Therapeutic Ultrasound as a Potential Male Dog Contraceptive: Determination of the Most Effective Application Protocol

Effect of direct therapeutic ultrasound exposure of ovaries on histopathology, inflammatory response, and oxidative stress in dogs

BACKGROUND

This research was designed to evaluate the effects of therapeutic ultrasound waves on ovarian germinal tissue and inflammatory cytokines (interleukin-6 (IL-6), IL1β, tumor necrosis factor-α (TNF-α)), acute phase proteins (serum amyloid A (SAA), C reactive protein (CRP)) and oxidative stress (total antioxidant capacity (TAC), and malondialdehyde (MDA)) in dogs. Twenty-six clinically healthy adult mix-breed female dogs were aligned into three groups. Laparotomy was performed in control (n = 6) and treatment (T5, n = 10; T10, n = 10) groups. The ultrasonic exposure of ovaries in treatment groups was performed during laparotomy by round motions of the therapeutic ultrasonic transducer on both ovaries (1 MHz frequency, 1.5 W⁄cm2) for 5 min in the T5 group and for 10 min in the T10 group. Blood samples were collected from the jugular vein into a plain glass tube on days 0 (before laparotomy), 3, 6, and 9 after surgery. All control and treatment groups' dogs were ovariectomized for histological evaluation on day 60 after laparotomy or laparotomy + ultrasound exposure.

RESULTS

Direct exposure of ovaries with therapeutic ultrasound waves induced inflammation and oxidative stress comparison with the control group. Histopathological evaluation of treated ovaries with ultrasound waves indicated a decreased number of primordial follicles (ovarian reserve) and oocyte preservation scores compared with ovaries in the control group.

CONCLUSIONS

These changes may cause subfertility in the long term. It seems that inflammatory response and oxidative stress are factors in the permanent damage of ovarian tissue.

Effects of therapeutic ultrasound and moderate heat on stallion testes

Transplantation of stem cells into dysfunctional testes is currently being investigated as a therapeutic option for men and stallions with advanced testicular degeneration. This series of "proof of concept" studies aimed to identify a safe and efficient method of inducing severe testicular degeneration to create an optimal equine recipient model for intratesticular stem cell transplantation (SCT). Two ex vivo and two in vivo experiments were conducted. At first, forty testes obtained from castrations were used to identify an effective therapeutic ultrasound (TUS) device and the protocol for increasing intratesticular temperature in stallions. Six min of treatment using the Vetrison Clinic Portable TUS machine raised the intratesticular temperature by 8°C-12.5 °C. This protocol was applied to treat three scrotal testes in three Miniature horse stallions, three times, every other day. Contralateral testes served as controls. There were signs of slight tubular degeneration in treated testes two and three weeks after TUS treatment. The number of seminiferous tubules (STs) with exfoliated germ cells (GCs) was increased in one testis only, three weeks after treatment. The degree of apoptosis of GCs was higher in each treated testis in comparison to the contralateral control testis. Next, the ability of various heating devices to increase intratesticular temperatures to at least 43 °C in stallion testes was tested, using twenty testes obtained from castrations. ThermaCare® Lower Back & Hip Pain Therapy Heatwrap (TC heat wrap) reliably increased intratesticular temperatures and kept them continuously between 43 °C and 48 °C for seven to 8 h. In the follow-up in vivo study, the left testes of three Miniature horse stallions were treated with TUS, after which both testes of each stallion were treated with moderate heat provided by the TC heat wrap (three times, every other day, for 5 h each time). There were signs of moderate tubular degeneration in the samples from all treated testes obtained three weeks after treatments (Heat only or Heat/TUS): areas with hypospermatogenesis, spermatogenic arrest, vacuolized Sertoli cells, numerous STs with exfoliated GCs, increased degree of GCs apoptosis, and changes in three histomorphometric numeric attributes of STs. We concluded that TUS or TC wraps increase intratesticular temperature of the isolated stallion testes. Further, treatment with TUS or moderate heat may induce mild to moderate degenerative changes in stallion testes. However, to achieve more robust result - severe testicular degeneration, our treatment protocol has to be modified.

Systematic Review of Complementary and Alternative Veterinary Medicine in Sport and Companion Animals: Therapeutic Ultrasound

BACKGROUND

To explore the scientific evidence for therapeutic ultrasound (TU), we conducted a systematic review of the literature on TU in dogs, horses, donkeys, and cats.

METHODS

In three major databases, relevant articles published in 1980-2020 were identified. The risk of bias in each article was evaluated.

RESULTS

Twenty-four relevant articles on the effects of TU in dogs, nine in horses, two in donkeys, and one in cats were identified. TU usually involved 2-6 treatments weekly for up to 4 weeks. Articles on tendon, ligament, and bone healing, acute aseptic arthritis, osteoarthritis, paraparesis, hindquarter weakness, and back muscle pain were identified. In experimental bone lesions in dogs, there is moderate scientific evidence for enhanced healing. For the treatment of other musculoskeletal conditions, the scientific evidence is insufficient due to the high risk of bias. There is substantial evidence that continuous TU increases tissue temperature in muscles and tendons by up to 5 °C in healthy animals. For disorders in tendons, ligaments, muscles, and joints in sport and companion animals, there is insufficient evidence for the clinical effects of TU.

A High Intensity Focused Ultrasound System for Veterinary Oncology Applications

Background

Magnetic resonance-guided focused ultrasound surgery is an incisionless energy-based thermal method that is used for ablating tumors in the veterinary clinic.

Aims and Objectives

In this article we describe a prototype of a veterinary system compatible with magnetic resonance imaging intended for small-to-medium-sized companion animals that was developed and tested in vivo in adult rabbits.

Methods

Real-time monitoring of the ablation during the experiment was possible with MR thermometry. Experiments involved thermal monitoring of sonications applied in the thigh of the rabbits. A 38-mm diameter transducer operating at 2.6 MHz was used with a 60-mm-focal length. The robotic system employed 3 linear axes and one angular axis. For this study, only X and Y axis were enabled. Due to the target size limitations, motion in Z and Θ was not needed. The functionality of the positioning device was evaluated by means of MR thermometry, demonstrating sufficient heating and accurate motion in both axes of operation.

Results

The postmortem findings confirm the ability of the system to induce thermal ablations in vivo in the absence of adverse effects.

Conclusions

The device is a reliable and affordable solution for companion animal hospitals, offering and additional tool for the veterinary oncology society.

New Prospects in Neutering Male Animals Using Magnetic Nanoparticle Hyperthermia

Controlling populations of free-roaming dogs and cats poses a huge challenge worldwide. Non-surgical neutering strategies for male animals have been long pursued, but the implementation of the procedures developed has remained limited to date. As submitting the testes to high temperatures impairs spermatogenesis, the present study investigated localized application of magnetic nanoparticle hyperthermia (MNH) to the testicles as a potential non-surgical sterilization method for animals. An intratesticular injection of a magnetic fluid composed of manganese-ferrite nanoparticles functionalized with citrate was administered followed by testicle exposure to an alternate magnetic field to generate localized heat. Testicular MNH was highly effective, causing progressive seminiferous tubule degeneration followed by substitution of the parenchyma with stromal tissue and gonadal atrophy, suggesting an irreversible process with few side effects to general animal health.

A preliminary study of transabdominal ultrasonic wave treatment on the germinal tissues of dog ovaries as a contraceptive approach

The aim of this study was to investigate effects in dogs of ultrasonic waves on the ovarian germinal tissues. There was assignment of ovaries of each dog being a control (right ovary) or treated (left ovary) tissue, regardless of the estrous cycle status. For the treated ovary, the ultrasonic probe was set at a frequency of 1 MHz and power of 1.5 W/cm² and placed on the skin at a location in close proximity to the left ovary that was predetermined using ultrasonography. Subsequently there was a focusing of the waves for 5 min on the tissues of the treated ovary. The treatment was repeated three times at 48 -h intervals. There was placement of the probe at the same proximity to the control ovary; however, the probe was not activated. Ovariectomies for histological examination were performed 30 (five dogs) and 60 (five dogs) days following the ultrasonic treatments. Histopathological examination results indicated there was a reduction in numbers of primordial follicles of four dogs and oocyte degeneration in the Graafian and primordial follicles of five dogs. In most dogs, the degeneration of the granulosa cells of the Graafian follicle was observed in the treated ovaries. The results indicate the treatment of ovaries with transabdominal ultrasonic waves at a 1 MHz frequency, and 1.5 W/cm² power for three times with each treatment lasting for 5 min at a 48-h interval, did not result in complete ablation of the germinal tissues of the ovary during the 2-month period subsequent to treatment.

The effects of therapeutic ultrasound waves on testicular tissue, echogenicity, semen quality, oxidative stress, and acute-phase proteins in dogs

The application of high-intensity ultrasound waves has been investigated as one of the non-invasive methods of contraception in several species. This study was aimed to investigate the mechanism of contraception in dogs using ultrasound waves by measuring acute-phase proteins and oxidative stress indices. Ten mixed-breed adult and fertile dogs were divided into two equal treatment and control groups. The dogs' testes in the treatment group were exposed to ultrasound waves at an intensity of 1.5 W/cm² and a frequency of 1 MHz, 3 times for 5 min, and every 48 h. Blood sampling (before exposure, and 3, 5, 7, 21, 35, 49, and 63 days after exposure), semen collection (before exposure, and 4, 6, and 8 weeks after exposure), testicular ultrasonography (before exposure, and 4, 6, and 8 weeks after exposure), and testis histopathology (30 and 60 days after exposure) were performed during the study. The echogenicity of the dogs' testes significantly increased in the treatment group from week 6 onwards (P = 0.001). The concentration and progressive motility of spermatozoa in all samples, from both the control and the treatment groups, were normal at different times during the study. There was no significant change in the concentration of serum testosterone. The activity of superoxide dismutase and glutathione peroxidase enzymes on days 3, 5, and 7 and catalase activity on day 3 significantly decreased in the treatment group compared to those of the control group (P = 0.006). In addition, malondialdehyde concentration significantly increased in the treatment group on days 3, 5, and 7 (P < 0.0001). The concentrations of C-reactive protein, serum amyloid A, and alpha-1-acid glycoprotein significantly increased on days 3, 5, and 7 compared to those of the control group (P = 0.005). To sum up, high-intensity ultrasound waves could activate the process of the acute phase response of inflammation and oxidative stress and induce further damage to the testicular tissue in dogs. This was mainly observed in the first week after the testes were exposed to ultrasound waves.

Desexing Dogs: A Review of the Current Literature

Background: Desexing dogs is promoted for population control, preventative healthcare, and behavior modification. Common methods are orchiectomy and ovariectomy/ovariohysterectomy. GnRH superagonist implants are available in some areas. Alternative methods like vasectomy and salpingectomy/hysterectomy are uncommon. The terminology used to describe desexing is inconsistent and contradictory, showing a need for the adaption of standardized terminology. Population Control: Surprisingly, empirical studies show no effects of desexing on population control in companion and shelter dogs despite desexing being consistently recommended in the literature. There is evidence for a population control effect in free-roaming dogs, where desexing also has benefits on zoonotic disease and bite risk. Population control in free-roaming dogs is mostly correlated with female, not male desexing. Health and Lifespan: Desexing affects numerous disease risks, but studies commonly neglect age at diagnosis and overall lifespan, age being by far the most important risk factor for most diseases. We argue that lifespan is a more important outcome than ultimate cause of death. A beneficial effect of desexing on lifespan is consistently demonstrated in females, while evidence for a beneficial effect in males is inconsistent. Studies are likely biased in desexing being a proxy for better care and desexed dogs having already lived to the age of desexing. Desexing reduces or eliminates common life-limiting diseases of the female reproductive system such as pyometra and mammary tumors, while no analogous effect exists in males. Disease risks increases across sexes and breeds include cruciate ligament rupture, various cancers, and obesity. Urinary incontinence risk is increased in females only. Various other disease risk changes show considerable variability between breeds and sexes. Behavioral Effects: Desexed males show reduced libido, roaming, conspecific mounting, and urinary marking frequency, as well as reduced male dog-directed aggression in a majority of males desexed for behavioral reasons. There is a detrimental effect on the risk and progression of age-related cognitive dysfunction. Desexed dogs may be less likely to cause bite injuries across sexes. The evidence for other effects such as human-directed aggression, human or object mounting, resource guarding, or shyness and anxiety is inconsistent and contradictory. There are few studies specific to females or individual breeds. Conclusions: The evidence for a beneficial effect of desexing is stronger in female than in male dogs; however, there is significant variation between breeds and sexes, and more research is needed to further elucidate these differences and to arrive at individualized evidence-based recommendations for clinical practice.