Epididymal Cat Research Articles

Exposure to bromoxynil octanoate herbicide induces oxidative stress, inflammation, and apoptosis in testicular tissue via modulating NF-кB pathway.

Bromoxynil octanoate (BO) is a herbicide necessary for plant growth and production. However, it may cause damage to environment and humans. This study aimed to investigate the potential testicular toxicity of BO and its possible underlying mechanisms. Male Albino (Sprague Dawley) rats were administered BO in different doses (5, 10, 20, and 40mg/kg/BW; P.O.) daily for 21 days. Testicular function was evaluated by determining count and viability of epididymal sperm, and testosterone. In addition, the following parameters were assessed; MDA, NO, and H2O2 as oxidative stress markers; SOD, CAT, GPx, GST, and GSH as antioxidant markers; NF-ĸB-P65 and IL-18 as inflammatory markers; caspase-9 and caspase-3 as apoptotic markers; gene expression of NF-ĸB-P65, TNF-α, BAX, Bcl-2, and caspase-3; and histopathological examination of epididymis and testis sections. The results showed a significant (P<0.05) increase in MDA, NO, H2O2, IL-18, and caspase-9 content, NF-ĸB-P65, TNF-α, Bax, and Caspase-3 expression as compared to control. Furthermore, the count and viability of epididymal sperm, testosterone level, SOD, CAT, GPx, GST, and GSH content, and Bcl-2 expression showed a significant (P<0.05) decrease as compared to control. In conclusion BO-induced testicular damage by altering oxidation, inflammation, and apoptosis.

Mito-Tempo improves acrosome integrity of frozen-thawed epididymal spermatozoa in tomcats.

In tomcats, epididymal spermatozoa provide an additional source of male gametes available for cryopreservation. While this procedure is feasible, the survival rate and motility of epididymal cat spermatozoa are both low after thawing. Cryopreservation is known to induce oxidative stress in spermatozoa, with mitochondria and the plasma membrane being the two major generation sites, and an imbalanced presence of free radicals is a possible cause for this low survival rate. Different antioxidants have been tested before for their effect on cryopreserved cat spermatozoa quality, with varying results. Here, we used Mito-Tempo, which is a synthetic mitochondria-targeted antioxidant and a specific scavenger of the mitochondrial superoxide system. By supplementing Mito-Tempo with the freezing extender, we aimed to improve the sperm quality of frozen-thawed cat epididymal spermatozoa. Epididymal spermatozoa obtained from twelve tomcats were assessed for motility and concentration. Prior to freezing, samples were diluted in TRIS buffered extender with egg yolk and glycerol and divided into five aliquots supplemented with 0 (control), 0.5, 5, 50, and 1005M of Mito-Tempo. After thawing, sperm motility, concentration, morphology, plasma membrane integrity, acrosome integrity, and mitochondrial membrane potential were evaluated. A Friedman rank sum test with a Bonferroni post-hoc test was used to determine statistical in-between group differences in post-thaw semen parameters. The results indicated a slight improvement in acrosome integrity across all groups that were supplemented with Mito-Tempo, with the group that received 55M of Mito-Tempo showing the greatest improvement [(median of 67.99%, IQR of 5.55) compared to the control group (median of 65.33%, IQR of 7.75; P = 0.05)]. For all other sperm parameters, no significant differences (P > 0.05) were detected between different Mito-Tempo concentrations. These findings highlight the protective effect of Mito-Tempo on acrosome integrity and suggest that 55M is the most effective concentration for maintaining acrosome integrity. Since Mito-Tempo has shown a positive effect on multiple sperm parameters in other species, such as men, boars, roosters, rams, and bulls, we need to conclude that species-specificity may play a role here.

Retained fertilizing capability in cryopreserved feline spermatozoa.

Sperm cryopreservation offers a long-term preservation of male genetic materials for future assisted reproductive technologies. However, dramatic changes in temperature during freezing and thawing injure sperm cells. While motility is essential for AI and membrane integrity is crucial for in vitro fertilization (IVF), sperm DNA integrity is a common index of fertilizing capability required for AI, IVF and intracytoplasmic sperm injection (ICSI). In endangered felids died unexpectedly, attempts have been made to recover as many DNA intact spermatozoa as possible from epididymis and testis to increase the opportunity to produce offspring in future. Although sperm from caudal epididymis has shown retained fertilizing capability after freezing and thawing (27.3% conception rate after unilateral intrauterine insemination), sperm recovery from the corpus epididymis has been suggested as an alternative to increase the amount of preserved genetic materials. To improve epididymal sperm quality, pre-treatment with single-layer centrifugation resulted in selection of sperm cells with intact DNA while post-thaw treatment with extracellular ATP incubation promoted the blastocyst rate. Cold storage of domestic cat testis for 7days at 4°C demonstrated <1% of sperm cells with fragmented DNA. Moreover, isolated testicular sperm cells, stored for 7days at 4°C, produced after ICSI poorer percentages of cleavage, morula and blastocyst than the fresh control. In wild felids, a death-to-necropsy time of 2hr after a jungle cat (Felis chaus) aged 10years died during anaesthesia plus another necropsy-to-sperm recovery time of 25hr has been reported to yield the post-thawed testicular sperm with 22.2% intact DNA. In summary, the chromatin structure of feline ejaculated and epididymal sperm seems to be tolerated to cold storage and cryopreservation; thus, fertilizing capability is well protected. In contrast, the cat testicular sperm DNA is generally damaged through the cryopreservation.

Effect of extracellular adenosine 5′-triphosphate on cryopreserved epididymal cat sperm intracellular ATP concentration, sperm quality, and in vitro fertilizing ability

Intracellular adenosine 5′-triphosphate (ATP) is essential for supporting sperm function in the fertilization process. During cryopreservation, damage of sperm mitochondrial membrane usually leads to compromised production of intracellular ATP. Recently, extracellular ATP (ATPe) was introduced as a potent activator of sperm motility and fertilizing ability. This study aimed to evaluate (1) levels of intracellular ATP in frozen–thawed epididymal cat sperm after incubation with ATPe and (2) effects of ATPe on epididymal cat sperm parameters after freezing and thawing. Eighteen male cats were included. For each replicate, epididymal sperm from two cats were pooled to one sample (N = 9). Each pooled sample was cryopreserved with the Tris–egg yolk extender into three straws. After thawing, the first and second straws were incubated with 0-, 1.0-, or 2.5-mM ATPe for 10 minutes and evaluated for sperm quality at 10 minutes, 1, 3, and 6 hours after thawing and fertilizing ability. The third straw was evaluated for intracellular ATP concentration in control and with 2.5-mM ATPe treatment. Higher concentration of intracellular sperm ATP was observed in the samples treated with 2.5-mM ATPe compared to the controls (0.339 ± 0.06 μg/2 × 106 sperm vs. 0.002 ± 0.003 μg/2 × 106 sperm, P ≤ 0.05). In addition, incubation with 2.5-mM ATPe for 10 minutes promoted sperm motility (56.7 ± 5.0 vs. 53.3 ± 4.4%, P ≤ 0.05) and progressive motility (3.1 ± 0.2 vs. 2.8 ± 0.4, P ≤ 0.05), mitochondrial membrane potential (36.4 ± 5.5 vs. 28.7 ± 4.8%, P ≤ 0.05), and blastocyst rate (36.1 ± 7.0 and 28.8 ± 7.4%, P ≤ 0.05) compared with the controls. In contrast, ATPe remarkably interfered acrosome integrity after 6 hours of postthawed incubation. In sum, the present finding that optimal incubation time of postthaw epididymal cat sperm under proper ATPe condition might constitute a rationale for the studies on other endangered wild felids regarding sperm quality and embryo development.

Determination of appropriate cryopreservation protocols for epididymal cat spermatozoa.

Effects of Equex and glycerol additions and sample dilution step on frozen-thawed epididymal cat spermatozoa were investigated. The epididymal sperm pellets were resuspended in extenders using one- (groups III and IV) or two- (groups I, II, V and VI) step dilution. For one-step dilution, the pellets were resuspended in plain egg yolk-Tris medium (EYT)+5% glycerol with (IV)/without (III) 0.5% Equex and cooled (4(°) C, 1h). For two-step dilution, the pellets were resuspended in EYT (I and V) and in EYT+3% glycerol (II and VI), cooled and further diluted with EYT+10% glycerol with (I)/without (V) 1% Equex and with EYT+7% glycerol with (II)/without (VI) 1% Equex. Immediately after freeze-thawing, no differences (p>0.05) were found in the motility, viability and membrane integrity (HOST) among the groups except the lowest HOST in IV (p=0.005 to p=0.04). The acrosome integrity (FITC) in group I was comparable to that in group II (p>0.05) and was higher than the rest (p<0.001 to p=0.02). At 2h after thawing, the motility, viability and HOST were comparable among the groups (p>0.05) except the lower percentages of viability in III (p=0.008 to p=0.3) and of HOST in IV (p=0.005 to p=0.2). Two-step dilutions with Equex (I, II) were more beneficial for the FITC at 2h than without Equex (V) (p=0.005 and p=0.02) and than one-step dilutions (III, IV) (p<0.001 to p=0.02). In conclusion, epididymal cat sperm quality after freeze-thawing could be improved when Equex was added and two-step dilution was performed during freezing. The extenders prepared for the first step of dilution could be with (3%) or without (0%) glycerol.

DNA fragmentation and sperm head morphometry in cat epididymal spermatozoa

Sperm DNA fragmentation is an important parameter to assess sperm quality and can be a putative fertility predictor. Because the sperm head consists almost entirely of DNA, subtle differences in sperm head morphometry might be related to DNA status. Several techniques are available to analyze sperm DNA fragmentation, but they are labor-intensive and require expensive instrumentations. Recently, a kit (Sperm-Halomax) based on the sperm chromatin dispersion test and developed for spermatozoa of different species, but not for cat spermatozoa, became commercially available. The first aim of the present study was to verify the suitability of Sperm-Halomax assay, specifically developed for canine semen, for the evaluation of DNA fragmentation of epididymal cat spermatozoa. For this purpose, DNA fragmentation indexes (DFIs) obtained with Sperm-Halomax and terminal deoxynucleotidyl transferase–mediated nick-end labeling (TUNEL) were compared. The second aim was to investigate whether a correlation between DNA status, sperm head morphology, and morphometry assessed by computer-assisted semen analysis exists in cat epididymal spermatozoa. No differences were observed in DFIs obtained with Sperm-Halomax and TUNEL. This result indicates that Sperm-Halomax assay provides a reliable evaluation of DNA fragmentation of epididymal feline spermatozoa. The DFI seems to be independent from all the measured variables of sperm head morphology and morphometry. Thus, the evaluation of the DNA status of spermatozoa could effectively contribute to the completion of the standard analysis of fresh or frozen semen used in assisted reproductive technologies.

Impact of Ultra‐Rapid Freezing on the Motility, Morphology, Viability and Acrosome Integrity of Epididymal Cat Sperm Diluted in Sucrose‐Based Extenders

The objective of the present study was to investigate the influence of different sucrose-based extenders on the motility, morphology, viability and acrosomal integrity of epididymal cat spermatozoa cryopreserved by ultra-rapid freezing method. Nine cats were castrated, and collected semen was diluted 1:1 with Dulbecco`s phosphate-buffered saline-BSA1%-based extender supplemented with different sucrose concentrations (0, 0.25, 0.4 and 0.6m). After ultra-rapid freezing, samples were thawed and sperm motility, morphology, viability and acrosome status were assessed. At thawing, the number of progressively motile (p<0.01) and morphologically normal (p<0.01) sperm was higher in the sucrose-supplemented groups than in the sucrose-free group. Viability of spermatozoa cryopreserved without sucrose was significantly reduced. In extender supplemented with 0.4m sucrose, spermatozoa viability showed higher values (57.0±4.7; p<0.01). No significant differences were detected among groups for sperm acrosome integrity. Results support that cat sperm survive after ultra-rapid freezing using sucrose as a cryoprotectant, and the best results were achieved when 0.4m of sucrose was used. This is the first report on sperm ultra-rapid freezing of cat sperm and further studies on extenders, sperm management or cryovials should be carried out to improve sperm cryosurvival.

Sperm‐TALP: An Alternative Extender for Retrieving and Diluting Epididymal Sperm in the Domestic Cat

Effects of sperm-TALP (TALP) on the quality of fresh-extended and frozen-thawed epididymal cat sperm were evaluated. The epididymides suspended in Tris-glucose-citrate solution (Tris), a conventional medium, and TALP were cut into small pieces to recover epididymal sperm. In experiment 1, the sperm pellets remained after centrifugation were re-suspended (1:2, v/v) in Tris and TALP. The sperm quality in all four groups, that is, sperm retrieved with Tris (I and II) or TALP (III and IV) and diluted with Tris (I and III) or TALP (II and IV) was assessed. The sperm motility at the 0-h incubation in TALP-TALP was superior to that of the rest (p<0.001 to p=0.04). At the 2-h incubation, the motility in Tris/TALP-TALP was greater than that in Tris/TALP-Tris (p≤0.001). In experiment 2, after centrifugation, the sperm pellets were added with freezing extenders and frozen. The thawed sperm previously retrieved from the epididymides with Tris and TALP were allotted so as not to further diluted (Tris/TALP-O) and to further diluted (1:1, v/v) with Tris (Tris/TALP-Tris) and TALP (Tris/TALP-TALP) and were evaluated the quality. At both incubation times, the motility of frozen-thawed sperm recovered with TALP (TALP-O/Tris/TALP) was comparable with or significantly higher than that in the Tris groups (Tris-O/Tris/TALP; p=0.003 to p>0.05). The motility and viability of thawed sperm in Tris-Tris were significantly decreased during the 2-h incubation (p=0.007 for the motility and p=0.01 for the viability). In both experiments, neither type of diluent (Tris vs TALP) nor incubation time (0 vs 2h) significantly affected the sperm membrane integrity under hypo-osmotic condition (p>0.05). According to beneficial effects on the quality of fresh-extended and frozen-thawed sperm demonstrated, sperm-TALP could be used as an alternative medium for recovering sperm from the epididymides and for diluting epididymal sperm in the domestic cat.

Effect of Different Extenders onIn VitroCharacteristics of Feline Epididymal Sperm During Cryopreservation

To evaluate and compare the efficacy of various extenders for the cryopreservation of epididymal cat spermatozoa, two experiments were planned. Bovine and equine commercial extenders in the experiment 1 and TRIS-egg yolk-based extenders in experiment 2 were separately studied since the number of sperm collected per cat is reduced. Epididymal sperm samples were packaged into 0.25-ml straws and frozen. Vigour, motility, morphology, acrosome status, sperm viability and functional membrane integrity were assessed at collection, after cooling and after thawing, while DNA integrity was evaluated at 0- and 6-h post-thaw. Experiment 1 compared the effect of three non-feline commercial extenders - based on TRIS-egg yolk (Triladyl), egg-yolk-free medium (AndroMed) and skimmed milk-egg yolk (Gent) - on the quality of frozen-thawed epididymal cat sperm. Values for sperm motility and functional membrane integrity in cooled sperm diluted in Triladyl were higher (p<0.001) than those recorded for Andromed and Gent. Except sperm morphology, the other assessed characteristics showed significant higher values in frozen-thawed sperm diluted in Triladyl than in Andromed and Gent extenders. Experiment 2 analysed the effects of three TRIS-egg yolk-based extenders, one non-feline commercial (Triladyl) and the other two prepared using different monosaccharides (glucose and fructose), on freezing-thawed sperm. Results showed that specifically prepared extenders for cryopreservation of feline spermatozoa performed better than the commercial extender Triladyl, although sperm quality during the freezing-thawing process did not significantly differ associated with the type of monosaccharide (glucose vs fructose) added to the mentioned extenders. Although TRIS-egg yolk-based extenders prepared in experiment 2 improved sperm cryoprotection, Triladyl remains a good option for practitioners who, for ease of use and availability, prefer to work with commercial extenders.

Cryopreservation of epididymal cat spermatozoa: effects of in vitro antioxidative enzymes supplementation and lipid peroxidation induction

Reactive oxygen species and lipid peroxidation reaction, causes of sperm damage, can be diminished by action of antioxidative enzymes. This study aimed to investigate effects of (1) the antioxidative enzymes; catalase, glutathione peroxidase and superoxide dismutase, on epipididymal cat sperm quality and (2) the lipid peroxidation reaction induced by a transition metal (ferrous ion (II); Fe 2+) on sperm quality during the cryopreservation process. Epididymal spermatozoa harvested from 39 male cats were pooled and divided into 13 aliquots (n = 13). Each aliquot was resuspended with either a Tris egg yolk extender I (control; EE-I), or the Tris egg yolk extender I supplemented with 200 U/mL catalase (EE-CAT), or 10 U/mL glutathione peroxidase (EE-GPx), or 600 U/mL superoxide dismutase (EE-SOD), and then cryopreserved. After thawing, each sperm sample was subdivided into two groups; with and without lipid peroxidation induction (EE-I plus Fe 2+, EE-CAT plus Fe 2+, EE-GPx plus Fe 2+ and EE-SOD plus Fe 2+). Subjective sperm motility, membrane, and acrosome integrity were evaluated at the time of collection, after cooling, and at 0, 2, 4, and 6 h after thawing. Motility patterns assessed by computer-assisted sperm analysis (CASA), mitochondrial activity, and DNA integrity were evaluated during post-thaw incubation, whereas percentage of lipid peroxidation was detected at 0 and 6 h after thawing. The results demonstrate that catalase supplementation reduced linear motility and subjective motility immediately and 2 h after thawing (P < 0.05). Catalase supplementation, however, improved DNA integrity at 4 h (P < 0.05). Supplementation with glutathione peroxidase, compared to the control group, had a statistically significant positive effect on subjective motility at 0 and 6 h, linear motility at 6 h, mitochondrial activity at 6 h, membrane integrity at 2 and 6 h, and DNA integrity at 4 h after thawing. Although superoxide dismutase had a positive effect on sperm membrane integrity at 2 h after thawing (P < 0.05), it significantly reduced membrane integrity after cooling, linear motility at thawing, and acrosome integrity at 2 h after thawing. None of the three selected antioxidative enzymes significantly influenced acrosome integrity and none reduced the level of lipid peroxidation. Furthermore, induction of the lipid peroxidation reaction by Fe 2+ negatively affected most of the sperm quality parameters, i.e., motility and DNA integrity, during post-thaw sperm incubation (P < 0.05). After thawing, there were, however, no significant differences between the control plus Fe 2+ and the antioxidative enzymes supplementation plus Fe 2+ groups. We can conclude that (1) glutathione peroxidase exhibits positive effects on post-thaw epididymal cat spermatozoa; but (2) none among the selected antioxidative enzymes could improve all sperm quality parameters; and (3) the lipid peroxidation reaction may be one cause of post-thaw epididymal sperm damage in cats, but the concentrations of antioxidative enzymes used in this study could not protect cat spermatozoa from lipid peroxidation induction.

Single-layer centrifugation through colloid selects improved quality of epididymal cat sperm

The objectives were to determine the: 1) extent of epithelial and red blood cell contamination in epididymal cat sperm samples recovered by the cutting method; 2) efficacy of simple washing, single-layer centrifugation (SLC), and swim-up for selecting epididymal cat sperm; and 3) effects of freezing and thawing on cat sperm selected by various techniques. Ten unit samples were studied; each contained sperm from the cauda epididymides of four cats (total, ∼200×106 sperm) and was equally allocated into four treatments: 1) simple washing, 2) single-layer centrifugation through colloid prior to cryopreservation (SLC-PC), 3) single-layer centrifugation through colloid after cryopreservation (SLC-AC), and 4) swim-up. Centrifugation (300×g for 20min) was done for all methods. The SLC-PC had a better recovery rate than the SLC-AC and swim-up methods (mean±SD of 16.4±8.7, 10.7±8.9, and 2.3±1.7%, respectively; P<0.05). The SLC-PC, SLC-AC and swim-up samples contained less red blood cell contamination than simple washed samples (0.02±0.01, 0.02±0.04, 0.03±0.04, and 0.44±0.22×106cells/mL, respectively; P<0.05). Although the proportion of sperm with head abnormalities did not differ among selection methods (P>0.05), SLC-PC yielded the highest percentage of sperm with normal midpieces and tails (P<0.05), due to the lowest proportion of coiled tails (P<0.05). Furthermore, the SLC-PC was as effective as swim-up in removing sperm with proximal droplets, and selecting motile sperm, as well as those with intact membranes and DNA (P>0.05). In conclusion, both SLC-PC and swim-up improved the quality of epididymal cat sperm, including better morphology, membrane and DNA integrity, and removal of cellular contamination. However, SLC had a better sperm recovery rate than swim-up.

Quality and fertilizing ability of electroejaculated cat spermatozoa frozen with or without Equex STM Paste

An optimal protocol for cat semen cryopreservation has not yet been defined. Addition of Equex STM Paste has been tested for epididymal cat spermatozoa but not for ejaculated cat spermatozoa. Furthermore, the effect of Equex STM Paste on fertilizing ability of cryopreserved semen has never been evaluated in that species. Therefore, the aims of the current study were to investigate if addition of Equex STM Paste to a freezing extender for electroejaculated cat (Felis catus) semen would improve postthaw sperm quality and if sperm fertilizing ability after cryopreservation with or without Equex STM Paste was preserved. Semen was collected by electroejaculation and frozen in a Tris-glucose-citrate egg yolk extender supplemented with (0.5% vol/vol) or without Equex STM Paste. In Experiment 1, sperm motility, membrane integrity, and acrosomal status were determined immediately after collection and at 0, 3, and 6 h postthaw. In Experiment 2, frozen semen from the two groups was used for in vitro fertilization (IVF) of in vitro–matured cat oocytes. Cleavage rate was recorded 30 h after IVF, and embryo development was evaluated on Days 6 and 7 of culture. In Experiment 1, the rate of motile spermatozoa after freezing-thawing was higher when Equex STM Paste was added to the freezing extender, but progressive motility score was not influenced (P > 0.05). Sperm membrane integrity was positively affected (P < 0.05) by the addition of the detergent. Intact acrosomes after thawing were similar (P > 0.05) between groups. Even if the decreasing rates of motility and membrane integrity were more rapid in presence of Equex than those in controls, total motility and sperm viability were similar at 3 and 6 h after thawing (P > 0.05). In Experiment 2, there was no difference in fertilizing ability and embryo development between the two groups (P > 0.05). The results of this study demonstrate that the addition of Equex STM Paste in the freezing extender avoids the loss of motile spermatozoa and maintains fertilizing ability of frozen-thawed spermatozoa.

Cryopreservation of feline epididymal spermatozoa from dead and alive animals and its use in assisted reproduction

Cryopreservation of gametes is an important tool in assisted reproduction programmes; long-term storage of oocytes or spermatozoa is necessary when in vitro fertilization (IVF) or artificial insemination is to be performed at a future date. Cryopreservation of epididymal spermatozoa offers a potential tool for rescuing genetic material from males of endangered populations. The objectives of this work were to: (1) examine sperm motility, viability, abnormality and acrosome integrity of frozen-thawed domestic cat epididymal spermatozoa; and (2) evaluate the same cryopreservation method on wild feline spermatozoa, needed to preserve their genetic resources. Epididymides were collected from 20 domestic cats during routine neutering procedure and from two wild felines at autopsy. The sperm samples, diluted with 4% glycerol/Tris/egg yolk, were loaded into 0.25 ml mini-straws, exposed to nitrogen vapour and stored in liquid nitrogen. After 4 weeks, samples were thawed and re-evaluated. The quality of each fresh and frozen-thawed sperm sample was tested by determining the motility (54.7 +/- 11.3% and 32 +/- 13.1% respectively for cat spermatozoa; 38.3 +/- 18.7% and 21.5 +/- 16.8% respectively for tiger spermatozoa), viability (74.3 +/- 8.6% and 45.2 +/- 9.4% respectively for cat spermatozoa; 42.4 +/- 14.5% and 33.5 +/- 12.9% respectively for wild felid spermatozoa), morphology and acrosomal status. The present study showed that feline epididymal spermatozoa can be frozen in egg-yolk extender with 4.0% glycerol in 0.25 ml straws. The procedure used in the present study for epididymal cat sperm cryopreservation may be applied to bank the genetic resources of wild felid species.

Detection of Lipid Peroxidation Reaction in Frozen‐Thawed Epididymal Cat Spermatozoa Using BODIPY581/591 C11

Lipid peroxidation is considered to be an important cause of sperm membrane damage, resulting in an apparent reduction of reproductive fecundity. Recently, a new lipophilic fluorescent dye probe (BODIPY(581/591) C11; Invitrogen Singapore Pte Ltd, Singapore) has been demonstrated to be a highly sensitive indicator for the physiological oxidation of cell membrane fatty acids. The objectives of this study were: (i) to detect lipid peroxidation in frozen-thawed epididymal cat spermatozoa using the BODIPY(581/591) C11 and (ii) to study the effect of semen extender in protecting sperm membrane from lipid peroxidation [100-mm ferrous ion, ferrous sulphate (FeSO(4))]. Epididymal cat spermatozoa were collected from eight male cats. Two straws of sperm sample from each cat were cryopreserved. After thawing, the semen extender from the first straw was removed and the sperm pellet was resuspended with Tris buffer (control). The semen sample from the other straw was equally divided: one sample contained semen extender (treatment A) and one contained no extender (treatment B); both were incubated with FeSO(4). Semen samples were labelled with the BODIPY(581/591) C11 probe and evaluated by flow cytometry at 0 and 6 h after thawing (control), 6 h after the addition of FeSO(4) (treatment A), and 30 min and 6 h after the addition of FeSO(4) (treatment B), respectively. The percentage of lipid peroxidation was higher after treatment B (51.3 +/- 23.9) and 6-h incubation compared with the control and treatment A (p < 0.05). Furthermore, the percentage of lipid peroxidation after treatment B increased during the incubation time (p < 0.05). In conclusion, the high percentage of lipid peroxidation after treatment B indicated that FeSO(4) induced membrane damage in cat spermatozoa, which could be detected by BODIPY(581/591) C11. This marker is suggested to be a beneficial tool for the evaluation of lipid peroxidation. Furthermore, the use of semen extender seemed to protect cat spermatozoa membranes from lipid peroxidation.

Survival of Frozen‐Thawed Cat Spermatozoa Pre‐Cooled in the Epididymides

Sperm recovery from epididymides and their cryo-preservation require particular media and equipment not always available in the field. This study aimed to compare the quality of frozen-thawed epididymal cat spermatozoa pre-cooled in an extender vs. cooled in the epididymides. Testes with attached epididymides from 23 cats subjected to routine orchidectomy were allocated into two groups; 2-day (n = 10) and 4-day cold storage (n = 13). Spermatozoa from one epididymis of each pair were recovered, evaluated, extended in a Tris egg yolk extender, cooled to 5 degrees C and stored for either 2 or 4 days prior to freezing (Treatment 1). The remaining testis attached with the epididymis was stored at 5 degrees C in a Tris-buffered solution for either 2 or 4 days, before the spermatozoa were harvested, evaluated and frozen (Treatment 2). The spermatozoa were evaluated for percentage of motility, viability, intact acrosomal integrity and morphology. Sperm evaluations were performed prior to freezing and after freezing-thawing. The spermatozoa maintained in the epididymes yielded similar quality after cold storage and after freeze-thawing in comparison to that maintained in the extender at both storage times (p > 0.05). However, cold storage of spermatozoa for 4 days resulted in a reduction in motility compared to that cold stored for 2 days (p < 0.05). Similarly, freezing of spermatozoa pre-cooled for 4 days resulted in lower percentages of motility, viability and intact acrosome than that pre-cooled for 2 days (p < 0.05). A higher number of spermatozoa with simple bent tail and coiled tail were found in the samples maintained in the epididymides than in the extender after 4-day storage. The results indicated that cat spermatozoa can be cold stored in the epididymides prior to being harvested and cryopreserved in a distant laboratory. This technology is an alternative to rescue male gamete when animals are castrated or unexpectedly die under field conditions.

Incubation of Post‐Thaw Epididymal Cat Spermatozoa with Seminal Plasma

In domestic cats, epididymal spermatozoa have lower initial motility and viability than ejaculated spermatozoa and it is possible that seminal plasma compounds are behind these effects. The aim of this study was to investigate whether co-incubation of post-thaw epididymal cat spermatozoa with seminal plasma was able to improve sperm quality. Epididymal cat spermatozoa from 11 cats were cryopreserved. After thawing, each sperm sample was divided into two aliquots, centrifuged and incubated with two different media; Tris buffer (control) or pooled seminal plasma (treatment). Sperm quality was observed at 0, 2, 4 and 6 h after incubation. The results demonstrated that all of the sperm parameters except acrosome integrity were lower in the treatment group compared to the control group (p < 0.05); the percentages of motility (46.4 +/- 15.4 vs 40.0 +/- 9.4), the scores of progressive motility (3.1 +/- 0.4 vs 2.8 +/- 0.5), the percentages of spermatozoa with intact plasma membrane (46.3 +/- 9.7 vs 39.6 +/- 8.9) and intact acrosome (36.5 +/- 16.2 vs 32.9 +/- 15.1), as well as at all time points. In conclusion, the seminal plasma seems less beneficial to the post-thaw epididymal cat spermatozoa than the Tris buffer.

Computer-assisted sperm analysis of fresh epididymal cat spermatozoa and the impact of cool storage (4 °C) on sperm quality

Epididymal cat sperm is commonly used for in vitro fertilization. Because of the high variability in preparation protocols and methods of evaluation, sperm quality may vary considerably between experiments and laboratories. The aims of the present study were (1) to describe an epididymal sperm preparation protocol to produce clean, highly motile samples using density gradient centrifugation, (2) to provide reference values of computer-assisted semen analysis (CASA) parameters of fresh epididymal cat sperm after density gradient centrifugation and (3) to investigate the effect of cool storage on various spermatozoa characteristics. After slicing the epididymides, viable and motile sperm cells were isolated using Percoll ® centrifugation. Sperm motility parameters were subsequently assessed using CASA in experiment 1. In experiment 2, fresh (day 0) sperm samples were evaluated for motility parameters (HTR) and stained for assessment of acrosomal status (FITC-PSA), morphology (eosin/nigrosin (E/N)), membrane integrity (E/N and SYBR ®14-PI) and DNA fragmentation (TUNEL). After addition of a Tris–glucose-citrate diluent containing 20% egg yolk, samples were cooled to 4 °C and reassessed on d1, d3, d5, d7 and d10. Cool storage impaired most motility and velocity parameters: MOT, PMOT, VAP, VSL, VCL, BCF, RAPID and the percentage of normal spermatozoa showed a decrease over time ( P < 0.05) as compared to fresh samples. In contrast, STR, ALH, membrane integrity, DNA fragmentation and the percentage of acrosome intact spermatozoa were not affected by cool storage. However, the influence of cool storage of cat spermatozoa on subsequent in vitro embryo development and quality after IVF requires further investigation.

The effect of antioxidants on motility, viability, acrosome integrity and DNA integrity of frozen-thawed epididymal cat spermatozoa

Antioxidants partially ameliorated the negative effects of reactive oxygen species (ROS) produced during cryopreservation. The objective of the present study was to investigate the effect of cysteine and a water-soluble vitamin E analogue on the quality of frozen-thawed epididymal cat spermatozoa. Epididymal spermatozoa were collected from eight male cats and divided into three aliquots; these were resuspended with a tris egg yolk extender I (EE-I), or the same extender supplemented with 5mM dl-cysteine (EE-C) or with 5mM of a water-soluble vitamin E analogue (EE-Ve). Prior to the freezing step, sperm suspensions were added to the extender with Equex STM paste (EE-II). Sperm motility, progressive motility, membrane integrity, and acrosome status were evaluated at collection, after cooling, and at 0, 2, 4, and 6h post-thaw. Sperm DNA integrity was evaluated at 0 and 6h post-thaw. Relative to the control group, supplementation with vitamin E improved (P<0.05) post-thaw motility (69.4+/-5.6%), progressive motility (3.9+/-0.3), and membrane integrity (65.1+/-8.1%) immediately after thawing, whereas cysteine supplementation improved (P<0.05) post-thaw motility after 2h of incubation (53.8+/-12.2%) and DNA integrity after 6h (84.1+/-4.4%). However, neither antioxidant significantly increased the acrosome integrity of frozen-thawed spermatozoa. In conclusion, cysteine or vitamin E supplementation of tris egg yolk extender improved motility, progressive motility and integrity of the sperm membrane and DNA of frozen-thawed epididymal cat spermatozoa.

Influence of extender and packaging on post-thaw survival of epididymal cat spermatozoa

Influence of extender and packaging on post-thaw survival of epididymal cat spermatozoa

12 COMPUTER-ASSISTED SPERM ANALYSIS OF FRESH EPIDIDYMAL CAT SPERMATOZOA AND THE IMPACT OF COOLED STORAGE (4°C) ON SPERM QUALITY

Feline epididymal sperm is commonly used for in vitro fertilization. It also yields the opportunity to conserve genetic material from valuable males that suddenly die. Epididymal sperm quality parameters vary considerably among laboratories, implicating the need for objective evaluation methods. The aim of the present study was to describe reference values of computer-assisted sperm analysis (CASA) parameters of fresh epididymal cat sperm and to assess the effect of prolonged cooled storage (4�C) on various sample characteristics. Epididymides obtained from tomcats after routine orchiectomy (2–4 pairs/replicate) were sliced to release spermatozoa. The sperm suspension was placed on a 2-layer gradient and, after centrifugation, the sperm pellet was recovered. In Experiment 1 (20 replicates), sperm motility parameters were assessed immediately after retrieval (T0) using the Hamilton Thorne analyzer Ceros 12.1 (HTR; Hamilton Thorne Biosciences, Beverly, MA, USA). In Experiment 2, fresh (T0) sperm samples (4 replicates) were evaluated for motility parameters (HTR), acrosomal status (FITC-Pisum sativum agglutinin staining), morphology (eosin/nigrosin (E/N) staining), and membrane integrity (E/N and SYBR�-14-propidium iodide staining; Molecular Probes, Inc., Eugene, OR, USA). After addition (1:2) of a Tris-glucose-citrate diluent containing 20% egg yolk, samples were cooled and reassessed on Days 1 (T1), 3 (T3), 5 (T5), 7 (T7), and 10 (T10). Results were analyzed in a mixed linear model, with replicate as random factor and time as fixed effect (S-PLUS 7.0; Insightful Corp., Seattle, WA, USA). Results of Experiment 1 were as follows (mean � SD): motility (MOT): 80.8% � 23.5; progressive motility (PMOT): 69.9% � 23.2; velocity average pathway (VAP): 98.7 µm s–1 � 24.2; velocity straight line (VSL): 89.3 µm s–1 � 25.4; velocity curved line (VCL): 134.8 µm s–1 � 31.9; amplitude lateral head (ALH): 4.3 µm � 2.0; beat cross frequency (BCF): 34.6 Hz � 7.0; and straightness (STR): 89.6% � 6.6. In Experiment 2, MOT, PMOT, VAP, VSL, VCL, BCF, and the percentage of normal spermatozoa showed a decrease over time (P &lt; 0.05) compared to fresh samples, starting from T1, T3, T5, T7, T5, T3, and T1, respectively. In contrast, STR, ALH, membrane integrity, and the percentage of acrosome-intact spermatozoa were not affected (P &gt; 0.05) by cooled storage. To summarize, we have presented a set of reference values for CASA-parameters of fresh, epididymal cat spermatozoa. Cooled storage impaired most motility parameters and lowered the percentage of normal spermatozoa, but did not influence membrane integrity or acrosomal status. The effect of cooled storage on DNA fragmentation of sperm and its subsequent influence on in vitro embryo development require further investigation.