Time-dependent changes in cardiovascular function during copulatory behavior induced by the hand method in the male dog.

PURPOSE: Ejaculation in the male dog consists of three fractions. Observation of behavior and measurement of heart rate (HR), and plasma noradrenaline (NA) and adrenaline (Ad) concentrations were researched sequentially, and a fundamental examination of the features of sympathetic nerve activity during copulatory behavior induced by the hand method in the male dog was undertaken. METHODS: We investigated the breeding capability of male dogs. HR, plasma NA level and plasma Ad levels were measured during ejaculation induced by the hand method. RESULTS: HR was 125.8 ± 6.0 beats/min at rest, and peaked during mounting at 195.2 ± 8.2 beats/min. Moreover, HR at 3 min after the first fraction decreased to values similar to those at rest. Plasma NA and Ad concentrations during copulatory behavior induced by the hand method did not differ significantly from those at rest. However, although there was no significant difference, plasma NA concentration during ejaculation of the third fraction peaked at about 1.8 times the baseline value. CONCLUSIONS: In the male dog, excitation of sympathetic nerves of long duration during erection of the penis and ejaculation is questionable. However, inhibition of sympathetic nerves and activation of parasympathetic nerves is thought to occur during erection of the penis and ejaculation.

Effects of a simple method for determining the time of insemination and different methods on artificial insemination in common bottlenose dolphins (Tursiops truncatus).

In this study, we examined the usefulness of a simpler and more feasible method for determining the optimal timing of artificial insemination and the conditions for its success in six female common bottlenose dolphins. Pregnancy was successfully achieved in five dolphins by performing intrauterine insemination, using chilled semen stored for less than 3 days or frozen semen within 24 hr of exhibiting a peak serum estradiol (E2) level of 100 pg/mL or higher or on the day with a serum E2 level of approximately 100 pg/mL, measured with a simple measuring device. We concluded that the determining the optimal timing of intrauterine insemination by measuring serum E2 levels is a simpler and more useful method compared with the conventional approach.

Relaxin contributes to the elevation of monocytic myeloid-derived suppressor cells in peripheral blood of pregnant canines.

Tolerance towards fetal alloantigens in the maternal immune system is essential for maintaining pregnancy. Myeloid-derived suppressor cells (MDSCs) are immature myeloid cells characterized by their ability to suppress immune activity and maintain maternal-fetal immune tolerance. However, the mechanisms underlying MDSC induction have not been elucidated. Herein, we investigated the myeloid-derived suppressor cells (MDSCs) in the peripheral blood of pregnant canines and its induction mechanism. By analyzing the concentration of MDSCs in the peripheral blood of pregnant canines, elevation of MDSCs has been observed during pregnancy. In addition, MDSCs from pregnant canines inhibit T cell activation. These results suggest that the elevated MDSCs in canine pregnancy may contribute to reduces maternal immune activity. To clarify the cause of MDSCs elevation in canine pregnancy, we analyzed the relationship between pregnancy-related hormones (estradiol, progesterone, and relaxin) and MDSCs. Serum relaxin levels, but not estradiol and progesterone, were correlated with the ratio of monocyte MDSCs. Additionally, relaxin induced monocytic MDSCs as well as inhibited T cell activation in vitro. Therefore, relaxin contributes to the elevation of monocytic MDSCs in the peripheral blood of pregnant canines. Our findings highlight the novel role of relaxin in pregnancy and contribute to a better understanding of maternal-fetal immune tolerance.

Quality of cauda epididymal sperm immediately after collection and after freezing-thawing from Amur leopard cats (Prionailurus bengalensis euptilurus) and a local population of the subspecies Tsushima leopard cats.

In this study, cauda epididymal sperm were collected from Amur leopard cats with various causes of death as well as Tsushima leopard cats that underwent castration surgery, and sperm quality was compared with that in domestic cats. A sufficient number of sperm similar to those in domestic cats could be collected from the cauda epididymis of Amur leopard cats. However, in old leopard cats, no or very few cauda epididymal sperm were recovered, although there were no differences in sperm motility and sperm abnormality. There were no significant differences in sperm quality immediately after collection and after freezing-thawing of cauda epididymal sperm compared with corresponding estimates in domestic cats.

Establishment of a BRAF V595E-mutant canine prostate cancer cell line and the antitumor effects of MEK inhibitors against canine prostate cancer.

Canine prostate cancer (cPCa) is a malignant neoplasm with no effective therapy. The BRAF V595E mutation, corresponding to the human BRAF V600E mutation, is found frequently in cPCa. Activating BRAF mutations are recognized as oncogenic drivers, and blockade of MAPK/ERK phosphorylation may be an effective therapeutic target against BRAF-mutated tumours. The aim of this study was to establish a novel cPCa cell line and to clarify the antitumor effects of MEK inhibitors on cPCa in vitro and in vivo. We established the novel CHP-2 cPCa cell line that was derived from the prostatic tissue of a cPCa patient. Sequencing of the canine BRAF gene in two cPCa cell lines revealed the presence of the BRAF V595E mutation. MEK inhibitors (trametinib, cobimetinib and mirdametinib) strongly suppressed cell proliferation in vitro, and trametinib showed the highest efficacy against cPCa cells with minimal cytotoxicity to non-cancer COPK cells. Furthermore, we orally administered 0.3 or 1.0 mg/kg trametinib to CHP-2 xenografted mice and examined its antitumor effects in vivo. Trametinib reduced tumour volume, decreased phosphorylated ERK levels, and lowered Ki-67 expression in xenografts in a dose-dependent manner. Although no clear adverse events were observed with administration, trametinib-treated xenografts showed osteogenesis that was independent of dosage. Our results indicate that trametinib induces cell cycle arrest by inhibiting ERK activation, resulting in cPCa tumour regression in a dose-dependent manner. MEK inhibitors, in addition to BRAF inhibitors, may be a targeted agent option for cPCa with the BRAF V595E mutation.

Surgical intrauterine insemination with cat semen cryopreserved with Orvus ES paste or sodium lauryl sulfate.

The mean post-thaw sperm motilities of feline frozen semen prepared with 1% OEP or 3 g/ml SLS as a cryoprotective agent, in addition to 7% glycerin, were 35.0 ± 2.4 and 37.0 ± 2.5%, respectively, showing no significant difference. On unilateral intrauterine insemination (UIUI) using these semen samples at a sperm number of 40 × 10(6), the conception rate was 70.0% (7/10) in the OEP group and 30% (3/10) in the SLS group, showing that the rate was higher in the OEP group, but the difference was not significant. It was suggested that sperm in frozen semen showing the above qualities were transferred to the contralateral uterine horn on UIUI.

Effect of supplementation with the reduced form of coenzyme Q10 on semen quality and antioxidant status in dogs with poor semen quality: Three case studies.

Oxidative stress owing to an imbalance between reactive oxygen species and antioxidants, such as coenzyme Q10 (CoQ10), is a major contributor to male infertility. We investigated the effects of the reduced form of CoQ10 (ubiquinol) supplementation on semen quality in dogs with poor semen quality. Three dogs received 100 mg of ubiquinol orally once daily for 12 weeks. Semen quality, serum testosterone, and seminal plasma superoxide dismutase (SOD) activity were examined at 2-week intervals from 2 weeks before ubiquinol supplementation to 4 weeks after the treatment. Ubiquinol improved sperm motility, reduced morphologically abnormal sperm, and increased seminal plasma SOD activity; however, it had no effect on testosterone level, semen volume, and sperm number. Ubiquinol supplementation could be used as a non-endocrine therapy for infertile dogs.

Usefulness of addition of Orvus ES paste and sodium lauryl sulfate to frozen feline semen.

It has been shown that addition of the surfactant Orvus ES paste (OEP) and its main component sodium lauryl sulfate (SLS) to boar or dog semen before freezing improves post-thaw sperm motility and protects acrosome caps. In this study, we investigated the usefulness of the addition of OEP (0, 1, 2 and 4%) or SLS (0, 1, 2, 3 and 4 mg/ml) to cat ejaculates before freezing and their concentrations. Among the OEP addition groups, the 1% OEP group showed higher sperm motility than the other groups. Among the SLS addition groups, the 3 mg/ml SLS group showed slightly higher sperm motility and viability than the other groups. Comparison between the 1% OEP and 3 mg/ml SLS addition groups suggested a higher percentage of sperm with an acrosome cap in the 1% OEP group. The other sperm properties did not significantly differ between the 2 groups. These results indicate that addition of 1% OEP or 3 mg/ml SLS is effective for freezing of cat ejaculated semen.

The qualities of cryopreserved epididymal sperm collected from feline epididymides stored at low temperature.

We observed the influences of low-temperature storage of the feline epididymis on the epididymal semen qualities before and after cryopreservation to identify the optimal duration for low-temperature storage of the epididymis. After excision, the feline epididymis was stored at 4 degrees C for 0-72 hr and then subjected to epididymal sperm collection. When sperm from the refrigerated cauda epididymis were frozen and thawed, there was no significant difference in sperm motility between the 0- and 24-hr low-temperature storage groups, but sperm motility was significantly decreased in the 48-hr storage group. The above findings suggested that low-temperature storage of the epididymis until 24 hr is useful for frozen sperm collected from the feline cauda epididymis.

Changes in plasma testosterone level and semen quality after frequent injections of GnRH analogue in a Beagle dog with azoospermia.

A Beagle with a low plasma testosterone (T) level and azoospermia was given 10 subcutaneous injections of 1 microg gonadotropin-releasing hormone analogue (GnRH-A) per head at intervals of 3 days (Experiment 1), and 6 months after the final injection was given, 15 subcutaneous injections of 2 microg GnRH-A were given at intervals of 2 days (Experiment 2). The plasma T level increased and peaked at 8 weeks after the first injection of GnRH-A in both Experiment 1 and Experiment 2. Motile sperm were detected in the semen collected 8 weeks and 7 weeks after the first injection in Experiment 1 and Experiment 2, respectively. The total number of sperm peaked 9 weeks after the first injection in both Experiment 1 (4.5 x 10(6)) and Experiment 2 (72.8 x 10(6)).

Influence of the time between removal and cooling of the canine epididymis on post-thaw caudal epididymal sperm quality.

The effects of the time period between canine epididymis removal and cooling on post-thaw caudal epididymal sperm quality were investigated. Sperm recovered from the epididymis stored for 6 hr at 4 or 20 degrees C exhibited similar motility. However, when the epididymis was stored for 12 hr or longer at 20 degrees C, sperm motility was significantly lower than that at 4 degrees C (p<0.01). The post-thawed qualities of sperm recovered from the caudal epididymides that had been stored at 20 degrees C for 0 or 6 hr and then at 4 degrees C for 24 hr after removal were not significantly different. Therefore, leaving the canine epididymis at 20 degrees C for up to 6 hr after its removal may have little effect on the post-thaw quality of recovered caudal epididymal sperm.

Leydig cell tumor in an Amur tiger (Panthera tigris altaica).

A 14-year and 8-month-old intact male Amur tiger presented with an enlarged left testis, measuring 5.7 × 5.5 × 4.5 cm. The cut surface was mottled dark red to reddish brown in color. Microscopically, the enlarged left testis comprised round or polygonal neoplastic cells arranged in a diffuse sheet pattern. These neoplastic cells had a hyperchromatic nucleus and an abundant eosinophilic cytoplasm. Immunohistochemically, these neoplastic cells were positive for vimentin, chromogranin A, synaptophysin, melan-A, inhibin-α, and S100 and negative for desmin and WT-1. Based on these morphological and immunohistochemical findings, the tumor was diagnosed as a Leydig cell tumor.

Therapeutic effects of oral clomiphene citrate in 2 dogs with low plasma testosterone levels and poor semen quality.

Two dogs with low plasma testosterone (T) levels and poor semen quality were administered one tablet of 12.5 mg clomiphene citrate orally per day at 2-day intervals for 4 weeks. Plasma T levels, total sperm count, and sperm motility in both dogs temporarily increased between 3 and 6 weeks after the start of treatment. These results indicate that poor semen quality in dogs with low plasma T level can be improved by oral administration of clomiphene citrate.

Identification of the Histidine Residue in Vitamin D Receptor That Covalently Binds to Electrophilic Ligands.

We designed and synthesized vitamin D analogues with an electrophile as covalent modifiers for the vitamin D receptor (VDR). Novel vitamin D analogues 1-4 have an electrophilic enone group at the side chain for conjugate addition to His301 or His393 in the VDR. All compounds showed specific VDR-binding potency and agonistic activity. Covalent bond formations of 1-4 with the ligand-binding domain (LBD) of VDR were evaluated by electrospray ionization mass spectrometry. All compounds were shown to covalently bind to the VDR-LBD, and the abundance of VDR-LBD corresponding conjugate adducts of 1-4 increased with incubation time. Enone compounds 1 and 2 showed higher reactivity than the ene-ynone 3 and dienone 4 compounds. Furthermore, we successfully obtained cocrystals of VDR-LBD with analogues 1-4. X-ray crystallographic analysis showed a covalent bond with His301 in VDR-LBD. We successfully synthesized vitamin D analogues that form a covalent bond with VDR-LBD.

Testicular superoxide dismutase activity, heat shock protein 70 concentration and blood plasma inhibin-alpha concentration of dogs with a Sertoli cell tumor in a unilateral cryptorchid testis.

The proportions of Sertoli cell tumor (SCT), seminoma and Leydig cell tumor in 50 dogs with unilateral testicular tumors were 52%, 36% and 12%, respectively. The rate of occurrence of SCT in the cryptorchid testis was very high (71%). The testicular superoxide dismutase (SOD) activity, testicular heat shock protein (HSP) 70 concentration and peripheral blood plasma inhibin (INH)-alpha concentration of 10 dogs with a unilateral cryptorchid testis and no testicular tumors, 10 dogs with SCT in a unilateral cryptorchid testis and 10 normal dogs, all aged 5-15 years, were measured in order to identify high risk factors for the occurrence of SCT in the canine cryptorchid testis. The mean SOD activity in cryptorchid testes and SCTs was significantly lower and higher, respectively, than in normal testes (both P<0.01). The mean HSP 70 concentration in both cryptorchid testes and SCTs was significantly higher than in normal testes (both P<0.01). The mean plasma INH-alpha concentration of the cryptorchid and SCT dogs was significantly lower and higher, respectively, than in normal dogs (P<0.05 and 0.01, respectively). The low SOD activity in the cryptorchid testis, low blood plasma INH-alpha concentration of the cryptorchid dogs and high HSP 70 concentration in the SCTs may be related to the occurrence of SCT and tumor cell proliferation in canine cryptorchid testes.

Changes in the plasma testosterone level and testicular superoxide dismutase activity of 5 azoospermic beagles after GnRH analogue injections.

The peripheral blood plasma testosterone (T) levels and superoxide dismutase (SOD) activity were measured in 5 azoospermic (AZ-) beagles. The mean values in the AZ-dogs were significantly lower than in 7 control beagles (P<0.001). Subcutaneous injections of 1 mug/kg GnRH analogue three times weekly in the AZ-dogs induced significant increases in mean T level and SOD activity (P<0.05) and improvement in spermatogenesis. Thus, spermatogenic function in the dog appears to be maintained by T and normal SOD activity in the testis.

Superoxide dismutase and catalase activities in the seminal plasma of normozoospermic and asthenozoospermic Beagles.

We measured the blood plasma testosterone (T) levels and superoxide dismutase (SOD) and catalase activities in the seminal plasma of the ejaculates of 5 normal (2-5 years old) and 5 asthenozoospermic (AZ-) (3-5 years old) Beagles. Sperm ejaculated by AZ-dogs was incubated for 3 hr in Eagle's MEM only (controls) or Eagle's MEM containing 100 units/ml of SOD or catalase. Sperm motility was examined during incubation. The mean (+/- SE) plasma T level of the AZ-dogs (1.2 +/- 0.2 ng/ml) was significantly lower than in the normal dogs (2.5 +/- 0.2 ng/ml) (P<0.005). The mean (+/- SE) seminal plasma SOD and catalase activities (18.8 +/- 1.9 and 0.5 +/- 0.1 unit/g protein, respectively) were significantly lower in the AZ-dogs than in the normal dog (43.3 +/- 2.5 and 2.2 +/- 0.4 unit/g protein, respectively) (P<0.001 and 0.01, respectively). The motility of sperm incubated in Eagle's MEM containing SOD or catalase was significantly higher than that of control sperm incubated in only Eagle's MEM after 2 or 3 hr of incubation (P<0.05). The results of this study indicate that poor T secretion by the testes and low antioxidant enzyme activities are related to AZ in the dog.

Intrauterine insemination with fresh semen in Amur leopard cat (Pionailurus bengalensis eutilura) during non-breeding season.

Equine and human chorionic gonadotropins were administered to two female Amur leopard cats to induce estrus and ovulation during non-breeding season. Fresh semen collected from male cats was surgically inseminated into the uterine horn of the females. In one animal, two fetal sacs without heartbeats were observed on abdominal ultrasonography 31 days after insemination, which indicated that embryo death had occurred. In the other animal, fetal heartbeats were detected in two fetal sacs 29 days after insemination, which confirmed as pregnancy. This animal delivered two newborns 68 days after insemination; the one of the kittens was assumed to be stillbirth, and the other grew normally. In this study, we successfully obtained a kitten from an Amur leopard cat by artificial breeding for the first time in Japan.

MicroRNA expression profiling in canine prostate cancer.

Canine prostate cancer (cPCa) is an untreatable malignant neoplasm resulting in local tissue invasion and distant metastasis. MicroRNAs (miRs) are small non-coding RNAs that function as oncogenes or tumor suppressors. The purpose of this study was to characterize the expression of miRs that are altered in cPCa tissue. The expression levels of 277 mature miRs in prostatic tissue (n=5, respectively) were compared between the non-tumor and tumor groups using real-time PCR. Five miRs (miR-18a, 95, 221, 222 and 330) were up-regulated, but 14 miRs (miR-127, 148a, 205, 299, 329b, 335, 376a, 376c, 379, 380, 381, 411, 487b and 495) were down-regulated specifically in cPCa (P<0.05). These miRs have potential use as early diagnosis markers for cPCa and in miR-based therapy.

Intrauterine transfer of early canine embryos.

The success rate of in vitro fertilization (IVF) in dogs is low and only early embryos have been obtained. In the present study, we investigated the use of intrauterine transfer of early-stage canine embryos to obtain pups. Twenty-three female dogs, in which the date of ovulation (based on plasma progesterone concentrations) differed by +/-1 day, were used (10 donors and 13 recipients). The uterine tube was extirpated under general anesthesia 1-4 days after mating (5-7 days after ovulation), and descending perfusion was done to collect embryos. Embryos were examined and transferred into the uterine horn of a recipient, ipsilateral to the ovary with the most corpora lutea. Pregnancy was established in one of eight bitches that received early embryos (zygote to 4-cell embryos); she received two zygotes and one 2-cell embryo and delivered two puppies. Although intrauterine transfer of early embryos (zygote to 4-cell embryos) was difficult, pregnancy was achieved, suggesting that uterine tube transfer is appropriate for these early-stage embryos.