New embryo selection method: Zinc ‘fireworks’
It has been previously found in animal studies that zinc is an essential element for the oocyte maturation and activation. In fact, zinc is released in great amounts in oocytes at the moment of fertilisation, a phenomenon termed as the ‘’zinc spark’’. This event was initially observed in mouse oocytes, indicating a crucial role of zinc in fertilisation process.
Now, for the first time, scientists managed to capture this light spark, related to zinc release, emitted this very moment a human sperm cell meets the egg. The zinc release taking place during fertilization, due to sperm binding to the egg, emits light in radiant bursts. The scientists had the chance to watch, from a recorded video, billions of zinc atoms to be released the moment the sperm cell penetrates the egg’s membrane. These zinc ‘’fireworks’’ lasted for about 2 hours after fertilisation.
The most interesting part of the study, as reported by the research team from the University of Northwestern, is that some eggs appear to be brighter than others having a more intense ‘’zinc spark’’. This fact is indicative of their quality and ability to develop into a healthy embryo. According to study results, the percentage of successful embryo selection was more than doubled when correlated to the zinc spark amplitude.
Collectively, this study provided robust evidence that zinc spark is a hallmark of egg activation in mammals, including humans, and therefore could make a clinical tool for predicting which embryos could reach the blastocyst level. The discovery from scientists of Northwestern Medicine could give to fertility clinics a new non-invasive technique for selecting the best egg quality.
So, according to fertility experts the ‘’zinc spark’’ event has the potential to be a new embryo selection method for subfertile couples by increasing the chances of getting pregnant through IVF procedure. Such news give hope to couples struggling with infertility as it is known that about 50% of fertilized eggs through IVF in fertility clinics, fail to develop into a healthy embryo due to genetic abnormalities.