EPA induces in vivo and in vitro expression of the apelin/APJ system in muscle.

<p>(A) Apelin and (B) APJ mRNA expression in soleus muscle of ND (n = 7), HFD (n = 10) and HFD+EPA (n = 5). Results represent mean ±SEM **p<0.01, ***p<0.001, ns: not significant. (C) Apelin mRNA expression and (D) secretion in differentiated C2C12 cells treated with the indicated EPA concentrations or the corresponding BSA content for 24 hours after 12-hour serum deprivation. Data are mean ±SEM n = 4–5 in each condition. *p<0.05, **p<0.01 ***p<0.001. (E) Effect of 100 µM EPA in the absence or in the presence of the PI3K inhibitor LY294002 (20 µM) or the ERK 1/2 inhibitor U0126 (20 µM) for 24 h after 12-hour serum deprivation on apelin mRNA expression and (F) secretion in differentiated C2C12 cells. Results represent mean ±SEM (n = 4–5 in each condition) *p<0.05, **p<0.01, ns: not significant.</p

Protective effect of EPA supplementation on the HFD-induced impaired glucose metabolism.

<p>(A) Glycemia and (B) insulinemia in 6 h-fasted mice fed a ND (n = 12), a HFD (n = 14) or a HFD+EPA (n = 14) after 10 weeks. Results represent mean ±SEM. ***p<0.001, (C) OGTT curves and area under the curve (AUC) of glycemia monitored during OGTT performed on 6 h fasted (during light period) mice after 9 weeks of diet in ND (n = 4), HFD (n = 6) and HFD+EPA (n = 6) mice. Results represent mean ±SEM. *p<0.05, **p<0.01, ***p<0.001 vs ND; and ## p<0.01, ### p<0.001 vs HFD.</p

Effect of EPA on adipokines and APJ mRNA expression in adipose tissue.

<p>(A) Leptin, (B) Adiponectin, (C) Apelin and (D) APJ expression in total adipose tissue of ND (n = 12), HFD (n = 14) and HFD+EPA mice (n = 14). Results represent mean ±SEM **p<0.01, ***p<0.001</p

Plasma lipid composition.

<p>SFA (Saturated Fatty Acids), MUFAs (Mono-Unsaturated Fatty Acids) and PUFAs (Poly-Unsaturated Fatty Acids) were measured by gas-liquid chromatography in plasma of fasted mice after 10 weeks feeding with ND (black column, n = 6), HFD (white column, n = 12) or HFD+EPA (grey column, n = 9). Data are expressed as mean ±SEM. *p<0.05, **p<0.01, ***p<0.001 vs ND; # p<0.05, ## p<0.01, ### p<0.001 vs HFD. ns: not significant</p

Protective effect of EPA supplementation on the HFD-induced obesity.

<p>(A) Body weight in mice after 10-week feeding with a ND (n = 12), HFD (n = 14) or HFD+EPA(n = 14). Results represent mean ±SEM. *p<0.05, **p<0.01, ***p<0.001 vs ND; and ### p<0.001 vs HFD, ns: not significant. (B) fat and lean mass and (C) fat pads weights of subcutaneous (Subcut), perigonadal (Perigon) and mesenteric (Mes) adipose tissue in mice fed for 10 weeks with a ND or N (n = 12), HFD or H (n = 14) or HFD+EPA or E (n = 14) Results represent mean ±SEM. ***p<0.001, (D) Representative photographs of H&E staining of liver section of mice fed the different diets for 10 weeks (bar = 200 µm).</p

Effect of EPA on muscle lipid metabolism.

<p>(A) Intramuscular triglycerides content in red gastrocnemius of ND (n = 9), HFD (n = 10) and HFD+EPA (n = 10) mice. (B) ¹⁴C-palmitate complete β-oxidation and mRNA expression of (C) CPT1b and (D) UCP3 in soleus muscle of ND (n = 9), HFD (n = 6–10) and HFD+EPA mice (n = 6–10). Results are mean ±SEM and were normalized to the ND group (100%) for B, C and D, *p<0.05, **p<0.01, ***p<0.001</p

Respiratory parameters and oxidative stress in liver mitochondria isolated from rats fed a normal, HL or HFO diet.

<p>Respiratory parameters are expressed in ng atoms oxygen × min⁻¹×mg⁻¹ protein.</p><p>OCR =  oxygen consumption rate.</p><p>Data are means ± SE for 8 rats in each experimental group.</p><p>*P<°.05 compared to N rats, and ^#P<0.05 compared to L rats. N =  rats fed normal low-fat diet; L =  rats fed HL diet; F =  rats fed HFO diet.</p><p>CPT =  carnitine palmitoyl transferase.</p

Composition of diets.

a<p>Purified high-nitrogen casein containing 88% protein.</p>b<p>Fish oil  =  Cod liver Oil.</p>c<p>American Institute of Nutrition (1977).</p>d<p>American Institute of Nutrition (1980).</p

F rat mitochondrial features.

<p>Mitochondrial length and tubular/round ratio. (<b>A</b>), F1–6, F mitochondria exhibited light matrix and numerous cristae parallel with the longitudinal axis (double-arrow). F1: Boomerang-shaped mitochondria, suggesting a previous fusion process. F2–3: Mitochondrial cluster forming a fused network. F3: Long, cup-shaped mitochondrion surrounding a lipid droplet (ld). F4–5: Paracrystalline inclusions (black arrows) in the intracristal space. Donut-shaped formation (interrupted arrow). F6: Autophagosome containing a donut-like mitochondrion with enclosed degraded cytoplasm. (<b>B</b>) and (<b>C</b>), Based on EM images, L rats had the shortest mitochondria and the lowest tubular/round ratio (%). *P<0.05 vs. N. #P<0.05 vs. L rats.</p

Proteins relevant to mitochondrial dynamics.

<p>(<b>A</b>), Immunohistochemical reaction and (<b>B</b>), immunoblot for Mfn2. (<b>C</b>), Immunohistochemical reaction and (<b>D</b>), immunoblot for OPA1. (<b>E</b>), Immunohistochemical reaction and (<b>F</b>), immunoblot for Drp1. (<b>G</b>), Immunoblot for Fis1. (<b>B</b>), (<b>D</b>), (<b>F</b>) and (<b>G</b>), Densitometric analysis data shown as means ± SE. *P<0.05 vs. N rats. #P<0.05 vs. L rats. For all immunoblots, representative blots are shown for each protein of interest. The intensities of the bands were normalised to that of Cox IV.</p