The Effect of Chronic Spinal Cord Injury on Ultrastructure of Epididymal Sperm in Rat

Purpose: The effects of chronic SCI on ultrastructure of spermatozoa aspirated from epididymis of rats. Materials and Methods: 45 adults Wistar rats were divided into 3 groups of SCI, control and sham. Following laminectomy, SCI was induced with a 15g weight dropped from a distance of 10 cm, onto exposed dura matter at T10 level. Sham group underwent laminectomy of T10 only, while control was not exposed to any types of injury or medication. The epididymal sperms were aspirated after 8 weeks in each groups for transmission electron microscopy (TEM) preparation. After primary and secondary fixations, dehydration and embedding, and ultrathin sections were collected on grids and stained by uranyl acetate and lead citrate, the samples were examined with TEM. Results: In electron microscopic study, no ultrastructural changes were observed in sham or control groups. In SCI animals, the majority of spermatozoa showed several alternations such as swollen area, rupture and lysis of plasmalemma, disintegration of acrosomal membranes, persistence of numerous cytoplasmic droplets, mitochondrial swelling, absence of axonemal microtubules, complete degeneration of axoneme, deletion of one or more outer dense fibers, absence of tail plasmalemma, reduction of nuclear electron density, irregularities in tail architecture, formation of apoptotic vacuels and necrotic changes in heads and tails in their ultrastructures.Conclusion: Our electron microscopic study showed that following chronic SCI, several ultrastructure abnormalities developed in epididymal sperms. These changes may impair sperm quality and directly reduce the fertility potentiality after SCI.