Spermidine, a miracle molecule for boosting the oocytes of aging mice

2023-11-09 07:00:31
A stained semi-thin section of a mouse ovary showing a maturing Graafian follicle. WALKER MI/SCIENCE PHOTO LIBRARY

How can we improve the quality and quantity of oocytes, which decrease with age, which complicates natural or medically assisted procreation? Researchers at Nanjing Agricultural University (China) compared samples of ovarian tissue from young and middle-aged mice, and found that the ovaries of older ones contained significantly less spermidine. They wanted to test the hypothesis according to which this molecule would be a key factor in fertility.

Older mice have poorer quality oocytes and deficient follicles (a type of small sac located in the ovaries in which the oocytes develop). The researchers then injected some of the aging mice with spermidine and compared their eggs to those of control mice. “The oocytes of mice “boosted” by spermidine developed more quickly and presented fewer defects than those of untreated aged mice”they write in their study, including the results were published in Nature AgingOctober 16.

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Spermidine is a molecule (a polyamine) which is found both in the human body and in many animals and plants. Whole grain products (bulgur, quinoa, brown rice, etc.), vegetables and legumes are among the food groups with the highest spermidine content.

First isolated from sperm, spermidine is known to have functions in many cell types – it extends the lifespan of yeast, flies, worms and human immune cells. An increase in dietary spermidine intake has also been associated with a reduction in age-related problems in laboratory animals, including cardiovascular diseases in mice. But until now, its effects on oocyte aging had not been demonstrated.

Effects on follicles and blastocysts

In his study, Bo Xiong, reproductive biologist, shows that mice given a spermidine supplement had more follicles, suggesting that this molecule slows down aging. Spermidine also had an effect on blastocysts – the early stage of human embryo development between the fifth and seventh day after fertilization. Result: the impact on reproduction was immediate, the aging mice – which reproduced naturally – had approximately twice as many pups per litter than the control mice.

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