Environmental Enrichment Promotes Antioxidant Effect in the Ventrolateral Medulla and Kidney of Renovascular Hypertensive Rats
Luiz Eduardo Sousa
Iuri Ferrari Del Favero
Frank Silva Bezerra
Ana Beatriz Farias de Souza
Andreia Carvalho Alzamora
Dr. Luiz Eduardo Sousa
Figure 2 – Baseline levels of mean arterial blood pressure (MAP, mmHg) in hypertensive (2K1C) and normotensive rats (Sham) subjected to environmental enrichment (EE) and standard condition (St). Direct measurements of MAP were performed on the 4th weeks after 2K1C surgery. Letters (above the bars) indicate significant differences. (a) The difference in relation to the Sham-St; (b) Difference in relation to the Sham-EE analysed by Kruskal-Wallis test, followed by Dunn’s post-test a (p < 0.05) (n = 7 in each group). Data are expressed as median, minimum and maximum value.
Background: Arterial hypertension is a precursor to the development of heart and renal failure, furthermore is associated with elevated oxidative markers. Environmental enrichment of rodents increases performance in memory tasks, also appears to exert an antioxidant effect in the hippocampus of normotensive rats.
Objectives: Evaluate the effect of environmental enrichment on oxidative stress in the ventrolateral medulla, heart, and kidneys of renovascular hypertensive rats.
Methods: Forty male Fischer rats (6 weeks old) were divided into four groups: normotensive standard condition (Sham‑St), normotensive enriched environment (Sham-EE), hypertensive standard condition (2K1C-St), and hypertensive enriched environment (2K1C-EE). Animals were kept in enriched or standard cages for four weeks after all animals were euthanized. The level of significance was at p < 0.05.
Results: 2K1C-St group presented higher mean arterial pressure (mmHg) 147.0 (122.0; 187.0) compared to Sham-St 101.0 (94.0; 109.0) and Sham-EE 106.0 (90.8; 117.8). Ventrolateral medulla from 2K1C-EE had higher superoxide dismutase (SOD) (49.1 ± 7.9 U/mg ptn) and catalase activity (0.8 ± 0.4 U/mg ptn) compared to SOD (24.1 ± 9.8 U/mg ptn) and catalase activity (0.3 ± 0.1 U/mg ptn) in 2K1C-St. 2K1C-EE presented lower lipid oxidation (0.39 ± 0.06 nmol/mg ptn) than 2K1C-St (0.53 ± 0.22 nmol/mg ptn) in ventrolateral medulla. Furthermore, the kidneys of 2K1C-EE (11.9 ± 2.3 U/mg ptn) animals presented higher superoxide-dismutase activity than those of 2K1C-St animals (9.1 ± 2.3 U/mg ptn).
Conclusion: Environmental enrichment induced an antioxidant effect in the ventrolateral medulla and kidneys that contributes to reducing oxidative damage among hypertensive rats. (Arq Bras Cardiol. 2019; 113(5):905-912)
Keywords: Renovascular Hypertension; Oxidative Stress; Enviromental Enrichment; Ventrolateral Medulla; Kidney.