Raspberry Consumption Increases Cardiac NRF2 Transcriptional Products in Angiotensin II-Infused Rats
Abstract Objectives To determine whether raspberry consumption mitigates cardiac oxidative stress induced by angiotensin (Ang) II in rats. Methods Eight-week-old male Sprague-Dawley rats were fed AIN-93M (4% corn oil) diets with or without a 10% w/w raspberry freeze-dried powder for seven weeks. At week 4, rats were implanted with subcutaneous osmotic minipumps that delivered 0.9% saline (control) or Ang II (270 ng/kg body weight/day). At week 7, hearts were excised for protein analysis via western blot. Protein expression of NRF2 and its transcriptional products, HO-1 and NQO1, were quantified in the left ventricle. Data are normalized to control and presented as mean ± standard deviation. Results were analyzed with one-way ANOVA followed by Tukey post hoc test if data were normally distributed. Otherwise, non-parametric Kruskal-Wallis test was conducted. Results The expression of the antioxidant transcription factor NRF2 was significantly increased by raspberry consumption compared with Ang II alone (2.41 ± 0.62, n = 5 vs 1.31 ± 0.20-fold, n = 5, P = 0.002) and compared to control (1.00 ± 0.19-fold, n = 5, P = 0.0003). Additionally, the expression of NRF2 transcriptional product NQO1 was significantly increased by raspberry consumption compared to control (1.70 ± 0.52, n = 5 vs 1.00 ± 0.41-fold, n = 5, P = 0.05) but not compared to Ang II (1.30 ± 0.25-fold, n = 5, P = 0.3). Lastly, HO-1 was significantly increased in rats consuming raspberries compared to control (3.04 ± 1.80, n = 5 vs 1.00 ± 0.23-fold, n = 5, P = 0.02), but not compared to Ang II alone (1.92 ± 1.06-fold, n = 5, P = 0.8). Conclusions Raspberries directly increase NRF2 and its transcriptional products in the hearts of rats infused with Ang II. These findings may translate to cardio-protection from neurohumoral insult due to reduced oxidative stress and increased endogenous antioxidant enzyme activity. Funding Sources This work was supported by the Agriculture and Food Research Initiative (grant no. 2019–67,017-29,257/project accession no. 1,018,642) from the USDA National Institute of Food and Agriculture.