IL-22 promotes beigeing of white adipose tissue.
6 weeks old male C57BL/6J SPF wild type mice were fed NCD or HFD for 12 weeks and then divided into four groups (NCD-Saline, NCD-IL-22, HFD-Saline, HFD-IL-22). Mice were intraperitoneally injected with 4 µg/kg IL-22 every other day for 6 weeks. The saline group was injected with saline. n=6 mice/group.
A. Oral glucose tolerance test (OGTT) and area under the curve (AUC). n=6 mice/group.
* indicates P<0.05 vs NCD-Saline; # denotes P<0.05 vs HFD-Saline.
B. Rectal temperature of mice during a 6 h cold challenge (4 °C). n=6. * indicates P<0.05 vs NCD-Saline; # denotes P<0.05 vs HFD-Saline.
C. Representative image of sWAT of the four groups, NCD-Saline, NCD-IL-22, HFD-Saline, HFD-IL-22.
D. qPCR analysis of thermogenic genes of sWAT. n=6 mice/group. * indicates P<0.05 vs NCD-Saline; # denotes P<0.05 vs HFD-Saline.
E. Representative images of hematoxylin-and-eosin-stained sections of sWAT and eWAT (n=5 for each group).
F. The distribution and average adipocyte size of sWAT and eWAT were determined by ImageJ.
G. Phase-contrast microscopic images of SVF cells and adipocytes.
H. qPCR analysis of thermogenic genes in SVF cells and beige adipocytes. n=3. # denotes P<0.05 vs Beige.
I. pSTAT3, STAT3, pMAPK, MAPK, GAPDH, UCP1, β-Actin protein expression in the beige adipocytes or beige adipocytes treated with IL-22 detected by Western blotting. GAPDH and β-Actin was used as the loading control.
All data represent the mean ± s.e.m. Statistical significance was determined by one-way ANOVA with Bonferroni’s multiple-comparisons test (A-D, H) or two-tailed Student’s t test (F). sWAT, subcutaneous white adipose tissue; eWAT, epididymal white adipose tissue.