3.7. Sperm Penetration Assay (SPA)
The purpose of SPA is the measurement of the functional properties of sperm. The assay is based on the removal of the zona pellucida of hamster ova, the species specificity of fertilization and the block to polyspermy. Heterologous penetrations between hamster ova and sperm from a variety of species, containing humans are available. Human ova are recommended for this assay, but they are it is not always present. Besides, there are ethical problems connected with their use. Moreover, hamster ova can be used for the measurement of human sperm function.
For fertilization that happens in vivo the sperm can be applied and have had the acrosome reaction. The physiology of sperm ability is not clear. It is unclear to find out whether capacitated sperm with the ability to penetrate human ova have passed through the acrosome reaction, or whether it happens as an ordinary event during gamete fusion.
The purpose of SPA is to measure potential fertility. SPA is based on the theory that fertile sperm samples will have an ability to penetrate most hamster ova or result in a large quantity of the penetrated ova’s polyspermy. There is an expectation that infertile sperm samples have an ability to penetrate a lower percentage of ova or lead to a lesser degree of polyspermy.
The SPA is recommended for couples whose infertility is unexplained or for couples to define the intrauterine insemination (IUI) or IVF, because SPA results may be unsuccessful with IVF and have lower pregnancy rates in couples that use conception through intercourse.
3.8. Reactive Oxygen Species (ROS) Assay
It is an interesting fact concerning cells that live under aerobic conditions and take into consideration oxygen. Oxygen is necessary for survival and normal function; there is a possibility of its potentially toxic metabolites due to the generation of oxygen-free radicals. Some of these metabolites, known under the name ROS, is produced by spermatozoa and produces toxic effects on sperm function. Produced at the right time and quantity, these ROS can be initiators and promoters of normal physiologic reactions known as sperm hyperactivation and capacitation. In human semen, 40% of semen samples from a population of men, that had an infertility problem and that were not chosen, high ROS formation was found.
4. Genetic Evaluation
Genetic abnormalities that are connected with male infertility are the results of male infertility and the offspring may suffer from it too. During a genetic evaluation a diagnosis should be put, the genetic origin of the abnormality should be found out, then the pattern of inheritance should be defined and information concerning its history, variation, and expression should be given. Abnormalities found in the offspring by a doctor can be inherited from his parents or they can be a result of some other factors. The three most widespread genetic factors that are connected with male infertility are cystic fibrosis (CF) gene mutations that can cause to congenital absence of the vas deferens, Y-chromosome microdeletions that can cause to spermatogenic impairment, and karyotype abnormalities.
When azoospermia is found at the patient, the urologist should find out whether testicular failure or obstruction is available. If the vas deferens is not evident, unilaterally or bilaterally, then CF gene mutation testing should be conducted. The most widespread encountered condition in this category is cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations, which are found in men who have azoospermia and vasal or epididymal abnormalities. The most common manifestation is congenital bilateral absence of the vas deferens that is found within1%-2% of men who suffer from infertility. The carrier status for this autosomal recessive condition considered to be normal and is available in 1/25 persons who are residents of Northern Europe and those who have over 550 CFTR gene mutations. Due to the potentially fatal character of this autosomal recessive disorder for the offspring, screening may be routine when vasal or epididymal abnormalities can be possible.
Deletions in theY chromosome (i.e., DAZ, YSRRM, and AZF a, b, c deletions) lead to severe oligospermia and azoospermia. That’s why a genetic etiology of male factor infertility may be found in these patients. Patients, who have a sperm density of less than 10 million/mL, are recommended to send peripheral blood for Y chromosome analysis. A positive analysis is effective for diagnosis and in the age of intracytoplasmic sperm injection (ICSI), for potential transmission of subfertility to a male offspring. The purpose of chromosomal analysis (+/- painting) is recommended for patients who have passed ICSI but they are to be conducted in cases of ICSI failure.
Karyotyping can be connected with genetic abnormalities in the infertile male that contain structural chromosomal disorders such as Klinefelter's (classic 47,XXY), mixed gonadal dysgenesis, chromosomal translocations, and XYY syndromes. Chromosomal abnormalities are rare in the general population, found only at 0.5%. Klinefelter's syndrome is available in 1 in 500 live male births and it is considered to be the most widespread abnormality of sexual differentiation due to the occurrence of the XYY male syndrome in about 1 in 1000 live births. Most of these patients are fertile. Infertility is considered being a widespread problem. It is necessary to define these disorders due to the advent of ICSI; men who suffer from Klinefelter's syndrome (mosaic and non-mosaic) can have testis biopsies and be the initiators of a pregnancy that have resultant genetically normal embryos. Men who have Klinefelter's may also suffer from severe oligozoospermia.
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