Title:Chronic Inorganic Nitrate Administration Increases the Expression
of Genes Involved in the Browning of Gonadal Adipose Tissue in
Ovariectomized Rats
Volume: 24
Issue: 7
Author(s): Nasibeh Yousefzadeh, Sajad Jeddi and Asghar Ghasemi*
Affiliation:
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical
Sciences, Tehran, Iran
Keywords:
Nitrate, nitric oxide, female rats, gonadal adipose tissue, browning of WAT, anti-obesity effects.
Abstract:
Background and Objective: Nitrate, as nitric oxide (NO) donor, has been suggested
as a nutrition-based treatment for decreasing the risk of menopause-related obesity. This study
aimed to specify the effects of chronic inorganic nitrate administration on uncoupling protein-1
(UCP-1), peroxisome proliferator-activated-receptor-γ (PPAR-γ) coactivator-1α (PGC-1α), and
PPAR-γ expression in gonadal adipose tissue (GAT) of ovariectomized (OVX) rats.
Methods: Female rats were assigned to 3 groups: Control, OVX, and OVX+nitrate (n=7/group),
which consumed water containing inorganic nitrate (100 mg/L) for 9 months. At month 9, GAT
was used for the measurement of NO metabolites (NOx), mRNA levels of NO synthases (endothelial
(eNOS), inducible (iNOS), neuronal (nNOS)), and mRNA and protein levels of UCP-1,
PGC-1α, and PPAR-γ.
Results: OVX rats had lower NOx concentration (45%) and eNOS (38%) and nNOS (30%) expression
in GAT that was restored to normal values following nitrate administration. OVX rats
had significantly lower mRNA and protein levels of UCP-1 (83% and 30%), PGC-1α (65% and
39%), and PPAR-γ (66% and 34.5%) in GAT. Chronic inorganic nitrate administration in OVXrats
increased mRNA and protein levels of UCP-1 (128% and 34%), PGC-1α (115% and 43%),
and PPAR-γ (236% and 38%), respectively.
Conclusion: In OVX rats, chronic nitrate administration increased gene and protein levels of
UCP-1, PGC-1α, and PPAR-γ in GAT, indicating the anti-obesity effects of nitrate are partially
mediated by the white adipose tissue (WAT) browning. Moreover, the stimulatory effect of inorganic
nitrate on the WAT browning in OVX rats was associated with blunting the OVXinduced
NO deficiency in GAT.