Environmental Toxins and Their Effects on Male Fertility

Introduction:

Infertility is one of the major concerns in today's world. Almost every one out of six persons suffers from infertility. All over the world, about 48 million couples suffer from infertility. About 15 percent of couples in the reproductive age group suffer from pregnancy-related complications. 30 % of these cases are caused by male infertility. The prevalence of male infertility is increasing day by day. As a result, researchers are trying to identify causative factors that are related to this.

What Is Male Infertility?

Infertility is a condition characterized by the inability of the couple to conceive. When the factors associated with infertility are related to males, it is known as male infertility. Male infertility is related to factors like low sperm count, abnormality in the sperm, and structural problems in the reproductive system. The causative factors for male infertility are:

1. Hormonal Disorders: Hormonal disorders like testosterone and hyperthyroidism are associated with male infertility. Congenital disorders like Kallmann syndrome, Prader-Willi syndrome, and Laurence - Moon - Biedl syndrome are also responsible for male infertility.
2. Genetic Causes: Genetic disorders such as Kallmann syndrome, Klinefelter's syndrome, Young syndrome, Sertoli cell-only syndrome, and Y-chromosomal abnormalities are related to male infertility.
3. Leukocytospermia: Severe infection of the genital tract is responsible for a high number of leukocytes in the semen. Such infections are associated with disorders like chlamydia, herpes, or gonorrhea. Severe autoimmune reactions are also associated with this condition.
4. Urogenital Abnormalities: Congenital, acquired, or structural abnormalities of the urogenital tract can be responsible for male infertility. Conditions like cysts in the ejaculatory tract, ligation of the vas deferens, bilateral orchiectomy (removal of testes), and obstructed epididymis are regarded as causative factors for male infertility.

The male egg is known as sperm. Unlike the female egg, sperm are millions in number. Semen is the seminal body fluid that is secreted by spermatozoa. The quality of semen and the amount of sperm present is the main determining factor for fertilization. That is why the analysis of the semen is necessary. On semen analysis following details are revealed:

1. The normal color of the semen is grayish-white, and the normal value of the semen must be more than 1.5 milliliters. The normal volume is between two to six milliliters after 2 to 7 days of sexual abstinence. If the semen volume is less than 0.5 millimeters, it is called hypospermia.
2. Semen is usually alkaline in nature. The pH is more than 7.2 and ranges between 7.2 to 8.2.
3. The ejaculated semen liquefies within 15 to 20 minutes after ejaculation. Upon ejaculation, the coagulation of semen takes place. Increased liquefaction time signifies a lack of secretion from the prostate. Conditions like ejaculatory duct obstruction or congenital absence of seminal vesicles are responsible for the absence of coagulation.
4. The total number of sperm is important for proper fertilization. Ideally, more than 39 million sperm should be present during ejaculation. Low sperm concentration is known as Oligozoospermia. In such cases, the sperm count is less than 20 million per milliliter. The absence of sperm in the semen is known as azoospermia.
5. The ability of the sperm to move independently is known as sperm motility. In ideal cases, sperm motility is less than 40 percent. The rapid progression of sperm motility should be at least 25 micrometers per second. Problems in the secretion of accessory sex organs responsible for reduced sperm motility.
6. The morphology of the sperm is an important factor for survival and proper functioning of the sperm. If the number of sperm with normal morphology is 14 percent, it is considered ideal for fertilization. The abnormality of sperm morphology can be categorized into head defects, neck and midpiece defects, tail defects, and cytoplasmic droplets. Various types of head defects are small, tapered, pyriform, round, amorphous, vacuolated, and double-head. The neck of the sperm can be bent or asymmetrical. Thick and irregularly shaped midpieces may be linked to infertility. Morphological tail defects are hairpin defects, tail bent, and coiled tails. The presence of cytoplasmic droplets in more than one-third of areas of the sperm head is considered defective sperm.

What Are the Environmental Factors for Male Infertility?

The global increase in male infertility is associated with several environmental factors. These factors are responsible for:

1. Poor quality of semen is produced due to the effect of environmental toxins on the urogenital tract and secretory organs. The qualitative and quantitative characteristic of semen is altered.
2. The production of sperm is affected, and less sperm is produced.
3. The functionality of the semen and sperm is lost due to anatomical alterations.
4. The produced sperm are structurally impaired.

The environmental toxins that are related to infertility are:

1. Endocrine Disrupting Chemicals: These are the toxic chemicals that are responsible for the disruption of hormonal activity. Usually, during puberty, males are exposed to these chemicals. Chemicals present in the powder, talc, deodorant, and plastics are responsible for this. Chemical substances like bisphenol A, diethylstilbestrol, and phthalates. These chemicals act on receptors or secretory glands of various hormones like thyroid, estrogen, and testosterone. As a result, the hormonal level is altered. Also, disruption of gap junction, DNA (deoxyribonucleic acid) methylation, and defective lipid metabolism caused by these chemicals are causative factors for hormonal disruption.
2. Heavy Metals: Heavy metal exposure is one of the commonest causes of male infertility. Metals like cadmium, lead, and arsenic are linked to male infertility. These metals cause testicular dysfunction, poor sperm production, and poor sperm processing. Cadmium used in batteries is responsible for damaging various cells of the reproductive system. Destruction of Sertoli cells causes reduced sperm count and DNA (deoxyribonucleic acid) damage to the sperm. Decreased amount of semen is linked to exposure to lead and mercury.
3. Air Pollution: Air pollution is one of the biggest environmental problems of recent times. Toxic gasses like carbon monoxide, carbon dioxide, nitric oxide, and sulfur dioxide are not only harmful to nature but also to the human body. Exposure to these factors leads to testicular damage, testicular damage, DNA fragmentation of sperm, and chromosomal abnormalities.

Conclusion:

The increasing prevalence of male infertility is a major concern. Male infertility is caused by factors like poor quality of semen production, decreased amount of sperm, and morphological defects of the sperm. Such factors are associated with several environmental toxins. Environmental toxins like heavy metals and toxic gasses are associated with poor-quality sperm and semen production.