Name: THIAGO FERNANDES DE OLIVEIRA
Publication date: 01/12/2022
Advisor:
Name |
Role |
|---|---|
| ALESSANDRA SIMAO PADILHA | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| ALESSANDRA SIMAO PADILHA | Advisor * |
| IVANITA STEFANON | Internal Examiner * |
| LEONARDO DOS SANTOS | Internal Examiner * |
| MARCELO PERIM BALDO | External Examiner * |
| PRISCILA ROSSI DE BATISTA | External Examiner * |
Summary: Introduction: Exposure to Cd is associated with several cardiovascular diseases,
such as atherosclerosis and arterial hypertension, probably by inducing oxidative
stress and vascular dysfunction. Cardiovascular diseases are the major causes
of death in the world and the higher prevalence in men increased the possibility
of women of childbearing age to present a protection of the cardiovascular
system, probably due to the action of female sex hormones. As studies of the
effects of Cd on the vasculature were carried out in males, it is not known whether
females would have vascular function affected by exposure to this metal.
Objective: To analyze the effects of chronic exposure to 100 ppm cadmium
chloride on the vascular function of male and female Wistar conductance arteries.
Material and Methods: The experiments were performed on 3-month-old male
and female Wistar who received cadmium chloride (CdCl2 100 mg/L in drinking
water for 30 days) or vehicle (filtered water). Before the start of exposure and at the end of it, data on systolic blood pressure and weight of the animals were
recorded. After 30 days of exposure to the metal, the animals were euthanized
and blood was collected for the dosage of cadmium and estrogen, and thoracic
aorta, for the evaluation of vascular reactivity. Results: Wistar females exposed
to Cd had a reduction in weight gain and systolic blood pressure did not change
significantly after exposure to the metal. No difference was found in estrogen
dosage between control and cadmium-exposed rats. In the analysis of
myeloperoxidase (MPO) an increase in the activity of this enzyme was found in
both groups exposed to the metal. Exposure to cadmium produced a
concentration of the metal in the blood of 2.89 μg/L against 0.27 μg/L found in
unexposed females, in males an increase in the concentration of the metal was
observed in relation to females, exposed males had 4, 7 μg/L and unexposed 0.3
μg/L. There was no change in the vascular response to Phenylephrine (Fe),
Acetylcholine (ACh) and Sodium Nitroprusside (NPS) in females, however males
had changes in ACh and Fe curves. Incubation with L-NAME shifted the
concentration-response curve to Fe in both groups, but this effect was smaller in
males exposed to Cd, suggesting reduced nitric oxide bioavailability. In addition,
incubation with apocynin and catalase reduced the response to Fe in males
exposed to Cd, suggesting the release of superoxide anion and hydrogen
peroxide, respectively. Conclusion: The results of the present study demonstrate
that exposure for 30 days to Cd produces an increase in blood pressure and
vascular changes in males, but not in females, suggesting that the cardiovascular
abnormalities induced by the metal are sex-dependent.
