Abstract
Nicotinamide riboside (NR) is a nicotinamide adenine dinucleotide (NAD+) precursor. We previously reported that NR supplementation prevented the development of liver fibrosis in male mice. However, whether NR exerts a similar effect in females is unknown. Therefore, we determined whether NR supplementation can prevent obesity-induced inflammation and fibrosis in the liver and white adipose tissue (WAT) by providing NAD+ in obese female mice. Female C57BL/6J mice at the age of 8 weeks (young) and 16 weeks (old) were fed a high-fat/high-sucrose/high-cholesterol diet (HF) or HF diet supplemented with NR at 400 mg/kg/day for 20 weeks. While NR had minor effects in young female mice, it significantly reduced body weight gain, fat mass, glucose intolerance, and serum cholesterol levels compared to the HF group in old females. Hepatic NAD+ level tended toward an increase in the NR group (P=0.054), but NR did not attenuate serum alanine aminotransferase levels, steatosis, and liver fibrosis in old female mice. However, NR decreased weight and adipocyte size in gonadal WAT (gWAT) of old females. NR also reduced the number of crown-like structures and the expression of inflammatory genes, along with decreases in fibrogenic gene expression and collagen accumulation in gWAT compared with the HF group. Also, old mice fed NR showed increased metabolic rates, physical activity, and energy expenditure compared with the HF. Thus, our results indicated that NR supplementation exerted an anti-obesity effect and prevented the development of inflammation and fibrosis in the WAT of old, but not young, female mice with diet-induced obesity.
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