Promising Study Shows Potential Role of NMN in Improving Fertility in Obese Mice
Introduction: Obesity is a growing global health concern that adversely affects reproductive outcomes and maternal health. Maternal obesity is associated with poor reproductive outcomes, including early pregnancy failure and neonatal conditions. Chronic inflammation caused by obesity can impact ovarian physiology and reproductive health. Consequently, obese mice often experience impaired oocyte quality due to mitochondrial dysfunction, meiotic abnormalities, and oxidative stress. Additionally, the adverse effects of maternal obesity on oocytes and preimplantation embryos can lead to long-term metabolic diseases in offspring. Low-quality oocytes are a major contributing factor to the poor reproductive outcomes in obese women.
Background on NMN
Nicotinamide adenine dinucleotide (NAD+) plays a crucial role in various biological processes but decreases with age and metabolic abnormalities. The loss of NAD+ negatively impacts oocyte quality and early embryonic development in obese mice. Nicotinamide mononucleotide (NMN), a precursor of NAD+, has been shown to enhance NAD+ biosynthesis and reverse defects caused by insufficient NAD+ levels. NMN supplementation has already demonstrated benefits in aging mice and type 2 diabetes patients. However, the effect of NMN on oocyte quality and reproductive performance in obese mice has not been thoroughly explored.
Study Design and Results
In this study, researchers established an obesity model by feeding mice a high-fat diet for 12 weeks, resulting in increased body weight and glucose intolerance. The efficacy of NMN supplementation on oocyte quality and reproductive performance in obese mice was investigated. The findings indicated that NMN administration reduced ovarian inflammation, improved oocyte quality, and restored offspring weight in obese female mice. Specifically, NMN improved ovary quality by increasing ovarian weight and elevating the expression levels of genes related to ovarian follicular development. It also effectively decreased inflammation in the ovaries. Moreover, NMN supplementation reversed meiotic defects, DNA damage, and excessive reactive oxygen species (ROS) levels in the oocytes of obese mice. NMN treatment also restored normal spindle-chromosome complex (SCC) structure, which is vital for oocyte maturation and fertilization. Long-term effects of NMN were also observed, as NMN supplementation restored normal birth weight in the offspring of obese mice. This suggests that NMN has the potential to improve reproductive outcomes in obese mice.
The study provides promising evidence of the role of NMN in improving oocyte quality in obese mice, potentially leading to improved reproductive outcomes. The restoration of mitochondrial function, reduction of ROS accumulation, DNA damage, and lipid droplet distribution in oocytes are suggested as potential mechanisms underlying the positive effects of NMN. Further research is needed to validate these findings and explore the potential applications for human fertility.
Title of paper: Administration of nicotinamide mononucleotide improves oocyte quality of obese mice
Author(s): Wang L, Chen Y, Wei J, Guo F, Li L, Han Z, Wang Z, Zhu H, Zhang X, Li Z, Dai X.
Year published: 2022
Published in: Cell Prolif
Original article can be found here.