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CASE REPORT
published: 13 October 2021
doi: 10.3389/fvets.2021.750019
Frontiers in Veterinary Science | www.frontiersin.org 1October 2021 | Volume 8 | Article 750019
Edited by:
Marcelo Horacio Miragaya,
University of Buenos Aires, Argentina
Reviewed by:
Maria Alejandra Stornelli,
National University of La
Plata, Argentina
Izhar Hyder Qazi,
Shaheed Benazir Bhutto University of
Veterinary & Animal
Sciences, Pakistan
*Correspondence:
Min Jung Kim
mjbiogen@gmail.com
Specialty section:
This article was submitted to
Animal Reproduction -
Theriogenology,
a section of the journal
Frontiers in Veterinary Science
Received: 30 July 2021
Accepted: 13 September 2021
Published: 13 October 2021
Citation:
Mahiddine FY and Kim MJ (2021)
Case Report: Orchiopexy in Two
Poodle Dogs and Its Effect on Their
Sperm Quality Parameters.
Front. Vet. Sci. 8:750019.
doi: 10.3389/fvets.2021.750019
Case Report: Orchiopexy in Two
Poodle Dogs and Its Effect on Their
Sperm Quality Parameters
Feriel Yasmine Mahiddine and Min Jung Kim*
Department of Research and Development, Mjbiogen Corp., Seoul, South Korea
Cryptorchidism is a common congenital abnormality encountered in veterinary clinics.
The treatment of choice for this condition is a surgical procedure named orchiectomy or
orchidectomy, where the retained testicle is removed. Surgical placement and fixation of
the cryptorchid testicle into the scrotum, referred to as orchiopexy, is used in humans.
However, due to the hereditary nature of cryptorchidism in dogs, this treatment option
has not been proposed in veterinary clinics. Two adult Poodle dogs were referred to our
research facility for a sperm parameter evaluation check. The two dogs were unilateral
cryptorchid dogs treated with orchiopexy before the age of 6 months. Their sperm
kinematics and morphology were within normal ranges, and their libido and testicles sizes
were normal. Treatment of unilateral cryptorchidism by orchiopexy in dogs before the age
of 6 months successfully restored spermatogenic function and sperm quality-related
parameters. However, due to the nature of this condition, orchiectomy remains the
treatment of choice.
Keywords: cryptorchidism, orchiopexy, dog, orchiectomy, sperm
INTRODUCTION
Cryptorchidism is a congenital urological condition characterized by incomplete or absent
testicular descent. In dogs, the testicles pass through the inguinal canal 3–4 days after birth
and reach their final position in the scrotum on day 35 of life (1). Abnormal abdominal
translocation and transinguinal migration result from incomplete or absent testicular descent due
to abnormalities in the gubernaculum’s outgrowth and regression or the persistence of cranial
gonadal suspensory ligaments (1,2). Different forms of cryptorchidism have been described based
on whether one or both testicles are involved and where their position is (1,3). Depending on the
side, cryptorchidism can be bilateral or unilateral (1). The latter form is the most common (75%
of the cases), with the right testicle being twice as likely to be retained (4,5). Depending on the
position, high abdominal, low abdominal, or inguinal cryptorchid testicles are the different forms
that can be found (4,6).
It is commonly encountered in small animal veterinary clinics, with an incidence of 1.2–12.9%
in dogs (4,5) and 1.7–3.8% in cats (4,5). In dogs, it is an inherited, autosomal recessive trait, with a
higher incidence reported in small breeds than in large breeds (5), especially in breeds such as Boxer,
Cairn Terrier, Chihuahua, English Bulldog, Maltese, Miniature Poodle, Miniature Schnauze, Old
English Sheepdog, Pekingese, Pomeranian, Shetland Sheepdog, and Toy Poodle (7). In general, a
higher incidence of cryptorchidism in purebred dogs than in crossbred dogs has been reported (8).
Mahiddine and Kim Orchiopexy Effects on Sperm Parameters
The treatment of cryptorchidism by orchiopexy in dogs is
a controversial topic, as cryptorchidism is a hereditary trait,
and the risks of testicular neoplasia are still present in these
animals (9). This surgery is no longer performed in veterinary
hospitals, and cryptorchid dogs should not be included in
reproductive programs. Although the treatment of choice for
cryptorchidism is orchiectomy, we recently encountered two
cases of orchiopexy performed in a private clinic. Kawakami et al.
(10) reported that spermatogenesis was preserved after surgery
in young dogs (10). However, no studies have been conducted
on canine sperm morphology and kinematic parameters after
orchiopexy. In this case report, we evaluated the morphological
and kinematic parameters of sperm from two dogs who had
undergone orchiopexy surgery.
CASE PRESENTATION
Two unilateral cryptorchidic Toy Poodle dogs that underwent
orchiopexy were referred to our research facility (Mjbiogen) in
Seoul, South Korea, for the evaluation of their sperm kinematic
and morphological parameters. Orchiopexy was performed at 2
months of age in a private clinic 2 years ago. No information
about the surgical procedure or the location of the cryptorchid
testicles was disclosed, and the owners gave their approval for the
use of these results for publication. After reaching puberty, the
owners reported successful pregnancies and delivery of healthy
offsprings, using semen from these dogs. To assess the effects of
the surgery on sperm quality, we collected semen from these dogs
(n=2), analyzed the sperm quality parameters, and compared
them with those of normal, age-matched toy poodles (n=3)
from the same owner. Statistical analysis was performed using
GraphPad Prism 5.0 (GraphPad, CA, San Diego, USA), and
data were analyzed using one-way analysis of variance (ANOVA)
following by a Tukey’s multiple comparison test. All dogs were
fed commercial adult dry food, and water was provided ad
libitum. Semen was obtained by digital manipulation in the
presence of a bitch in estrus, and only the second fraction of
the ejaculate was collected and processed for evaluation in the
laboratory. During collection, libido in the operated dogs was not
diminished nor lower than that of the control dogs. To assess any
difference in the testicles sizes, the lengths of the longitudinal and
transverse axes of the right and left testicles were measured using
a simple measuring flat ruler. The results for each testicle were
transcribed into a table, and the orchiopexy and normal testicles
were compared (Table 1). At palpation, the operated testicle had
TABLE 1 | Lengths of the longitudinal and transverse axes of the right and left testicles in orchiopexy and control dogs.
Parameters Orchiopexy dog 1 Orchiopexy dog 2 Control dogs
Right longitudinal axis (cm) 1.9 2 2.4 ±0.1
Left longitudinal axis (cm) 2.4 3 2.7 ±0.1
Right transverse axis (cm) 1.1 1.3 1.4 ±0.1
Left transverse axis (cm) 1.3 1.2 1.5 ±0.1
no deformation, but in one of the dogs the right testicle was
slightly smaller than the left testicle (Orchiopexy dog 1).
Each collected semen sample (n=3) was diluted with
Tris-extender (1:1 [v/v]—distilled water, Tris (hydroxymethyl)
aminomethane 24 g/L, citric acid 14 g/L, fructose 8 g/L, and
kanamycin sulfate 0.15 g/L; pH 6.6, 290 mOsm) and centrifuged
at 700 ×gfor 1 min. The supernatant was collected and
centrifuged (500 ×g/5 min), and only the pellet was resuspended
in Tris-extender to achieve a concentration of 200 ×106
sperm/ml. Transportation media−54% (v/v) Tris-extender, 40%
(v/v) egg yolk, and 6% (v/v) glycerol—was added, and the
samples were stored at 4◦C to be transported to the laboratory,
1 h away from the breeding facility. Once in the laboratory,
each sample was washed and resuspended in Tris-extender
before proceeding for further analysis. The sperm quality-related
parameters assessed were motility and kinematic parameters,
viability, and morphology parameters, using a computer-assisted
sperm analysis (CASA; Sperm Class Analyzer R
System version
6.4.0.93, Microptic, Barcelona, Spain). The system included a
Nikon Eclipse ci-L microscope (Nikon, Tokyo, Japan) with a
×10 phase-contrast objective. Leja 20-µm chamber slides (Leja,
Gynotec Malden, Nieuw Vennep, the Netherlands) were used
for the analysis, and the frame rate was set at 25 frames/s.
Sperm motility, progressive motility, curvilinear velocity (VCL),
straight-line velocity (VSL), average path velocity (VAP), linearity
(LIN), straightness (VSL/VAP) (STR), wobble VAP/VCL (WOB),
the amplitude of lateral head, and beat cross frequency were
analyzed (Table 2). No differences were observed between the
orchiopexy dogs and the control dogs, indicating that dogs that
underwent orchiopexy surgery have sperm kinematic parameters
within the normal ranges.
Eosin Y staining was used to determine the percentage of
live sperm cells. In brief, the samples were washed, and a
drop of 10 µlfrom the sperm pellet with an equal amount
of 0.5% eosin Y solution was mixed and smeared onto
warm glass slides. The slides were then air-dried, and the
sperm were evaluated. For each stained smear, 200 sperm
were examined with a light microscope (Eclipse Ts 2, Nikon,
Tokyo, Japan) with an oil immersion objective lens (×1000
magnification) (11). The unstained sperm were counted as
alive, and the stained sperm were counted as dead cells. The
results are expressed as the percentage of live sperm cells
(12) (Table 2) and showed no difference between orchiopexy
dogs and control dogs. The sperm acrosome membrane was
analyzed using fluorescein isothiocyanate-conjugated peanut
agglutinin (FITC-PNA), as previously described (13). In brief,
Frontiers in Veterinary Science | www.frontiersin.org 2October 2021 | Volume 8 | Article 750019
Mahiddine and Kim Orchiopexy Effects on Sperm Parameters
TABLE 2 | Kinematic parameters, live cell, and intact acrosome percentages in orchiopexy and control dogs.
Parameters Orchiopexy dog 1 Orchiopexy dog 2 Control dogs
Concentration (M/ml) 355.1 ±167.7 577.1 ±51.9 592.6 ±71.9
Semen volume (ml) 1.8 ±0.4 1.5 ±0.1 0.7 ±0.1
Motility (%) 89.7 ±5.3 99.1 ±0.5 96.8 ±1.4
Progressive motility (%) 49.8 ±9.8 61.4 ±2.4 54.6 ±6.8
VCL (µm/s) 80.5 ±12.9 119.8 ±3.5 103.0 ±9.6
VAP (µm/s) 49.6 ±6.5 64.5 ±1.4 58.9 ±5.5
VSL (µm/s) 34.7 ±3.0 39.6 ±2.4 37.1 ±3.5
LIN (%) 42.2 ±4.7 31.8 ±1.1 34.8 ±1.9
STR (%) 66.2 ±5.6 57.6 ±1.9 59.0 ±2.6
WOB (%) 61.2 ±1.9 53.7 ±0.5 57.2 ±0.9
ALH (µm) 2.1 ±0.4 3.1 ±0.1 2.7 ±0.2
BCF (Hz) 10.4 ±1.1 10.5 ±1.0 10.8 ±0.8
Live cell percentage (%) 75.3 ±8.0 76.8 ±2.5 72.9 ±3.8
Intact acrosome (%) 89.7 ±4.4 93.5 ±3.0 94.6 ±1.1
VCL, curvilinear velocity; VAP, average path velocity; VSL, straight-line velocity; LIN, linearity; STR, straightness (VSL/VAP); WOB, wobble (VAP/VCL); ALH, amplitude of lateral head
displacement; BCF, beat cross frequency.
semen was smeared on glass slides, air-dried, fixed in absolute
methanol, stained, and mounted with anti-fade mounting
medium (VECTASHIELD R
, Vector Laboratories, Burlingame,
CA, USA). The integrity of the sperm acrosome membrane was
analyzed using an epifluorescence phase-contrast microscope
(Eclipse Ts 2, Nikon, Tokyo, Japan) and classified as intact
acrosome (strong green fluorescence) or non-intact acrosome
(partial or no fluorescence) (14) (Table 2 and Figure 1).
Our results showed that acrosome integrity was preserved
in orchiopexy dogs. Diff-Quick staining was used to assess
morphological defects. Each sample was washed and smeared
onto warm glass slides, fixed in methanol, and stained with
eosin as an anionic/acidic dye and with methylene blue as
a cationic dye. The slides were air-dried, and morphology
was assessed using a light microscope (Eclipse Ts 2, Nikon,
Tokyo, Japan) with an oil immersion objective lens (×1,000
magnification). Head defects, droplet, coiled, and bent tail defects
were evaluated in each sample (15) (Table 3). Morphology
parameters were similar in orchiopexy and control dogs,
which shows that orchiopexy at a young age in dogs has no
negative effects on sperm morphology and that spermiogenesis
is preserved.
DISCUSSION
An orchiopexy is the surgical fixation of testicles in the scrotum
(16). It can be performed through open surgery techniques or
laparoscopy (17). The incidence of undescended testis (UDT)
in humans is 1% in male infants, and it is considered as one
of the most common congenital abnormalities in males (18).
However, unlike cryptorchidism in dogs, UDT is corrected with
orchiopexy. The hereditary character of cryptorchidism in dogs
makes it hard, and almost unethical, to perform this surgery
on cryptorchid males (8,19). Moreover, cryptorchidism can be
associated with other congenital abnormalities (8,20), and the
FIGURE 1 | Sperm acrosome stained with fluorescein
isothiocyanate-conjugated peanut agglutinin (FITC-PNA). Sperm with (A) intact
acrosome and (B) non-intact acrosome.
risks of developing a neoplasia in testicles subjected to orchiopexy
are higher (6,9). The aim of this case study is to assess the
sperm parameters in two cryptorchid dogs; however, for all the
aforementioned reasons, orchiopexy should not be suggested by
practicians to cryptorchid dogs owners.
In humans, early orchiopexy (<1 year old) was associated with
significantly higher sperm count and motile sperm in comparison
with cases where orchiopexy was performed later (1–2 years of
age) (21). As orchiopexy is a controversial surgery in veterinary
medicine, the ideal age to perform this surgery has never been
established. In dogs, the final diagnosis of cryptorchidism can
only be made after 6 months of age (22). However, since testicles
Frontiers in Veterinary Science | www.frontiersin.org 3October 2021 | Volume 8 | Article 750019
Mahiddine and Kim Orchiopexy Effects on Sperm Parameters
TABLE 3 | Percentage of morphological defects in orchiopexy and control dogs.
Parameter Orchiopexy dog 1 Orchiopexy dog 2 Control dogs
Morphological defects 2.5 ±1.3 1.0 ±0.3 2.2 ±1.0
are expected to reach their final position around day 35 of life
(23), cryptorchidism can be suspected in pups aged ≥2 months.
In this case, according to the owners, orchiopexy was
performed on the two Poodle dogs at 2 months of age to ensure a
higher percentage of full recovery of spermatogenetic function.
When the testicles stay in the abdominal cavity, where the
temperature is higher, spermatogenesis is compromised. Since
testicles’ sensitivity to temperature is high, a surgery performed
later could result in the absence of spermatogenesis or the
presence of poor quality sperm with low fertilizing ability (24).
From our own data, a beagle dog with unilateral cryptorchidism
showed motility and progressive motility parameters of 24.7
±29.4% and 29.8 ±22.3%, respectively (unpublished data),
which shows that the sperm kinematic parameters of unilateral
cryptorchid dogs are lower than those of normal dogs.
In humans, males who underwent unilateral orchiopexy at
a young age (before 8 years of age) have a good prognosis for
fertility compared to males who were operated on later or for
both testicles (25). In this case, dogs who underwent unilateral
orchiopexy before the age of 6 months had sperm kinematic and
morphological parameters within the normal range. It should
be noted that Orchiopexy dog 2 sperm parameters, especially
sperm total motility and progressive motility, were slightly higher
than those of the other dogs but were not statistically significant
(p-value >0.05). Morphological defects in Orchiopexy dog 2
sperm samples were also lower than those of the control dogs
and Orchiopexy dog 1 (Table 3). In addition, Orchiopexy dog
1 sperm concentration and acrosome integrity were lower than
those of control dogs and Orchiopexy dog 2, without statistical
significance (p-value >0.05) (Table 2). This difference in sperm
concentration between Orchiopexy dog 1 and the other dogs
could also be attributed to the difference in testicular sizes
(Table 1) (26). From these results, unilateral cryptorchid dogs
treated with early orchiopexy may have a good prognosis for
fertility, and their sperm quality parameters are similar to those
of fertile control dogs.
CONCLUSION
Here, we report two cases of dog orchiopexy in which the
sperm kinematic and morphological parameters were similar to
those from healthy age-matched dogs of the same breed. Like in
humans, orchiopexy at a young age in dogs seems to preserve
sperm quality parameters as our results show that orchiopexy
before the age of 6 months did not alter sperm quality parameters
in these two dogs. This makes dogs as one potential orchiopexy
study model for humans. However, this remains a controversial
surgery due to the hereditary aspect of cryptorchidism and the
risk of testicular neoplasia. The results from this case study
should not encourage dog owners or practitioners to perform it.
Therefore, we recommend veterinarians to warn owners about
this surgery and its dangers and dissuade them from considering
it as a treatment option.
DATA AVAILABILITY STATEMENT
The original contributions presented in the study are included
in the article/supplementary material, further inquiries can be
directed to the corresponding author/s.
ETHICS STATEMENT
Ethical review and approval was not required for the animal study
because it is a clinical case and the owners gave their permission.
Written informed consent was obtained from the owners for the
participation of their animals in this study.
AUTHOR CONTRIBUTIONS
MK participated in collecting owners approval, semen samples,
and revising the manuscript. FM participated in collecting semen
samples and results and drafting and revising the manuscript.
Both authors contributed to the article and approved the
submitted version.
FUNDING
Cooperative research program of Rural Development
Administration (#PJ014786012021).
ACKNOWLEDGMENTS
The authors would like to thank Hee Kee Park for his help
and assistance.
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Conflict of Interest: The authors were employed by company Mjbiogen Corp.
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