Use of negative staining technique and electron microscopy for the study of structural anomalies of outer dense fibres of human flagellum

Motility disorders due to tail defects are often seen in clinical andrology . Sperm motility should be assessed with regard to the morphology of the fl agellum. Since suitable longitudinal sections are rarely obtained by routin e transmission electron microscopy (TEM) and in view of the importance of d ense fibres in modulating sperm motility and providing tensile strength, a detailed, study of human sperm flagellum by negative staining and TEM was a ttempted. The study was undertaken in two groups of men (I) fertile and (II ) asthenozoospermic. The study revealed that outer dense fibres extend to 5 0-60% of the principal piece. Normal dense fibres were seen in 83% sperms a nd 23% sperms in groups I and LI respectively. The characteristics seen wer e variation in diameter, breakage or degradation with lacking or extended e ndpiece. The negative staining method provides an easy and useful analytica l tool for identifying the defects of dense fibres and quantifying them.