Chronic nitrate administration increases the expression the genes involved in the browning of white adipose tissue in female rats

Abstract

Nitrate, a nitric oxide (NO) donor, has antiobesity effect in female rats. This study hypothesized that the antiobesity effect of nitrate in female rats is due to the browning of white adipose tissue (WAT). Female Wistar rats (aged 8 months) were divided into two groups (n = 10/group): the control group received tap water and the nitrate group received water containing 100 mg/L of sodium nitrate for 9 months. At months 0, 3, 6, and 9, obesity indices were measured. At month 9, gonadal adipose tissue was used to measure messenger RNA (mRNA) and protein levels of peroxisome proliferator‐activated receptor‐γ (PPAR‐γ), PPAR‐γ coactivator 1‐α (PGC1‐α), uncoupling protein 1 (UCP1), and adipocyte density and area. After the 9‐month intervention, nitrate‐treated rats had lower body weight, body mass index, thoracic circumference, and abdominal circumference by 6.4% (p = .012), 9.1% (p = .029), 6.0% (p = .056), and 5.7% (p = .098), respectively. In addition, nitrate‐treated rats had higher PPAR‐γ (mRNA: 1.78‐fold, p = .016 and protein: 19%, p = .076), PGC1‐α (mRNA: 1.69‐fold, p = .012 and protein: 68%, p = .001), and UCP1 (mRNA: 2.50‐fold, p = .001 and protein: 81%, p = .001) in gonadal adipose tissue. Nitrate also reduced adipocyte area by 35% (p = .054) and increased adipocyte density by 31% (p = .086). In conclusion, antiobesity effect of nitrate in female rats is associated with increased browning of gonadal adipose tissue as indicated by higher expression of PPAR‐γ, PGC1‐α, and UCP1 and reduced adipocyte area and increased adipocyte density.

Long-term inorganic nitrate administration protects against myocardial ischemia-reperfusion injury in female rats

“…The BW-lowering effect of nitrate in current work was not linked to food intake, as food intake was unaffected by the nitrate intervention. It has been reported that nitrate is converted to nitrite and then to NO, decreasing BW by increasing cyclic guanosine monophosphate [ 42 ] and browning of white adipose tissue [ 43 ].…”

Effect of long-term inorganic nitrate administration on myocardial ischemia-reperfusion injury in ovariectomized rats

“…In the current study, in addition to the increase in body weight, serum concentrations of progesterone and estradiol decreased, while those of LH and FSH increased at month 0 (2 months after ovariectomy and before nitrate intervention), confirming the successful establishment of the OVX model ( Yousefzadeh et al, 2020 ). The body weight-lowering effect of nitrate in OVX rats is attributed to its ability to mitigate OVX-induced adiposity ( Yousefzadeh et al, 2022c ), as evidenced by reduced adipocyte size and increased levels of brown adipose tissue ( Yousefzadeh et al, 2022c ; Yousefzadeh and Jeddi, 2022 ).…”