Oviduct binding ability of porcine spermatozoa develops in the epididymis and can be advanced by incubation with caudal fluid

Abstract

Abstract.The sperm reservoir is formed when spermatozoa bind to the epithelium of the utero-tubal junction and caudal isthmus of the oviduct. It is an important mechanism that helps synchronize the meeting of gametes by regulating untimely capacitation and polyspermic fertilisation. This study investigated the influence of epididymal maturation and caudal fluid on the ability of spermatozoa to bind to oviduct epithelium using a model porcine oviduct explant assay. Spermatozoa from the rete testis, middle caput (E2-E3), middle corpus (E6) and cauda (E8) of Large White or Large White x Landrace boars at 10-14 months of age were diluted in modified Androhep solution and incubated with porcine oviduct explants. Results reported in this study support our hypothesis that testicular spermatozoa need to pass through the regions of the epididymis in order to acquire the ability to bind to the oviduct. There was a sequential increase in the number of spermatozoa that bound to oviduct explants from the rete testis to caudal epididymis. Binding of caudal spermatozoa to isthmic explants was the highest (15.0 ± 1.2 spermatozoa per 1.25 mm 2 ; mean ± standard error of the mean; P ≤ 0.05) and lowest by spermatozoa from the rete testis (2.0 ± 0.3 per 1.25 mm 2 ), and higher to isthmus from sows compared to gilts (35.8 ± 6.7 per 1.25 mm 2 vs. 14.8 ± 3.0 per 1.25 mm 2 ; P ≤ 0.05). Binding of ejaculated spermatozoa to porcine isthmus was higher than for caudal spermatozoa (26.3 ± 1.4 per 1.25 mm 2 vs. 15.0 ± 0.8 per 1.25 mm 2 ; P ≤ 0.05), and higher to porcine than to bovine isthmus (26.3 ± 2.3 per 1.25 mm 2 vs. 18.8 ± 1.9 per 1.25 mm 2 ; P ≤ 0.05). Incubation of spermatozoa from the caput and corpus in caudal fluid 2 increased the ability of spermatozoa to bind to oviduct epithelium (P ≤ 0.05). In conclusion, the capacity of testicular spermatozoa to bind to oviduct epithelium increases during their maturation in the epididymis, and can be advanced by components of the caudal fluid.

Heterologous Oviductal Cells Binding Capacity of Cryopreserved Equine Ejaculated and Epididymal Spermatozoa

“…The sperm kinematics of frozen-thawed ejaculated sperm were higher than corpus and cauda epididymal sperm, contrary to previous reports in horses [2,3,45,46], pigs [47], and goats [48], which observed that the motility parameters and PMI after thawing were similar in ejaculated and epididymal sperm [3]. Moreover, the TM and PM of cauda epididymal sperm were lower than that described by Papa et al [1] and Monteiro et al [3]; probably, the age factor may have influenced the results as stallions aged between 34 and 38 months were used.…”

“…The sperm cryopreservation causes damage to plasma membrane [55], leading to a reduced number of sperm with the ability to bind to oviductal cells [36]. However, in this study, the cryopreservation process did not affect the binding capacity of ejaculated or epididymal spermatozoa, unlike other studies that observed a decrease in binding capacity of frozen-thawed sperm to OECs [47,51,56]. Factors such as the freezing extender and/or freezing protocol used in this study may have provided greater protection to sperm during the cryopreservation process, preserving the binding capacity of ejaculated and epididymal sperm cells.…”

“…The sperm binding to oviductal epithelium has been shown to involve carbohydrate-protein interactions [53]. The porcine spermadhesins, AQN-type proteins, are associated with the sperm surface at ejaculation and contribute to the formation of the oviductal sperm reservoir through interaction with the glycoconjugates of the oviductal epithelium [37,47]. The PDC-19 proteins are secreted by the seminal vesicles of the bull, and these proteins are attached to the sperm membrane during ejaculation and bind to fucosylated molecules in the oviductal epithelium [20].…”

Antioxidant supplementation mitigates DNA damage in boar (Sus scrofa domesticus) spermatozoa induced by tropical summer

“…Motility and sperm head characteristics were derived from at least 200 spermatozoa across five random fields. This was achieved by loading each chamber of 38°C pre-warmed Leja Standard Count 4 Chamber Slides (Leja Products, Nieuw-Vennep, Netherlands) with 3 μL of 20 x 10 6 sperm/mL semen in BTS as previously described [61]. The CASA software was calibrated to the following settings: analysis set-up #7: BOAR; frames acquired, 40/sec; frame rate, 50 Hz; minimum contrast, 60%; minimum cell size, two pixels; minimum static contrast, 30%; straightness threshold, 71.4%; low average-path velocity (VAP) cut-off, 5.0 μm/sec; medium VAP cut-off, 22.0 μm/sec; low straight-line velocity (VSL) cut-off, 11.0 μm/sec; head size (non-motile), two pixels; head intensity (non-motile), 70 pixels; static head size, 0.10–10.0 pixels; static head intensity, 0.10–0.95 pixels; static elongation, 0–60; count slow cells as motile, YES; magnification, 3.20; video source, camera; video frequency, 50; brightfield, NO; illumination intensity, 2381 and temperature, 38°C.…”

Tropical summer induces DNA fragmentation in boar spermatozoa: implications for evaluating seasonal infertility

“…At least 200 spermatozoa across five random fields were examined per sample. Motility characteristics of spermatozoa were analysed as previously described (Peña et al 2015). The CASA software was calibrated to the following settings: analysis set-up #7: BOAR; frames acquired, 40 s À1 ; frame rate, 50 Hz; minimum contrast, 60%; minimum cell size, two pixels; minimum static contrast, 30%; straightness threshold, 71.4%; low average-path velocity (VAP) cut-off, 5.0 mm s À1 ; medium VAP cut-off, 22.0 mm s À1 ; low straight-line velocity (VSL) cut-off, 11.0 mm s À1 ; head size (non-motile), two pixels; head intensity (non-motile), 70 pixels; static head size, 0.10-10.0 pixels; static head intensity, 0.10-0.95 pixels; static elongation, 0-60; count slow cells as motile, YES; magnification, 3.20; video source, camera; video frequency, 50; brightfield, NO; illumination intensity, 2381 and temperature, 388C.…”