Evaluation of chemical castration with calcium chloride versus surgical castration in donkeys: testosterone as an endpoint marker

Male animal sterilization: history, current practices, and potential methods for replacing castration

Sterilization and castration have been synonyms for thousands of years. Making an animal sterile meant to render them incapable of producing offspring. Castration or the physical removal of the testes was discovered to be the most simple but reliable method for managing reproduction and sexual behavior in the male. Today, there continues to be global utilization of castration in domestic animals. More than six hundred million pigs are castrated every year, and surgical removal of testes in dogs and cats is a routine practice in veterinary medicine. However, modern biological research has extended the meaning of sterilization to include methods that spare testis removal and involve a variety of options, from chemical castration and immunocastration to various methods of vasectomy. This review begins with the history of sterilization, showing a direct link between its practice in man and animals. Then, it traces the evolution of concepts for inducing sterility, where research has overlapped with basic studies of reproductive hormones and the discovery of testicular toxicants, some of which serve as sterilizing agents in rodent pests. Finally, the most recent efforts to use the immune system and gene editing to block hormonal stimulation of testis function are discussed. As we respond to the crisis of animal overpopulation and strive for better animal welfare, these novel methods provide optimism for replacing surgical castration in some species.

Effects of intratesticular injection of hypertonic mannitol and saline on the quality of donkey sperm, indicators of oxidative stress and testicular tissue pathology

OBJECTIVES

The aim of the present study was to examine donkey sperm quality after intratesticular injection of hypertonic mannitol (HM) and saline (HS).

METHODS

Randomly assigned to five treatment groups were 15 adult male donkeys: (1) Control group (no treatment), (2) Surgery group (surgical castration for testosterone control), (3) NS group (normal saline intratesticular injection), (4) HS group (hypertonic saline), and (5) HM group. We injected 20 mL per testicle. We took 5 mL blood from all donkeys before injection. Castration was performed under general anesthesia 60 days later. Samples included blood and testicular tissue. Total motility (TM), progressive motility (PM), movementy features, DNA damage, morphology, viability, and plasma membrane functionality were evaluated. Hormone analyses, histomorphometric studies and oxidative stress indices including total antioxidant capacity (TAC), glutathione peroxidase (GPx), glutathione (GSH), superoxide dismutase (SOD), malondialdehyde (MDA), and NADP+/NADPH were evaluated. Apoptosis, pyroptosis-related Bax, Caspase-1, GSDMD, and Bcl-2 expression were also assessed.

RESULTS

In HS and HM groups, testosterone, epididymal sperm count, motility, viability, and plasma membrane functionality dropped while sperm DNA damage increased. HS and HM groups had significantly lower histomorphometric parameters, TAC, GPx, SOD, GSH, and Bcl-2 gene expression. MDA, NADP+/NADPH, Bax, Caspase-1, and GSDMD gene expression were substantially higher in the HS and HM groups than in the control group.

CONCLUSIONS

Toxic effects of hypertonic saline and mannitol on reproductive parameters were seen following, hence, they might be considered as a good chemical sterilizing treatment in donkeys.

GnRH-immunocastration: an alternative method for male animal surgical castration

Castration of male animals is intended to produce high-enhance quality of animal meat, prevent unpleasant taste, reduce aggressive behavior, and manage overbreeding. Over the years, Tranditional methods of mechanical and surgical castration have been employed over the years, but they fall short of meeting animal welfare requirements due to the associated risk of infection, pain, and stress. Immunocastration, specifically Gonadotropin-releasing hormone (GnRH)-immunocastration, targeting the hypothalamic-pituitary-testis (HPT) axis, has emerged as an animal-friendly alternative to surgical castration, effectively addressing these issues. This review seeks to systematically summarize the principles, development, current applications and challenges of GnRH-immunocastration, offering insights into its role in promoting animal welfare.

The Pathological and Ultrasonographic Evaluation of the Chemical Castration in Dogs using Calcium Chloride Injection

Many researchers have been curious about the chemical sterilization method, which may be a choice of castration. The 20% calcium chloride ethanolic solution can prevent animals from some tumors and control the side effects of surgical castration. This experiment divided 12 male mixed-breed dogs into sham and chemical groups (n=6). Normal saline and 20% calcium chloride (20 ml/testis) were injected in the sham and chemical group's testis, respectively. Ultrasonography and related scoring were operated at 0-, 7-, 14-, and 2-days post-injection to evaluate echogenicity and measure the left testes' dimensions. Blood samples were taken on days 0, 7, 14, and 21 of the experiment evaluating the superoxide dismutase (SOD), glutathione peroxidase (GPx), and testosterone levels. The semen in the left epididymis of the chemical group was aspirated on day 21 post-injection for counting the sperm numbers. The testes of all dogs were surgically removed at 21 days post-injection, and the left one was put in formaldehyde for tissue processing. The intertubular edema, necrosis of the seminiferous tubules, neutrophil infiltration, and calcification was scored. The average dimensions of the chemical groups' left testes significantly decreased 7, 14, and 21 days after injection. The echogenicity of the testes decreased in the chemical group. A significant echogenicity difference was observed between the first day and the 7th and 14th day in ultrasonography. Calcium chloride injection failed to reduce the mean testosterone levels on all experimental days compared to day zero. Otherwise, the sperm number in the left testes of the chemical group decreased on day 21 post-injection. The degree of intertubular edema with neutrophil infiltration and severe tubular necrosis in the chemical group was significantly higher than in the sham group on the experimental days, including 7, 14, and 21. The mild calcification in the chemical group is likely the reason for higher echogenicity on day 21. The scrotum was swelled and ulcerated in the chemical group. Ultrasound is effective in demonstrating the castration ability of calcium chloride in the chemical method. Due to the inflammatory clinical effects, the chemical method is recommended in dogs only when surgical methods are unavailable.

Hypertonic Activity of Injection Solutions Can Cause Post-injection Complications (Review)

Introduction. A review of the scientific literature showed that the current standards for assessing the quality of drugs does not include an assessment of the osmotic activity of drug solutions and their local irritant effect on tissues at the sites of subcutaneous, intramuscular and intravenous injections. Therefore, currently injectable solutions considered to be of high quality may not have isotonic activity and high postinjection safety.

Text. A study of the concentration range of quality drug solutions ready for injection showed that the acceptable concentration value of the main ingredients is in the range of 0.01 to 76 %. Direct measurement with an osmometer of the osmotic activity of injection solutions, considered qualitative today, has shown that injection solutions can have hypotonic, isotonic and hypertonic activity and their osmotic activity can be in the range of 0 – 3900 mosmol/l water. Study of acidic activity of drug solutions showed that in accordance with pharmacopoeial requirements of drug quality modern quality drug solutions ready for injection can have acidic, neutral or alkaline activity. Solutions with hypertonic activity have been found to have a local irritant effect. Moreover, an increase in hypertonic activity of drug solutions increases their local irritant effect. It has been found that excessively high hypertonic activity of drug solutions may be the cause of the development of a local postinjection complication known as "Nicolaou syndrome", the cause of which has remained unknown for a long time. Nicolaou syndrome includes local pain syndrome, aseptic inflammation, necrosis, and abscess.

Conclusion. The authors conducted a literature review, the results of which led to conclusions and assumptions. Solutions containing drugs in concentrations greater than 10 % may have the highest hypertonic activity, which can cause excessive dehydrating, local irritating and cauterizing effects. Therefore, injections of such drugs are most dangerous with the development of post-injection necroses and abscesses. That is why timely dilution of concentrated drug solutions with water by 2–10 times increases injection safety. It is proposed to include the assessment of osmotic activity and local irritant effect of drug solutions in the standard of drug quality control.

Gold nanoparticle intratesticular injections as a potential animal sterilization tool: Long-term reproductive and toxicological implications

This study aimed to evaluate the gold nanoparticles (AuNPs) animal sterilizing potential after intratesticular injections and long-term adverse reproductive and systemic effects. Adult male Wistar rats were divided into control and gold nanoparticle (AuNPs) groups. The rats received 200µL of saline or AuNPs solution (16µg/mL) on experimental days 1 and 7 (ED1 and ED7). After 150 days, the testicular blood flow was measured, and the rats were mated with females. After mating, male animals were euthanized for histological, cellular, and molecular evaluations. The female fertility indices and fetal development were also recorded. The results indicated increased blood flow in the testes of treated animals. Testes from treated rats had histological abnormalities, shorter seminiferous epithelia, and oxidative stress. Although the sperm concentration was lower in the AuNP-treated rats, there were no alterations in sperm morphology. Animals exposed to AuNPs had decreased male fertility indices, and their offspring had lighter and less efficient placentas. Additionally, the anogenital distance was longer in female fetuses. There were no changes in the histology of the kidney and liver, the lipid profile, and the serum levels of LH, testosterone, AST, ALT, ALP, albumin, and creatinine. The primary systemic effect was an increase in MDA levels in the liver and kidney, with only the liver experiencing an increase in CAT activity. In conclusion, AuNPs have a long-term impact on reproduction with very slight alterations in animal health. The development of reproductive biotechnologies that eliminate germ cells or treat local cancers can benefit from using AuNPs.

Surgical castration versus chemical castration in donkeys: response of stress, lipid profile and redox potential biomarkers

Background

Castration is a husbandry practice raising important questions on the welfare and physiological status of farm animals. Searching for effective castration methods that minimally compromise the body physiology is worthy of attention. Therefore, this study aimed to evaluate the differential response of biological systems in donkeys to surgical castration versus the chemical one by CaCl₂ with special emphasis on stress, lipid profile, and oxidative stress biomarkers. Donkeys were divided randomly and equally into two groups; the chemical (Ch) and surgical (S) groups (n = 6). The Ch group was chemically castrated by intratesticular injection of 20% CaCl₂ dissolved in absolute ethanol. Blood samples were collected prior to castration and at 15, 30, 45, and 60 days after the beginning of experiment.

Results

Surprisingly, the Ch group at the end of the experiment was characterized by significantly higher cortisol level compared to the S group. TC and LDL-C levels in the S group significantly decreased at day 45, while TG levels significantly increased at days 45 and 60 in comparison with day 0. HDL-C levels at days 30 and 60 in the Ch group significantly increased in comparison with day 0. At day 30 post-castration, HDL-C was significantly higher and LDL-C was significantly lower in the Ch group than the S group. A significant elevation in TC and LDL-C was observed at day 45 and in HDL-C at the end of experimental duration in the Ch group when compared with the S group. TPX level was significantly lower and TAC was significantly higher in the Ch group at day 45 than the S group.

Conclusion

Surgical castration evoked less stress and minor changes in lipid profile and oxidant/antioxidant balance relative to chemical castration by intratesticular 20% CaCl₂ dissolved in absolute ethanol.

Fertility Control in Wildlife: Review of Current Status, Including Novel and Future Technologies

Wildlife conservation requires varying degrees of management of endangered species as well as management of their potential predators and competitors. Conservation also depends on ameliorating human-wildlife conflict, especially where there is a threat to the safety of people and of their pets and livestock. In addition, sustainability of wildlife populations can be affected by feral domestic animals or invasive species, that require removal or control. With the increasing concern for animal welfare, non-lethal methods of limiting population size and distribution, such as fertility control, are gaining favor. Breeding programs in zoos depend on highly effective and selective contraception to manage sustainable insurance populations. This review covers fertility control methods currently in use, those that have not lived up to past promises, and others that are under development and present hope for addressing remaining challenges.

Evaluation of Newly Developed Chemical Castration Method: Changes in Hormone Gene Expression of Hypothalamic-Pituitary Axis

Surgical castration (also known as orchidectomy, ORX) has been frequently performed to avoid uncontrolled breeding. However, it has some serious disadvantages. Several laboratories have developed chemical castration methods, using bilateral intratesticular injection (BITI) of simple chemical solutions. The present study was undertaken to compare the effects of ORX and of hypertonic saline BITI on the androgen-sensitive tissues such as pituitary and hypothalamus. Serum testosterone (T) levels of ORX animals and hypertonic saline BITI animals (SAL) after 4 weeks of the manipulations exhibited significantly drops as compared with the levels of intact animals (Intact:ORX:SAL = 7.74± 1.31:1.34±0.19:1.28±0.18 ng/ml, p<0.001). Both ORX and BITI method induced similar stimulatory effects on the pituitary gonadotropin subunits and hypothalamic KiSS-1 gene expressions. In contrast, the effects of ORX and hypertonic saline BITI on hypothalamic GnRH gene expression were different from these gene expressions, shown an inverse relationship between the two groups (Intact:ORX:SAL = 1:0.45±0.06:1:2.07±0.41:1.51±0.37 AU; ORX, p<0.001; SAL, p<0.05). In conclusion, we provided evidence that hypertonic saline BITI method has equivalent efficacy of T depletion to surgical castration in rats. The present study suggests the hypertonic saline BITI could be a promising substitute to conventional surgical castration.