Oral Presentation The Annual Scientific Meeting of the Endocrine Society of Australia and the Society for Reproductive Biology 2014

Low Vitamin D diet and the outcome in male C57Bl/6 mice (#168)

Kuan Minn Cha 1 , Christian Girgis 1 , Rebecca Stokes 1 , Jenny E Gunton 1
  1. Garvan Institute of Medical Research, Darlinghurst, NSW, Australia

BACKGROUND: Vitamin D deficiency is particularly common in winter, when humans tend to gain weight. Vitamin D is also predominantly stored in adipose tissue. Precise effects of vitamin D in adipose tissue are unclear. Low vitamin D due to low diet intake and sun exposure leads to low serum levels of 25-hydroxyvitamin D3 (25D) which is in turn the substrate for formation of the active 1,25-dihydroxyvitamin D3 (1,25D). Adipose tissues express VDR and respond to 1,25D.

AIM: To investigate effects of vitamin D deficiency on the activity of male C57Bl/6 mice, their oxidative metabolism and adipose tissue.

METHODS: C57Bl/6 mice were fed low-D or control diet for 48 weeks. This diet contains increased calcium and phosphorus to prevent low calcium and phosphate in the vitamin D deficient state. Oxymax metabolic cage studies were performed. Subcutaneous, visceral and inguinal fat depots were isolated. Immunohistochemistry and gene expression studies were performed.

RESULTS: Vitamin D deficiency mice had higher vO2 and vCO2 compared to control mice (n=4). These mice also tended to had less visceral fat (0.87±0.10 vs. 1.13±0.11g; p=0.085). In white adipose tissue (WAT), there were 20-fold (p=0.026) and 9-fold (p<0.000001) increases in UCP1 and CIDEA expression which are markers for brown/beige fat. There were also 7-fold (p=0.00075) and 4-fold (p=0.00015) increases in TBX and TMEM26 expression which are associated with beige fat.

CONCLUSION: Vitamin D deficiency induces higher metabolic activity in C57Bl/6 male mice and induces ‘browning’ in WAT. This may be consistent with a physiological response to the vitamin D deficiency which would evolutionarily have been associated with winter and cold exposure.