If you’re worried that you may have conceived without sex, you can take a test to find out. The test can detect whether sperm has entered the cervix. It can also detect oxygen levels, whether sperm are capacitation on their own, and their movement through the cervix.
Observing sperm’s penetration of the zona pellucida
The mechanism by which sperm penetrate the zona pellucida remains obscure, although indirect observations have been made. The mechanical thrust generated by the sperm flagellum has a role to play, and observing this process is crucial for understanding how sperm reach their target organ.
The zona pellucida is a thick glycoprotein membrane around the oocyte. It acts as a protective barrier between the oocyte and sperm. When sperm reach the oocyte, they release digestive enzymes from their acrosomes and penetrate through the zona pellucida. They then release their haploid nucleus and enter the oocyte. This process is called fertilization.
The zona pellucida is made up of three concentric layers. The fertilized spermatozoon makes a narrow slit in the middle zone of the zona. Extra spermatozoa also enter the zona in similar fashion.
The zona pellucida protects the ovum and embryo. It contributes to the transport of the embryo through the uterine tube and facilitates differentiation of the embryo. Once the embryo enters the uterine cavity, the zona pellucida dissolves over the inner cell mass, revealing the blastocyst.
Observing sperm’s capacitation on their own
Fertilization takes place when a fertilized egg encounters a sperm with enough capacity to pierce the egg’s outer layer, called the zona pellucida. This lining contains chemical attractants that encourage the sperm to travel toward the oocyte. Once sperm make contact with these receptors, a process called capacitation begins, which changes the sperm’s physiological nature to make them extra-motile and ready to fertilize the egg.
Fertilization is a complex process. In order for sperm to reach an egg, they must pass through two layers of the ovary called the zona pellucida and corona radiata. Abnormalities in either of these layers can make this process difficult, and defective interaction between sperm and the egg can result in failure. This may result from an inadequate amount of sperm or insufficient chemoattraction, which can result in incomplete activation of sperm.
One method that helps determine whether a sperm went inside an egg is to monitor the protein that causes them to go into capacitation on their own. Sperm-borne proteins called Swann K induce intracellular calcium release, and are essential for the activation of mouse eggs.
Observing sperm’s reaction to the acrosome reaction
One way of determining if a sperm went inside an egg is to observe the acrosome reaction. For this, you need to wash and sample the sperm cells. Then, you need to permeabilize them and observe them under a wavelength light. If the sperm is bound to the acrosome, it will fluoresce. For this test, you must use at least 200 sperm cells.
This reaction occurs a short time after the sperm fuse with the plasma membrane. During this time, the sperm has to penetrate the female egg cell, but it can be difficult. To overcome this barrier, the sperm undergoes a process called the acrosome reaction. It is caused by a decrease in the internal pH, which causes the outward movement of K + ions.
The present invention offers a reagent for observing the acrosome reaction of a sperm. The kit includes a reagent containing glutaraldehyde, 5 methanol, 2ml ethanol, 0.2g polyvinyl pyrrolidone (PVP), and purified water. The reagent is suitable for carrying out both the clinical and research studies.
Observing sperm’s reaction with the acrosome is another way to confirm whether sperm went inside an egg. NO is a natural hormone produced by the sperm and it triggers the egg to release calcium, which activates the egg’s NOS enzyme and increases the egg’s NO.
Since the Loeb principle was first proposed, evidence has accumulated in favor of the sperm’s ability to activate the oocyte. In 1913, Swann and colleagues injected a sperm cytosolic extract into the oocyte and saw that a persistent Ca+ 2 oscillation occurred. Their indirect evidence was critical in defining SOAF. It is important to remember that SOAF must involve the release of intracellular Ca+ 2 and must be regulated by the PIP3-signaling pathway.
