Sperm maturation in dogs: sperm profile and enzymatic antioxidant status in ejaculated and epididymal spermatozoa

Abstract

Spermatozoa become more susceptible to the attack of reactive oxygen species during maturation. To avoid oxidative damage, the epididymis must provide the necessary antioxidant protection. The aim of this study was to compare the canine sperm profile and the enzymatic antioxidant status of the ejaculated fractions and samples collected from the different segments of the epididymis (caput, corpus and cauda). Five adult dogs were used, and after 1-3 weeks, subsequently to bilateral orchiectomy and epididymal storage, sperm samples were collected from the different segments of the epididymis. Samples were evaluated for conventional microscopy and computer-assisted motility analysis: sperm plasma membrane permeability and the activity of the antioxidant enzymes catalase, glutathione peroxidase (GPx) and superoxide dismutase (SOD). Samples collected from the caput and corpus showed lower values for most of the motility variables evaluated, indicating different levels of immaturity. Catalase activity was observed only in ejaculated samples. Conversely, GPx activity was higher in the cauda epididymidis. Correlations were found between SOD and GPx and SOD and sperm motility in the epididymal cauda and corpus, highlighting the importance of the enzymes for the protection of spermatozoa during the transit along the epididymis.

Selenium and vitamin E supplementation enhances the antioxidant status of spermatozoa and improves semen quality in male dogs with lowered fertility

“…The antioxidant enzyme glutathione peroxidase represents the link between selenium, sperm quality and fertility (Boitani & Puglisi, ; Flohe, ). GSH‐Px is present in canine spermatozoa and seminal plasma and reduces hydrogen peroxide to water (Angrimani et al., ; Koziorowska‐Gilun & Strzeżek, ; Strzezek, Koziorowska‐Gilun, Kowalowka, & Strzezek, ). Total antioxidant capacity is the measure of the amount of free radicals scavenged by a test solution and is used to evaluate the antioxidant capacity of biological samples (Ghiselli, Serafini, Natella, & Scaccini, ).…”

Morphological description of the male genital organs ofPontoporia blainvillei(Gervais & d’Orbigny, 1844)

“…On the lateral side of each testicle, the presence of epididymis were observed, such as, the presence of head, body and tail, observed previously in cetaceans [15, 25, 26] and in domestic mammals [27, 28]. Moreover, epididymis of P. blainvillei are characterized to be fixed in testis, as in Phocoena phocoena [22].…”

Proteins of the canine seminal plasma

“…2010), some evidence suggests that GPx is present in canine epididymal secretions (BEIGLBOCK et al, 1998), and a greater activity of this enzyme was reported in samples collected from the cauda of the epididymis than in samples collected from the other segments (caput and corpus) and in the three ejaculated fractions. Therefore, this result indicates that the epididymis may be the main source of GPx in canine semen (ANGRIMANI et al, 2014b). The presence of GPx in the three segments of the canine epididymis might suggest that this enzyme plays an important role in the overall process of sperm maturation (ANGRIMANI et al, 2014a).…”

“…CASSANI et al (2005) reported the SOD activity in the three fractions of canine semen and suggested that this enzyme has a protective effect against the oxidative stress in the canine spermatozoa. Subsequently, SOD activity was also demonstrated in the corpus, caput, and cauda of the canine epididymis, with no significant difference in the enzyme concentration among the three ejaculated fractions and the three epididymis segments (ANGRIMANI et al, 2014b). NEAGU et al (2011) studied the relationship between cellular damage caused by freezing and thawing semen and the activity of antioxidant enzymes in the canine SP.…”