[Morphological characteristics and phenotypic analysis of multiple morphological abnormalities in sperm flagella]

Objective: To analyze the sperm morphological characteristics of multiple morphological abnormalities of the sperm flagella (MMAF), and to analyze their common features and subtypes. Methods: Twenty-eight patients with abnormal morphology of flagella were analyzed by semen analysis. The morphological characteristics were analyzed by scanning electron microscopy and transmission electron microscopy. Histological observation of one case of testicular tissue was performed. Results: Of the 28 patients, only 13 patients (46.4%) had motile spermatozoa, 12 of which had a sperm motility rate of <10% and a sperm survival rate of 9.0%-80.0%. Under light and scanning electron microscope, sperm with absent, short, coiled, bent and irregular width flagella or their combinations were observed. Transmission electron microscopy showed structural abnormalities of sperm fibrous sheath, mitochondrial sheath. Loss rate of central microtubule was 41.4%-84.6%. The semen of the 2 patients with the absence or presence of the kinetic protein arm and both the inner and lateral motilin arms missing had no motile spermatozoa. There was no statistically significant difference in the proportion of flagellar malformations between the two groups of patients (without motile sperm vs with motile spermatozoa). Conclusion: MMAF is a kind of sperm flagella specific abnormalities. Initially diagnosis can be carried out using light microscopy. Clear diagnosis could be conduct using transmission electron microscopy, and the central microtubule loss of the sperm could be seen as the main feature of the flagella abnormalities. Through the morphological analysis and research, MMAF could be precisely classified, which provide a strong basis for the diagnosis.