Figure 3.

SP reduces RAGE and oxidative stress while increasing nitric oxide in isolated cardiac fibroblasts in response to high glucose. (A) Receptor for advanced glycation end product (RAGE) in cardiac fibroblast lysates; (B) soluble RAGE (sRAGE); and (C) hydrogen peroxide (H₂O₂) in the culture media of isolated cardiac fibroblasts in response to normal glucose (control, 5 mM), high glucose (HG, 25 mM), and HG with increasing concentrations of SP (10 to 1000 nM); (D) superoxide dismutase levels in cardiac fibroblast lysates in response to control, HG, and HG with increasing concentrations of SP; (E) total nitrate/nitrite as a marker of nitric oxide (NO) production in the culture media of isolated cardiac fibroblasts in response to control, HG, and HG with increasing concentrations of SP. SP alters cytokine production by isolated cardiac fibroblasts in response to high glucose. (F) TNF-α, (G) CCL2, (H) IL-4, (I) IL-6, and (J) IL-10 levels in isolated cardiac fibroblast cell culture media in response to normal glucose (control, 5 mM), high glucose (HG, 25 mM), and HG with increasing concentrations of SP (10 to 1000 nM). Data are expressed as mean ± SEM and were analyzed by one-way ANOVA with Tukey post hoc test; * p < 0.05 vs. control, ** p < 0.01 vs. control, **** p < 0.0001 vs. control, † p < 0.05 vs. HG, †† p < 0.01 vs. HG, ††† p < 0.001 vs. HG. n = 4–6 for control and n = 5–6 for all other groups.