatives, sugar, sodium, carbohydrates, etc. is consumed. This dietary change in recent years, together with the decrease in physical activity, contributes to the increase in adiposity in the world population. In recent years, in addition to the adult population presenting more obese individuals, the child population also followed the same pattern. With increased consumption of this diet, risk factors related to cardiovascular disease increased. Patients exposed to a hypercaloric diet can develop several pathologies, which can be metabolic, such as metabolic syndrome, and cardiovascular, such as coronary disease, cerebrovascular diseases, peripheral arterial disease, rheumatic heart disease, congenital heart disease, deep vein thrombosis, pulmonary embolism, etc. In studies, it has been shown that autonomic imbalance plays an important role in the pathogenesis of several cardiovascular diseases, increasing the risk of cardiac death. Thus, the aim of the present study was to evaluate the effect of a hypercaloric, hyperlipidic and hyperglycemic diet on cardiovascular autonomic modulation in rodents through the analysis of electrocardiogram (ECG) recordings 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. Electrodes for ECG were made and implanted in rats in the control and cafeteria groups. Before the surgical procedure, the rats received a mixture of ketamine and xylazine, veterinary pentabiotic and meloxicam, the doses being adjusted according to the animal's body weight. On days 6, 12, 18 and 24, 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 square of successive differences (RMSSD)] and in the frequency domain [low (LF) and high (HF) frequency spectral bands and the LF/HF ratio] and the analyzes by nonlinear methods, namely symbolic dynamics [family variation patterns ( 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. Results were expressed as mean ± standard error and analyzed by Student's t-test (P<0.05). The present experiment was approved by the Ethics Committee for the Use of Animals of the UFSJ (protocol 32/2017). As a result of the experiments, we found that the HR and CI of the cafeteria rats were altered from the 12th day on the diet. It Abstract viii was possible to observe an increase in HR and a decrease in CI in cafeteria rats, a result indicative of increased sympathetic activity. We found an increase of approximately 60% in the LF band and a 100% increase in the ratio of the LF/HF bands in relation to the control, suggesting an increase in the activity of the sympathetic nervous system in the animals treated with the cafeteria diet. An increase in the percentage of occurrence of the 0V family of symbolic dynamics was observed, while the 2UV family was reduced. It is known that the 0V family corresponds to sympathetic modulation and the 2UV family to vagal modulations, thus confirming the findings in the linear methods. 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. Literature data suggest that this happens in a system degraded by cardiovascular diseases. We can observe a relationship between the results of the linear and nonlinear analyses, which is important for affirming the results found. On the 24th day of offering the cafeteria diet, the change in HR, the LF band and the increased LF/HF ratio, and the 0V and 2UV family of altered symbolic dynamics, confirm previous findings from our laboratory. However, after only 12 days of diet, the rats already show indicators of changes in cardiac sympathovagal balance.

BANKING MEMBERS:
Presidente - 1692875 - VALERIA ERNESTANIA CHAVES
Interna - 1716801 - CRISTIANE QUEIXA TILELLI
Externo à Instituição - DANIEL PENTEADO MARTINS DIAS - CUBM