Light microscopy morphological characteristics of the sperm flagellum may be related to axonemal abnormalities

Abstract

Although electron microscopy provides a detailed analysis of ultrastructural abnormalities, this technique is not available in all laboratories. We sought to determine whether certain characteristics of the flagellum as assessed by light microscopy were related to axonemal abnormalities. Forty-one patients with an absence of outer dynein arms (type I), a lack of a central complex (type III) and an absence of peripheral doublets (type IV) were studied. Sperm morphology was scored according to David's modified classification. Flagella with an irregular thickness were classified as being of normal length, short or broken. There were correlations between missing outer dynein arms and abnormal, short or coiled flagellum. Type III patients showed the highest flagellar defects (a short (P = 0.0027) or an absent flagellum (P = 0.011)). Just over 68% of the irregular flagella were short in Type III patients, whereas this value was only 34.5% in type I and 26.4% in type IV (P = 0.002). There was a negative correlation between misassembly and spermatozoa of irregular flagella (r = -0.79; P = 0.019). It is concluded that light microscopy analysis of flagellum abnormalities may help provide a correct diagnosis, identify sperm abnormalities with fertility potentials and outcomes in assisted reproduction technologies and assess the genetic risk.

Another look at human sperm morphology

“…With the exception of an absent tail, the incidence of principal piece abnormalities was higher in infertile men and TGCT patients than in fertile men. Detailed high-magnification examination, by light microscopy, of flagellar morphology on semen smears obtained and stained according to a rigorous procedure (World Health Organization, 2010) can be used to detect pathological or genetic conditions when a certain category of tail abnormality is present at high frequency by the approach described here (Mitchell et al, 2015), or by the detection of associations of various tail abnormalities at high levels. For example, an abnormal frequency of thick or irregular tails of normal length, as observed by light microscopy, has led to the description of a new type of sliding spermatozoa, characterized by periaxonemal defects at the TEM level (Feneux et al, 1985).…”

“…As a consequence, it has recently been suggested that precise analyses of the number of sperm abnormalities by conventional microscopy would be a useful approach for diagnosis or research purposes (Menkveld, 2013;Mitchell et al, 2015). The WHO5 report (World Health Organization, 2010) has come to a similar conclusion, with its statement that 'categorizing all abnormal forms of spermatozoa may be of diagnostic or research benefit'.…”

Sperm morphology: assessment, pathophysiology, clinical relevance, and state of the art in 2017

“…Thick tails or irregular tails are sometimes associated with periaxonemal abnormalities (Feneux et al ., ). Other authors highlighted correlations between certain tail characteristics evaluated by optical microscopy and axonemal anomalies demonstrated by electron microscopy (Mitchell et al ., ).…”

Assessment of Human Sperm Cells Morphological Parameters

“…The absence of a tail, the short and broken tail may be related to axonemal abnormalities that are only visible with electron microscopy, and an unknown genetic origin of these abnormalities could be hypothesized [64,65]. Coiled tails of spermatozoa can be associated with varicocele and epididymal dysfunction [66,67].…”