Sperm motility and morphology as changing parameters linked to sperm count variations.AA Dua, SR Vaidya
Dept. of Physiology, Grant Medical College, Byculla, Mumbai, Maharashtra.
Variations in semen analyses of 177 males over a 1 year period were assessed. The average means of total counts, motility, morphology, total motile count and non-motile % were determined for 5 classes of patients ranging from azoospermic to normospermic. Positive relationships between a falling sperm count, a decrease in motility and total motile counts were seen. Also, increasingly, abnormal forms were found with lower sperm counts.
Keywords: Adolescent, Adult, Human, Male, Middle Age, Oligospermia, classification,diagnosis,Reproducibility of Results, Severity of Illness Index, Sperm Count, methods,Sperm Motility, physiology,Spermatozoa, abnormalities,cytology,
Semen analysis remains the single most useful and fundamental investigation in the search for the cause of infertility.. Considerable information can be obtained on semen analysis. Data available over the past 20 years reveal that in 1/3 rd of the cases of infertility, significant pathology is found in the male partner and in 20% cases, in both partners. Thus, in roughly 50% of the cases, the male factor is at least partially responsible for infertility,.
On the basis of the total semen score given to the parameters like morphology, motility, the sample may be classified as fertile, sub-fertile or infertile. Interpretation of results depends on the method of collection and analysis as well as definition of normality. Recent in-vitro studies have demonstrated that 1 million - 6 million sperms may be adequate for penetration of the human egg 4, indicating low counts and infertility do not have a linear relationship.
The present study addressed three questions viz. What variations exist in the motility of sperms? Does motility vary with the count? Does variation in count affect morphology of sperms?
Over a year, 177 semen analyses were performed Majority of subjects were referrals from Obstetrics /Gynaecology and Surgery departments. Prior to the date of semen sample collection, the patients were advised abstinence of 4 days. Semen was collected by masturbation in a sterile glass container. Specimens were analysed by a trained technician within 60 minutes of their collection. "Volume" was measured to the nearest millimetre in a calibrated chamber. Sperm counts were measured using a haemocytometer. Both sides of the Neubauer chamber were used and counts were averaged from both sides. Motility was assessed under low power to locate representative areas and then motion was assessed in 10 high-power fields. The quality of motility was evaluated subjectively as excellent, good and sluggish which correspond closely with the range 0-4 suggested by Amelar et al.
The morphology of sperms were observed under the high power of the microscope either unstained or after Leishmann/Eosin + methylene blue staining. Normal cells had small oval heads, slender necks and long tails. Semen parameters included volume (ml), count (million/ml), motility % and morphologic features. Total sperm output was derived by multiplying the count and volume.
All statistics were calculated on the basis of individual data and then averaged over subjects. The average means of various heads like number- of sperms in million/ml, total count (millions), motility % etc, were completed for 5 class types ranging from azoospermic to normospermic.
The age range of patients was 18 to 52 yrs. The patients ranged from azoospermic to normospermic [Table - 1]. These patients were classified into 5 types based on the sperm counts as shown in [Table - 1]. Seventy-one males were found to be normospermic (mean age 25.4 yrs). The rest (106) non-normospermic males had an average age of 28.6 yrs, with intratype averages shown in [Table - 1].
Normospermic males are of a lower average age than non-normospermic males [Table - 1]
Analysis of semen for sperm count (million/ml) and total (based on volume of semen) is depicted in [Table - 2]
Average percentage of motile sperms in all [Table - 5]: Morphological characteristics of sperms (% cases under the different heads are shown in Table normal and abnormal) in 177 semen samples. 3.
A positive relationship is seen between a decreasing sperm count and an increasingly sluggishly motile spermatozoa [Table - 5].
The total motile count and % of non-motile sperms are shown in [Table - 4].
[Table - 5] represents % of normal and abnormal sperms in each category based on their morphological characteristics.
An increase in the abnormal % forms is seen with a decreasing sperm count [Table - 5].
Normal Spermatozoa - had an oval shaped head with regular outline and had no neck (midpiece) or tail defects. The midpiece was less than 1/3rd the width of the head, slender and regular in outline. The tail is slender and uncoiled and with a regular outline. Both the midpiece and tail are aligned along the longitudinal axis of the head. Abnormal forms seen included large oval heads, pyriform heads, tapering heads, round heads and amorphous heads. Sometimes double heads and often only heads were seen. The abnormal midpiece areas showed bent necks or thinned out midpieces. Abnormal tails were either coiled, double or stumpy. A few headless sperms were also noticed.
The total motile count fails as the number of sperms/ml fails. This is an obvious inference from [Table - 6]. The total counts are almost double the number of sperms (millions/ml) in every category. Since Total count = No. of sperms x Volume collected, it is inferred that the average volume of semen collected in normospermic v/s non males in a single ejaculate was equal. What is intriguing is that non-motile % of spermatozoa also increases with a fail in sperm count, thus not favouring sperm production or capacitation. Sperm motility is also not favoured.
Physiological variations in semen parameters to exist and a study by Poland et al  draws our attention to the following facts. Variations occur within healthy men for semen measures, including count, volume, motility and morphological features. It was seen that each day of abstinence increased the volume by an increment of 0.62 ml, the count by 17.6 x 106/ml and motility 1.2%. Sperm count and semen volume correlate well within subjects.
In this study, the normospermic mates are younger than non-normospermic males on an average. Thus vitality decreases with age. As the sperm count fails, the motile % decreases and also, the number of abnormal sperms % rises. Thus a diminishing sperm count increases the chance of abnormality in the semen sample and also decreases the chances of fertilisation not only by quantity of sperms but also by the quality of motility. Recent data suggests that the average sperm count decreases with age.
The causes for pathological variations in sperm count and other semen parameters stems from a disarray in the control mechanisms. Wong et al classified gonadal dysfunction into pre-testicular, testicular and post -testicular causes. Pre-testicular causes are chiefly endocrinal in nature such as hypothalamic tumors, trauma, pituitary defects, hyperprolactinemias, hypothyroidism, congenital adrenal hyperplasia, Cushing's syndrome. Testicular causes such as chromosomal problems; Klinefelter syndrome, XYY syndrome, varicocoele, orchitis, chemical irradiation, aging., idiopathic factors.
Post Testicular causes such as disorders of sperm transport : Mechanical obstruction - congenital, aging infections.; Surgical trauma : Sympathetic denerrvation, ejaculatory disorders, disorders of sperm function.
Semen Parameters and Structure-Function Relationship:
Sperm Count Le number of sperms, directly depends upon the hormonal input from the hypothalamico - pituitary -testis axis and its effect on functional testicular epithelium. This count is affected by Pre-testicular and testicular factors both. If the transit route is blocked, then the count may be low due to post-testicular causes also.
Motility: This comes with sperm maturation in their passage through the epididymis. The process of epididymal sperm maturation occurs under the influence of epididymal proteins and other substances which produce structural and biochemical changes in the sperms. Thus, motility is chiefly a parameter of post testicular i.e. epididymal function.
Morphology: i.e. the differential development of the head, midpiece and tail are functions of the testes as well as the epididymis. Tail motility functions are controlled by mitochondria in the midpiece of the sperm itself.
In conclusion, we state that sperm motility and morphology are changing parameters and their relative levels depend on the existing sperm count in an individual. Physiological variants do exist within subjects and a Structure-function relationship has also been put forth to effectively deal with semen parameter variables.
[Table - 1], [Table - 2], [Table - 3], [Table - 4], [Table - 5], [Table - 6]