Mixed short-chain fatty acids and high-fiber diet reshape SCFA profiles and attenuate post-infarction cardiac fibrosis in mice

Figures

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  Figure 1. Study design and targeted SCFA profiling in serum and heart tissue. (A) Group allocation: Control (G0), Sham (G1), MI (G2), MI + mixed SCFAs gavage (G3), and MI + high-fiber diet (HFF; G4). n = 5 per group per time point. (B) Experimental timeline. MI or sham surgery was performed on day 0; mixed SCFAs were administered by oral gavage from day 1 to day 28. Samples were collected at day 7 (interim) and day 28 (final). (C,D) Stacked bar plots showing the relative abundance of individual SCFAs in serum (C) and heart tissue (D) (E,F) PCA score plots based on the targeted SCFA panel for serum (E) and heart tissue (F) (G,H) Unsupervised hierarchical clustering heatmaps of SCFA profiles in serum (G) and heart tissue (H) Panels C–H were used for descriptive and exploratory visualization; no inferential statistical test was applied to these panels.

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  Figure 2. Mixed SCFAs and HFF attenuate post-MI cardiac fibrosis. (A) Representative Masson trichrome staining of cardiac sections at day 28 (collagen in blue) across groups (G0–G4). (B–D) Quantification of immunohistochemistry positive area ratios for Collagen I (B), Collagen III (C), and α-SMA (D) (E–G) Cardiac mRNA expression of Col1a1 (E), Col3a1 (F), and AMPK (G) at day 7. (H–J) Cardiac mRNA expression of Col1a1 (H), Col3a1 (I), and AMPK (J) at day 28. Data are shown as mean ± SD; error bars represent SD. Unless otherwise indicated, n = 5 biological replicates per group per time point. Statistical comparisons among groups were performed using one-way ANOVA followed by Tukey's multiple-comparisons test. Statistical significance is indicated in the panels.

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  Figure 3. Interventions improve myocardial energy status after MI. (A,B) Myocardial ATP content at day 7 (A) and day 28 (B) (C,D) Myocardial NAD⁺/NADH ratio at day 7 (C) and day 28 (D) Data are shown as mean ± SD; error bars represent SD. n = 5 biological replicates per group per time point. Statistical comparisons among groups were performed using one-way ANOVA followed by Tukey's multiple-comparisons test. Statistical significance is indicated in the panels.

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  Figure 4. Circulating biomarkers, cardiac transcriptional changes, and SCFA feature importance after MI. (A–D) ELISA measurements of TGF-β1 (serum; A), cTnT (serum; B), BNP (heart tissue homogenate; C), and BNP (serum; D). (E–H) Cardiac mRNA expression of TGF-β1 (E), Smad2 (F), Smad3 (G), and IL-6 (H) at day 7. (I–L) Cardiac mRNA expression of TGF-β1 (I), Smad2 (J), Smad3 (K), and IL-6 (L) at day 28. (M,N) Random forest feature-importance analysis using Mean Decrease Accuracy for targeted SCFAs in serum (M) and heart tissue (N) Data are shown as mean ± SD; error bars represent SD. Unless otherwise indicated, n = 5 biological replicates per group per time point. For quantitative comparisons in panels A–L, statistical comparisons among groups were performed using one-way ANOVA followed by Tukey's multiple-comparisons test. Panels M,N show random forest feature-importance rankings and were not subjected to inferential statistical testing. Statistical significance is indicated in the panels.