Fig 1.
Effect of erythropoietin (EPO) on body weight gain.
(A) Change in body weight. (B) Weekly food intake. (C) Total food intake. (D) Locomotor activity. Values are mean ± SE for 5–10 mice. aP < 0.05 or aaP < 0.01, vs. mice fed normal chow diet (NC-Con). bP < 0.05 or bbP < 0.01, vs. mice fed normal chow diet plus EPO (NC-EPO). cP < 0.05 or ccP < 0.01, vs. mice fed high-fat diet alone (HFD-Con).
Fig 2.
Effect of erythropoietin (EPO) on white adipose tissue (WAT).
Histology of subcutaneous WAT (sWAT) and epididymal WAT (eWAT) were examined by HE staining. (A) Macroscopic images of eWAT in mice fed normal chow diet (NC-Con), mice fed high-fat diet alone (HFD-Con), and mice high-fat diet plus EPO (HFD-EPO). White arrow indicates eWAT. (B) Representative histology of NC-Con, HFD-Con and HFD-EPO mice in sWAT and eWAT. Scale bar = 50 μm. (C) The distribution of adipocyte perimeters in sWAT and eWAT were analyzed for each group.
Table 1.
Metabolic parameters of 8-week-old mice.
Fig 3.
Effect of erythropoietin (EPO) on glucose tolerance and hematocrit levels (Ht).
Four-week-old mice were treated with saline or with EPO (200 U/kg) for four weeks. Intra-peritoneal glucose tolerance tests (IPGTT) (1 g/kg) were performed after overnight fasting. (A) and (B) show blood glucose levels and insulin levels, respectively. (C) shows weekly Ht. Values shown are mean ± SE for 7–10 mice. aP < 0.05 or aaP < 0.01, vs. mice fed normal chow diet (NC-Con). bP < 0.05 or bbP < 0.01, vs. mice fed normal chow diet plus EPO (NC-EPO). cP < 0.05 or ccP < 0.01, vs. mice fed high-fat diet alone (HFD-Con). dP < 0.05 or ddP < 0.01, vs. mice fed high-fat diet plus EPO (HFD-EPO).
Fig 4.
Effect of erythropoietin (EPO) on oxygen consumption and interscapular BAT.
(A) 22-h Oxygen consumption. (B) Oxygen consumption in dark and light phases. (C) Representative infrared thermal images of normal chow diet mice (NC-Con), EPO treated normal chow diet mice (NC-EPO), high-fat diet mice (HFD-Con) and EPO-treated high-fat diet mice (HFD-EPO). (D) Interscapular surface temperature. Values shown are mean ± SE for 8–9 mice. aP < 0.05 or aaP < 0.01, vs. NC-Con. bP < 0.05 or bbP < 0.01, vs. NC-EPO. cP < 0.05 or ccP < 0.01, vs. HFD-Con.
Fig 5.
Effect of erythropoietin (EPO) on differentiation related genes in interscapular BAT (iBAT).
Histology of iBAT was examined by HE staining (Scale bar = 50 μm). (A) Macroscopic images of iBAT. (B) Representative histology of iBAT in normal chow diet mice (NC-Con), high-fat diet mice (HFD-Con), and EPO-treated high-fat diet mice (HFD-EPO). (C) The number of cells/area in iBAT was counted. (D) Real-time PCR experiments. (E) Western blot analysis. Values are mean ± SE for 4–8 mice. aP < 0.05 or aaP < 0.01, vs. NC-Con. bP < 0.05 or bbP < 0.01, vs. mice fed normal chow diet plus EPO (NC-EPO). cP < 0.05 or ccP < 0.01, vs. mice HFD-Con.
Fig 6.
Effect of erythropoietin (EPO) on the expressions of PGC1α and UCP1 in interscapular BAT (iBAT).
(A) Real-time PCR experiments. (B) Western blot analysis. (C) Arbitrary unit multiplied by iBAT weight. Values shown are mean ± SE for 4–8 mice. aP <0 .05 or aaP < 0.01, vs, mice fed normal chow diet (NC-Con). bP < 0.05 or bbP < 0.01, vs. mice fed normal chow diet plus EPO (NC-EPO). cP < 0.05 or ccP < 0.01, vs. mice fed a high-fat diet alone (HFD-Con).
Fig 7.
Effect of erythropoietin (EPO) on EpoR/STAT3 axis in interscapular BAT.
(A) Western blot analysis. (B) pEpoR/EpoR and pSTAT3/STAT3 ratios were calculated. Values given are mean ± SE for 6 mice. aP < 0.05 or aaP < 0.01, vs. mice fed normal chow diet (NC-Con). bP < 0.05 or bbP < 0.01, vs. mice fed normal chow diet plus EPO (NC-EPO). cP < 0.05 or ccP < 0.01, vs. mice fed high-fat diet alone (HFD-Con).
Fig 8.
Effect of erythropoietin (EPO) on the β-adrenergic receptor/Mef2/miR-133 pathway in interscapular BAT.
(A) Real-time PCR experiments. (B) Western blot analysis. (C) Real-time PCR experiments. (D) microRNA analysis experiments. Values given are mean ± SE for 4–8 mice. aP < 0.05 or aaP < 0.01, vs. mice fed normal chow diet (NC-Con). bP < 0.05 or bbP < 0.01, vs. mice fed normal chow diet plus EPO (NC-EPO). cP < 0.05 or ccP < 0.01, vs. mice fed high-fat diet alone (HFD-Con).
Fig 9.
Effect of erythropoietin (EPO) on differentiation-, lipolysis- and thermogenesis-related genes in white adipose tissue (WAT).
(A) Real-time PCR experiments in subcutaneous WAT (sWAT). (B) Real-time PCR experiments in epididymal WAT (eWAT). Values given are mean ± SE for 4–8 mice. aP < 0.05 or aaP < 0.01, vs. mice fed normal chow diet (NC-Con). bP < 0.05 or bbP < 0.01, vs. mice fed normal chow diet plus EPO (NC-EPO). cP < 0.05 or ccP < 0.01, vs. mice fed high-fat diet alone (HFD-Con).
Fig 10.
Effect of erythropoietin (EPO) on expression/secretion of FGF21 in interscapular BAT (iBAT) and the liver and gluconeogenesis-related genes in the liver.
(A) Real-time PCR experiments in iBAT. (B) Western blot analysis. (C) Real-time PCR experiments in liver tissue. (D) Plasma levels of FGF21. (E) Real-time PCR experiments in liver tissue. Values given are mean ± SE for 3–8 mice. aP < 0.05 or aaP < 0.01, vs. mice fed normal chow diet (NC-Con). bP < 0.05 or bbP < 0.01, vs. mice fed normal chow diet plus EPO (NC-EPO). cP < 0.05 or ccP < 0.01, vs. mice fed a high-fat diet alone (HFD-Con).