Rice (Oryza sativa L.) bran preserves cardiac function by modulating pro-inflammatory cytokines and redox state in the myocardium from obese rats

Fig. 1. Nutritional profile. (A) Body weight, (B) body fat, (C) adiposity index, and (D) acid steatocrit of the control diet (C), high-sugar fat diet (HSF), and high-sugar fat diet supplemented with rice bran (HSF + RB) groups. Data expressed as median (min—max). Mean is indicated as + . *p < 0.05. ANOVA followed by Tukey for A, B, C and D

Fig. 2. Plasma metabolic and hormonal analyses. (A) Triglycerides, (B) glucose, (C) insulin, and (D) homeostatic model assessment of insulin resistance (HOMA-IR) index of the control diet (C), high-sugar fat diet (HSF), and high-sugar fat diet supplemented with rice bran (HSF + RB) groups. Data expressed as median (min–max). Mean is indicated as + . *p < 0.05. ANOVA followed by Tukey for A, C and D; Kruskal–Wallis followed by Dunn’s for B

Fig. 3. Pro-inflammatory cytokines in cardiac tissue. (A) Interleukin-6 (IL-6) and (B) tumoral necrosis factor alpha (TNF-α) levels of the control diet (C), high-sugar fat diet (HSF), and high-sugar fat diet supplemented with rice bran (HSF + RB) groups. Data expressed as median (min–max). Mean is indicated as + . *p < 0.05. ANOVA followed by Tukey for B; Kruskal–Wallis followed by Dunn’s for A

Fig. 4. Antioxidant enzyme activities and oxidative markers in cardiac tissue. (A) Superoxide dismutase (SOD), (B) catalase (CAT), and (C) glutathione peroxidase (GPx) activities and (D) protein carbonylation (CBO) and (E) malondialdehyde (MDA) levels of the control diet (C), high-sugar fat diet (HSF), and high-sugar fat diet supplemented with rice bran (HSF + RB) groups. Data expressed as median (min–max). Mean is indicated as + . *p < 0.05. ANOVA followed by Tukey for A, B, C and D; Kruskal–Wallis followed by Dunn’s for E

Fig. 5. Correlation among structural and functional cardiac data and nutritional, metabolic, hormonal, inflammatory, and oxidative profiles visualized by a heatmap. LA left atrium diameter; AO aorta diameter; LVDD left ventricle (LV) diastolic diameter; RWT LV relative wall thickness; EF ejection fraction; PWSV posterior wall shortening velocity; S’ tissue Doppler imaging (TDI) of mitral annulus systolic velocity; EDT E wave deceleration time; E early diastolic mitral inflow velocity; E’ TDI of early mitral annulus diastolic velocity; A’ TDI of late mitral annulus diastolic velocity; BW body weight; BF body fat; AI adiposity index; AS acid steatocrit; TG triglycerides; IL-6 interleukin-6; TNF-α tumoral necrosis factor alpha; SOD superoxide dismutase; CAT catalase and MDA malondialdehyde. Data of all experimental groups were gathered and analyzed by GraphPad Prism 8 software using a 2-tailed Pearson’s correlation test. As shown by the color scale, the blue color indicates a negative correlation, while the red color indicates a positive correlation. The symbol * indicates a statistically significant correlation (p < 0.05)

Fig. 6. (A) Unsupervised multivariate principal component analysis (PCA) plot showing the multivariate variation among control, high-sugar fat (HSF), and high-sugar fat supplemented with rice bran (HSF + RB) diets in relation to all evaluated parameters. Each data point represents a sample, which is colored by the annotation of its diet type. (B) Hierarchical clustering analyses (Heatmap) using unsupervised Euclidean distance summarizes the effect of rice bran (RB) on the studied parameters of rats fed on a high-sugar fat diet (HSF). All evaluated parameters abbreviations are as defined in Fig. 5

Fig. 7. Overview of the changes induced by HSF diet (red arrows) and preventive effect of RB supplementation (green arrows). The HSF intake increases body weight and adiposity (obesity), leads to metabolic changes, cardiac dysfunction, increase of IL-6 and TNF-α levels in cardiac tissue and redox imbalance. The RB supplementation was able to prevent the metabolic changes, cardiac dysfunction, increase of cytokines and redox imbalance in cardiac tissue. HSF high-sugar fat diet, RB rice bran, IL-6 interleukin-6; TNF-α tumoral necrosis factor; SOD superoxide dismutase; CAT catalase and MDA malondialdehyde