An illustration of human sperm morphology and their functional ability among different group of subfertile males

Abstract

Condensed sperm chromatin is a prerequisite for natural fertilization. Some reports suggested the prevalence of chromatin condensation defects in teratozoospermia cases with head anomalies; conversely, earlier studies exemplified its occurrence in morphologically normal spermatozoa too. The aim of this study was to compare the condensation defects in correlation with head anomalies among different groups of subfertile males and its impact on the rate of fertilization in assisted reproduction procedures. Ultrastructure analysis of spermatozoa through scanning electron microscopy and atomic force microscopy could facilitate an in-depth evaluation of sperm morphology. Nuclear condensation defects (%) in spermatozoa were analyzed in 666 subjects, and its effect on the rate of fertilization was analyzed in 116 IVF and 90 intracytoplasmic sperm injection cases. There was no correlation of condensation defects with head anomalies (%). Student's t-test showed no significant changes in mean values of condensation defects in abnormal semen samples in comparison with the normal group. Condensation defects were observed in normal spermatozoa too, which was negatively associated with the rate of fertilization in IVF (p < 0.01), but intracytoplasmic sperm injection outcome remained unaffected. Ultrastructure study revealed sperm morphological features in height, amplitude, and three-dimensional views in atomic force microscopy images presenting surface topography, roughness property of head, and compact arrangement of mitochondria over axoneme with height profile at nanoscale. In pathological forms, surface roughness and nuclear thickness were marked higher than the normal spermatozoa. Thus, percentage of normal spermatozoa with condensation defects could be a predictive factor for the rate of fertilization in IVF. From diverse shapes of nucleus in AFM imaging, it could be predicted that defective nuclear shaping might be impeding the activity of some proteins/ biological motors, those regulate the proper Golgi spreading over peri-nuclear theca.

Ultra‐structural analysis of human spermatozoa by aperture scanning near‐field optical microscopy

“…Another typical head defect is the thin head defined also as “tapered” characterized by an elongated head and thin insertion neck . The length of the head was found of 9 μm and width of 4 μm, as evaluated in the SNOM topography (Figure A), much longer than the common healthy one.…”

Sperm morphology: What implications on the assisted reproductive outcomes?

“…Therefore, the junction of midpiece nuclear pole to the base of sperm head shapes the neck. The conclusive phase of spermiogenesis results in the creation of sperm tail, finally originating morphologically normal and mature spermatozoa 4,5 . Thus, spermatogenesis hitches could cause sperm production with abnormal forms 6 …”

“…The conclusive phase of spermiogenesis results in the creation of sperm tail, finally originating morphologically normal and mature spermatozoa. 4,5 Thus, spermatogenesis hitches could cause sperm production with abnormal forms. 6 Sperm morphology (SM) proved to be the more suitable predictor of fertilization potential, rather than other seminal parameters, such as motility and concentration.…”

High-throughput spatial sensitive quantitative phase microscopy using low spatial and high temporal coherent illumination

“…The explanation of obtaining interference fringes in such unbalanced optical configuration is provided in the Supplementary Information . Live human sperm cells are always challenging to image in their natural environment because of the following reasons: the mean swimming speed of sperm cells is 20–160 µm/s 31 – 33 and the tail of the sperm is very thin and generates minute optical thickness 34 . According to the World Health Organization (WHO) criteria, tail of the healthy sperm cell should be thinner than the midpiece and almost of uniform thickness over its length of about 45 µm 35 .…”