3. Morphology of the normal spermatozoon

The analysis of spermatozoa morphology includes the assessment of head, neck, midpiece and tail. The analysis of the head includes the assessment of head shape and size, nucleus shape and size, acrosomal area (acrosomal index) and acrosomal vacuoles. The shape, size and cytoplasmic droplets are analyzed in the midpiece, principal and terminal pieces of tail (Table 1).

The acrosomal vacuoles are concentrated between the inner and outer acrosomal membranes. They present the migration of acrosin to the spermatozoon surface and may be the earliest event characterizing the beginning of the acrosome reaction. The presence of these vacuoles is considered as a significant marker of successful fertilization of oocytes in vitro [37, 38].

also significantly longer in X chromosome-bearing spermatozoa. A difference of volume of X- and Y-bearing spermatozoa heads is associated with the difference of DNA content (3.5–4%) [40].

Table 2. The comparison of sperm head morphometry for the three staining techniques and spermatozoa of fresh semen

Length (μm) 4.28 0.27a 5.17 0.27b 4.73 0.27c 4.79 0.26 Width (μm) 2.65 0.19a 3.12 0.21b 2.75 0.24a 2.82 0.23

) 9.26 0.99a 12.87 1.19b 10.47 1.21c —

Ellipticity 1.63 0.11 1.68 0.10 1.75 0.13 1.73 0.12 Width/length ratio 0.62 0.04 0.60 0.04 0.58 0.04 0.59 0.04 Elongation 0.23 0.03 0.25 0.03 0.27 0.03 0.26 0.03

Perimeter (μm) 11.83 0.69a 14.33 0.75b 12.99 0.80c —

Roughness 0.83 0.02 0.79 0.02 0.78 0.03 — Regularity 0.96 0.01 0.98 0.01 0.97 0.02 — Acrosome coverage (%) 32.76 7.43 23.73 7.97 46.29 8.63 —

Papanicolaou Rapidiff® SpermBlue® Fresh

Assessment of Human Sperm Cells Morphological Parameters

http://dx.doi.org/10.5772/intechopen.71413

55

Therefore, the morphometric parameters of normal spermatozoon can differ according to staining method of sperm smear [11, 41]. Maree with co-authors [42] maintained that fixatives and stains can change the size of spermatozoa. They reported that morphometric parameters of SpermBlue® stained spermatozoa head differed least from parameters of fresh non-stained

The live morphologically normal spermatozoa can be selected by sperm head birefringence for ICSI. Two types of head birefringence are ascertained on the basis of acrosome integrity: (1) partial head birefringence in acrosome-reacted spermatozoa and (2) total head birefringence in acrosome-non-reacted spermatozoa. Using acrosome-reacted spermatozoa shows better ICSI results [28–30]. Spermatozoa with partial head birefringence can present lower ratio of DNA fragmentation and higher ratio of normal nucleus [29]. In other hand, spermatozoa with nuclear vacuoles and DNA fragmentation can show the normal head birefringence. And otherwise, some spermatozoa with normal MSOME morphology and without DNA fragmentation can show no birefringence. Therefore the scientists recommend combining MSOME with evaluation of the head birefringence. It was determined that the lowest amount of DNA fragmentation occurs in sperm selected by MSOME and birefringence, compared to sperm

The abnormalities in morphology of spermatozoa have a negative effect on the outcome of IVF and ICSI. Morphologically abnormal spermatozoa analyzed by light microscopy or MSOME are categorized into subgroups according to the defects of the head, neck, midpiece

spermatozoa (Table 2). Also the results can differ according the technician [17].

selected via just one of the two methods alone [43].

and/or tail.

Area (μm2

(mean SD) [42].

4. Morphological abnormalities of spermatozoa

Normal human spermatozoa carry the X or the Y chromosome. Measuring the spermatozoa sorted by the polymerase chain reaction (PCR) sexing, Cui [39] estimated that the X chromosome-bearing spermatozoa have significantly greater head length, neck and tail length, head perimeter and head area than Y chromosome-bearing spermatozoa. The neck and tail were


Table 1. Features of morphologically normal spermatozoon.


2.1.3. Polarized light microscopy

54 Spermatozoa - Facts and Perspectives

An estimation of head birefringence by polarized light using polarized microscope method is used for analysis of live spermatozoa morphological quality. This birefringence is associated with sub-acrosomal protein filaments and nucleoprotein filaments (Figure 2). The presence of

The analysis of spermatozoa morphology includes the assessment of head, neck, midpiece and tail. The analysis of the head includes the assessment of head shape and size, nucleus shape and size, acrosomal area (acrosomal index) and acrosomal vacuoles. The shape, size and cytoplasmic

The acrosomal vacuoles are concentrated between the inner and outer acrosomal membranes. They present the migration of acrosin to the spermatozoon surface and may be the earliest event characterizing the beginning of the acrosome reaction. The presence of these vacuoles is

Normal human spermatozoa carry the X or the Y chromosome. Measuring the spermatozoa sorted by the polymerase chain reaction (PCR) sexing, Cui [39] estimated that the X chromosome-bearing spermatozoa have significantly greater head length, neck and tail length, head perimeter and head area than Y chromosome-bearing spermatozoa. The neck and tail were

Features References

Nucleus shape Smooth, symmetric and oval [1, 32, 33]

No cytoplasmic droplets and/or disorders or less than half

Shape Straight, uniform, and thinner than the midpiece, uncoiled [34–36]

Size Length 4–5 μm, width 2.5–3.5 μm, length-width ratio 1.5–1.75

birefringence in the head indicates the good morphology of a spermatozoon [26–31].

droplets are analyzed in the midpiece, principal and terminal pieces of tail (Table 1).

considered as a significant marker of successful fertilization of oocytes in vitro [37, 38].

Head Shape Oval [4]

Nucleus size Length 4.75 0.28 μm, width 3.28 0.20 μm

Neck No abaxial implantation [18] Midpiece of tail Shape Slender [1, 32–34]

> Size Length 7–8 μm, width < 1 μm Attachment Axially attached to the head

Mitochondria Not fragmented or damaged

size of normal head

Size Length 45–50 μm, tail/head length ratio 10.3 0.2

Cytoplasmic droplets

Table 1. Features of morphologically normal spermatozoon.

Principal and terminal pieces of tail

Nuclear inside No regional nuclear disorders, ≤ 1vacuole that occupies less than 4% of the nuclear area

Acrosomal size 40–70% of total head area

3. Morphology of the normal spermatozoon

Table 2. The comparison of sperm head morphometry for the three staining techniques and spermatozoa of fresh semen (mean SD) [42].

also significantly longer in X chromosome-bearing spermatozoa. A difference of volume of X- and Y-bearing spermatozoa heads is associated with the difference of DNA content (3.5–4%) [40].

Therefore, the morphometric parameters of normal spermatozoon can differ according to staining method of sperm smear [11, 41]. Maree with co-authors [42] maintained that fixatives and stains can change the size of spermatozoa. They reported that morphometric parameters of SpermBlue® stained spermatozoa head differed least from parameters of fresh non-stained spermatozoa (Table 2). Also the results can differ according the technician [17].

The live morphologically normal spermatozoa can be selected by sperm head birefringence for ICSI. Two types of head birefringence are ascertained on the basis of acrosome integrity: (1) partial head birefringence in acrosome-reacted spermatozoa and (2) total head birefringence in acrosome-non-reacted spermatozoa. Using acrosome-reacted spermatozoa shows better ICSI results [28–30]. Spermatozoa with partial head birefringence can present lower ratio of DNA fragmentation and higher ratio of normal nucleus [29]. In other hand, spermatozoa with nuclear vacuoles and DNA fragmentation can show the normal head birefringence. And otherwise, some spermatozoa with normal MSOME morphology and without DNA fragmentation can show no birefringence. Therefore the scientists recommend combining MSOME with evaluation of the head birefringence. It was determined that the lowest amount of DNA fragmentation occurs in sperm selected by MSOME and birefringence, compared to sperm selected via just one of the two methods alone [43].
