Lectin-Binding Characteristics and Capacitation of Canine Epididymal Spermatozoa

Abstract

ABSTRACT. Cross sections of the testes and the caput, corpus and cauda epididymides removed from 12 dogs were stamped on glass slides, and the sperm on the slides were stained with 6 different FITC-lectins (Con A, DBA, PNA, PSA, SBA, and WGA) to examine the characteristics of the surface glycoproteins (GPs) on canine epididymal sperm. The corpus epididymal sperm were washed three times by centrifugation, and their lectin-binding characteristics were investigated. The washed sperm from the corpus and cauda epididymides were incubated for 24 hr, and the fertilizing capacity of the sperm was evaluated by calculating the percentages of actively motile sperm (%MO), hyperactivated sperm (%HA), and acrosome-reacted sperm (%AR), and the number of canine zona-pellucida (ZP)-binding sperm. The testicular sperm did not stain with SBA lectin, but the SBA lectin fluorescence was observed on the surface of the enitire heads of the caput epididymal sperm. Although all of the entire heads or acrosomal regions of the corpus epididymal sperm stained with all 6 FITC-lectins, the heads and acrosomal regions of the cauda epididymal sperm did not stain with DBA or SBA lectins. Washing the sperm from the corpus epididymis resulted in loss of the fluorescence of the FITC-DBA and -SBA lectins. The mean %MO, %HA, %AR, and ZP-binding number of the cauda epididymal sperm after 24 hr of incubation were higher than the values for the corpus epididymal sperm. All of the mean values for the washed sperm from the corpus and cauda epididymides were higher than the values for the unwashed sperm from the corpus and cauda, and with the exception of %AR, the values from the washed sperm from the corpus epididymis were significantly higher (P<0.05, 0.01). The results indicate that DBA-and SBA-lectin-binding GPs on the surface of canine epididymal sperm are associated with the fertilizing capacity and may be decapacitation factors. KEY WORDS: canine, capacitation, epididymis, lectin, sperm.J. Vet. Med. Sci. 64 (7): [543][544][545][546][547][548][549] 2002 It is well-known that the mammalian sperm plasma membrane surface is coated with various glycoproteins (GPs) [8,9,20,21,25]. Although some GPs are already present on the surface of immature sperm in the seminiferous tubules of the testis [18,19], the surface of the sperm becomes covered with a wide variety of GPs secreted by the epididymal epithelium during sperm transit through the epididymis [5,6,17,23]. Sperm surface GPs are thought to induce sperm maturation and fertilizing capacity [10,20] in the epididymal duct, and techniques utilizing fluorescein-isothiocyanate (FITC)-labeled lectins have revealed that the sperm surface GPs are biochemically modified during sperm transit through the epididymis and that there are species-dependent differences in sperm surface GPs [1,5,6,17,20,23]. Some of the GPs on the surface of epididymal sperm have been suspected of acting as decapacitation factors (DFs) [16,21], and while sperm fertilizing capacity is induced by removing DFs from the sperm surface [7,1...

Distribution of Glycoproteins on Feline Testicular Sperm, Epididymal Sperm and Ejaculated Sperm

“…In the present study we investigated the attachment of GPs during the process of sperm maturation from testicular sperm to ejaculated sperm by using the 8 different FITC-lectins that are routinely used in this kind of study [3,4,6,7,9,11]. It can also be expected to identify groups that are in involved in sperm capacitation and DFs in the cat, the same as has been discussed in other animals.…”

“…73(6): 827-829, 2011 Various glycoproteins (GPs) are present in epididymal secretions and secretions from the prostate gland, vesicular glands, and bulbourethral glands of mammals. Spermatozoa are sent from the testis to the efferent duct in an immature state [1,3,4,6,7]. The spermatozoa mature functionally during their transit through the epididymis, and they undergo capacitation and are stored in the cauda epididymis [2,3,5].…”

“…GPs that coat the surface of spermatozoa are acquired or lost and the characteristics of the GPs on the surface of the plasma membrane are changed during their transit through the epididymis [1-3]. There have been many reports on the relationships between sperm maturation, sperm capacitation, and decapacitation factors (DFs), and these have been investigated in many mammalian species [2,4,6,[9][10][11]. Kawakami et al [6] used FITC-lectins to investigate GP adhesion to the surface of canine caudal epididymal sperm and ejaculated spermatozoa, and the results showed that PHA-E-lectin did not bind to caudal epididymal sperm, but did bind to ejaculated sperm.…”

Methods of Assessment of Cryopreserved Semen

“…Acrosomal status may be assessed using lectins, such as peanut agglutinin from Arachis hypogaea (PNA) or Pisum Sativum agglutinin (PSA), conjugated with different fluorescent probes like fluorescein isothiocyanate (FITC), phycoerythryn (PE) or Alexa Fluor ® , Kawakami et al, 2002;Nagy et al, 2004;Partyka et al, 2010;Peña et al, 2001;Rijsselaere et al, 2005). For human sperm concanavalin A lectins (ConA) is used as well (Holden et al, 1990).…”

Effect of freezing rate on acrosome and chromatin integrity in ram semen

“…Fluorescein lectin staining assay (FITC-conjugated Pisum sativum agglutinin (FITC PSA)): Acrosome integrity was assessed using FITC PSA (12). Briefly, 20 μl of diluted semen was re-suspended in 500 μl PBS and centrifuged at 2000 rpm for 20 min; the supernatant was then discarded.…”