Banca de DEFESA: MARCOS VINICIUS DOS SANTOS SALES
Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.STUDENT : MARCOS VINICIUS DOS SANTOS SALES
DATE: 19/07/2023
TIME: 08:30
LOCAL: SALA DE PÓS-GRADUAÇÃO - PPGQB
TITLE:
Effects of mercury and derivatives on mitochondrial bioenergetics and oxidative stress in hypertension
KEY WORDS:
Hypertension; Mitochondria; Thimerosal; Oxidative stress.
PAGES: 69
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUMMARY:
Hypertension is a systemic disease that affects a large part of the world's population and its development does not have a single factor that serves as a “cause”. Environmental factors such as exposure to mercury species may be one of the reasons that trigger this condition. In this context, the mitochondria has a central role in the development of hypertension due to the oxidative stress that is mainly generated by it and this can be potentiated in the presence of mercury. Thimerosal (TM) is a mercury derivative present in vaccines and dermatological formulations as a preservative, which in an aqueous medium releases ethylmercury. Thus, we evaluated the effect of TM on mitochondrial bioenergetic parameters in spontaneously hypertensive rats (SHR) in two organs, liver and brain. The animals were divided into two groups; both were exposed for 24 h to TM (0.5 mg kg-1) or saline solution (control) in water. The electron transport chain (ETC) of isolated liver and brain mitochondria were evaluated using an oxygen electrode (Hansatech). Liver and brain mitochondrial integrity were analyzed by swelling and membrane potential. Mitochondrial oxidative and nitrosative stress were analyzed using DCF (nonspecific ROS), Amplex-red (H2O2) and DAF-FM (•NO). Finally, oxidative stress markers such as antioxidant enzyme activity (SOD and CAT), sulfhydryl content groups (SH), malondialdehyde content (MDA) and GSH/GSSG ratio were also quantified. The project was approved by CEUA (23/2021). Mitochondrial respiration experiments showed that using complex I as a substrate, the respiratory control (CR) of the exposed group to TM for the liver showed a decrease of 40% and for the brain a decrease of 23% when compared to the control group, however in the resting and uncoupled states, the treated group, for the liver, showed a better performance when compared to the control group (65 and 48%, respectively). On the other hand, for the brain, these results showed no significant difference. When evaluating mitochondrial integrity, liver membrane potential and swelling, were found no differences between groups. In the same line, in the liver, mitochondrial ROS generation and •NO showed no statistical difference between the groups. Liver SOD activity demonstrated a 59% decrease in its activity for the treated group when compared to the control group; on the other side, the other markers showed no difference between the groups. In the brain, no significant differences were found in mitochondrial integrity (membrane potential and swelling) between groups, as well as between mitochondrial ROS and •NO generation. Additionally, still in the brain, the activity of antioxidant enzymes SOD and CAT showed an increase of 100% and 83% for the treated group, respectively, however other stress markers such as SH and MDA showed a decrease of 46% and 41% , respectively, when comparing the treated to the controls. Our findings suggest that acute Thimerosal exposure negatively contributes to damage of mitochondrial integrity and functionality, being responsible for ETC uncoupling.
BANKING MEMBERS:
Externo(a) à Instituição - ALICE VALENÇA ARAÚJO
Presidente - 2022362 - ANA CATARINA REZENDE LEITE
Interno(a) - 1613338 - JOSUE CARINHANHA CALDAS SANTOS
Interno(a) - 2120103 - MARILIA OLIVEIRA FONSECA GOULART