Can selenium-enriched spirulina supplementation ameliorate sepsis outcomes in selenium-deficient animals?

Abstract

In intensive care units, sepsis is the first cause of death. In this pathology, inflammation and oxidative status play a crucial role in patient outcomes. Interestingly, 92% of septic patients exhibit low selenium plasma concentrations (a component of antioxidant enzymes). Moreover, Spirulina platensis, a blue-green algae, demonstrated anti-inflammatory effects. In this context, the main purpose of our study was to analyze the effect of a selenium-enriched spirulina after a selenium deficiency on sepsis outcome in rats. Sixty-four rats were fed 12 weeks with a selenium-deficient food. After 8 weeks, rats were supplemented (via drinking water) for 4 weeks with sodium selenite (Se), spirulina (Spi), or selenium-enriched spirulina (SeSp). Sepsis was then induced by cecal ligature and puncture, and survival duration was observed. The plasma selenium concentration was measured by ICPMS. Expression of GPx1 and GPx3 mRNA was measured by RT-PCR. Blood parameters (lactates and HCO₃^- concentrations, pH, PO₂ , and PCO₂ ) were analyzed at 0, 1, and 2 h as well as inflammatory cytokines (IL-6, TNF-α, IL-10). Sodium selenite and SeSP supplementations restored plasma selenium concentration prior to sepsis. The survival duration of SeSP septic rats was significantly lower than that of selenium-supplemented ones. Gpx1 mRNA was increased after a selenium-enriched spirulina supplementation while Gpx3 mRNA levels remained unchanged. Furthermore, sodium selenite prevented sepsis-induced acidosis. Our results show that on a basis of a Se deficiency, selenium-enriched spirulina supplementations significantly worsen sepsis outcome when compared to Se supplementation. Furthermore, Se supplementation but not selenium-enriched spirulina supplementation decreased inflammation and restored acid-base equilibrium after a sepsis induction.

Keywords: GPx; Spirulina; lactates; selenium; sepsis; supplementation.

FIGURE 1

Experimental protocol

FIGURE 2

Effect of selenium‐deficient diet and sodium selenite, spirulina, or selenium‐enriched spirulina supplementations on rat growth. (a) Weight gain (g per day) in selenium‐deficient diet for 8 weeks and supplementations for 4 weeks. (b) Food intake (g per day) in selenium‐deficient diet for 8 weeks and supplementations for 4 weeks. (c) Water intake (ml per day) in selenium‐deficient diet for 8 weeks and supplementations for 4 weeks. (d) Comparison of water intake in week 1 and week 4 of supplementation. D, deficient, non‐supplemented group; Se, selenium‐supplemented group; Spi, spirulin‐supplemented group; SeSP, selenium‐enriched spirulina‐supplemented group. Data are expressed as mean ± SEM (n = 16 for each group). Different letters indicate significant difference between groups (p < 0.05)

FIGURE 3

Plasma selenium concentration after 8 weeks of selenium‐deficient diet and 4 weeks of sodium selenite, spirulina, or selenium‐enriched supplementation. Data are expressed as mean ± SEM (n = 16 for each group). D, deficient, non‐supplemented group; Se, selenium‐supplemented group; Spi, spirulina‐supplemented group; SeSP, selenium‐enriched spirulina‐supplemented group. Different letters indicate significant difference between groups (p < 0.05)

FIGURE 4

Survival duration rate after induction of sepsis or Sham operations. Data are expressed as percentage of T0 animal number (n = 8 for all group and condition except D sham n = 6 and D sepsis n = 7). D, deficient, non‐supplemented group; Se, selenium‐supplemented group; Spi, spirulina‐supplemented group; SeSP, selenium‐enriched spirulina‐supplemented group.*indicates a significant difference with Se Sepsis group (p < 0.05)

FIGURE 5

Plasma Gpx1 mRNA (a) and plasma Gpx3 mRNA (b) levels in D, Se, Spi, and SeSP rats. Data are expressed as mean ± SEM (n = 16 for each group). D, deficient, non‐supplemented group; Se, selenium‐supplemented group; Spi, spirulina‐supplemented group; SeSP, selenium‐enriched spirulina‐supplemented group. Different letters indicate significant difference between groups (p < 0.05)

FIGURE 6

Davenport diagrams showing pH, PCO2, and bicarbonate (HCO3‐) concentrations of sham and septic rats in the D (a), Se (b), Spi (c), and SeSP (d) groups. Lactate concentrations in the D, Se, Spi, and SeSP groups at different time (e). Data are expressed as mean ± SEM. D, deficient, non‐supplemented group; Se, selenium‐supplemented group; Spi, spirulina‐supplemented group; SeSP, selenium‐enriched spirulina‐supplemented group. “*” indicates a significant difference with T0 in same group (p < 0.05). “#” indicates a significant difference with sham at the same time in the same group (p < 0.05). “$” indicates a significant difference with T1 septic in same group. “&” indicates a significant difference (p < 0.05)

FIGURE 7

IL‐6 (pg/ml) plasma concentration (a), TNF‐α (pg/ml) plasma concentration (b), and IL‐10 (pg/ml) plasma concentration (c) in sham and septic rats at T0, T1h, and T2h. Data are expressed as median ± IQR (n = depending on survival rate). “*” indicates a significant difference with T0 in same group (p < 0.05). D, deficient, non‐supplemented group; Se, selenium‐supplemented group; Spi, spirulina‐supplemented group; SeSP, selenium‐enriched spirulina‐supplemented group; IQR, interquartile range. “#” indicates a significant difference with sham at same time in same group (p < 0.05). “$” indicates a significant difference with T1 septic in same group. “&” indicates a significant difference (p < 0.05)