In a recent study published in BMC Urology, researchers investigated whether obesity can negatively impact male fertility in rats.
The incidence of obesity has sharply increased in recent years, nearly doubling from 1980 to 2008. Obesity is associated with increased risk of other diseases including type 2 diabetes mellitus, cardiovascular disease, cancers, and sleep apnea syndromes.
Recent research has shown that obesity can also negatively impact reproductive function, particularly in females. The effects of obesity on male reproductive capacity, however, have not been thoroughly investigated.
A recent study, published in BMC Urology, investigated the effects of obesity on spermatogenesis. Adult male rats were stratified into the control or obesity groups. The researchers fed the control rats a normal diet and fed the rats in the obesity group a high-fat diet, which is often used to model obesity.
Significant sperm defects and high levels of cell death in the obesity group
Although the study found no significant difference in sperm concentration, rats in the obesity group had sperm that exhibited significantly reduced motility and viability. Examination of the seminiferous tubules (where sperm are created in testes) showed significant structural defects in the rats in the obesity group, compared to controls.
Further examination revealed significantly higher levels of testicular germ cell death in rats that were fed a high-fat diet. The testicular germ cells are a population of cells that continually give rise to mature sperm throughout an adult’s life.
Finally, the authors noted changes in the male reproductive hormone concentrations between the two groups. Collectively, the data suggest that obesity may be associated with changes in the male reproductive system that contributes to impaired fertility.
Effects need to be investigated in humans
In conclusion, the study found that a high-fat diet was associated with significant changes in sperm motility, testicular and germ cell morphology, and reproductive hormone concentrations in male rats.
More comprehensive studies are needed to better understand the molecular mechanisms by which obesity may negatively impact male fertility. Additionally, the effects of male obesity on sperm function, testicular morphology, and fertility still needs to be thoroughly investigated in humans.
Written by Haisam Shah, BSc
Reference: Jia, Y. F., Feng, Q., Ge, Z. Y., Guo, Y., Zhou, F., Zhang, K. S., … & Gu, Y. Q. (2018). Obesity impairs male fertility through long-term effects on spermatogenesis. BMC Urology, 18(1), 42.