Intratesticular injection of hypertonic saline : non-invasive alternative method for animal castration model

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.

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.

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.

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.

Androgenic effects of aqueous and methanolic extracts of Ficus asperifolia in male Wistar rats

BACKGROUND

Androgen deficiency is a clinical syndrome resulting from the inability of the testes to produce physiological levels of testosterone due to a disturbance occurring at one or more levels of the hypothalamic-pituitary-testicular axis. The present study was undertaken to evaluate the androgenic properties of aqueous and methanolic extracts of Ficus asperifolia on normal and castrated immature rats.

METHODS

Normal rats were treated either per os with aqueous or methanolic extract of Ficus asperifolia (100 mg/kg or 500 mg/kg b.w.), distilled water (10 ml/kg b.w.), 5% Tween 80 (10 ml/kg b.w.) or subcutaneously with testosterone propionate (0.5 mg/kg b.w.). Castrated rats were treated with plant extracts (100 mg/kg b.w. or 500 mg/kg b.w.) alone or with the co-administration of plant extracts and testosterone propionate (s.c., 0.5 mg/kg b.w.) or bicalutamide (2 mg/kg b.w. per os). Animals were treated once a day during four weeks. Body weight growth and relative sexual organ weights were recorded at the end of each treatment. Some biomedical parameters were measured in the plasma (proteins, cholesterol), testes (cholesterol) and epididymis (proteins).

RESULTS

In normal rats, Ficus asperifolia significantly (p < 0.05) increased the relative weights of the testes and all sexual-dependent organs whereas total testicular cholesterol concentration was significantly (p < 0.05) decreased. In castrated groups, treatment with Ficus asperifolia was followed by an increase in the sexual organ weights, epididymal protein and prostatic acid phosphatase concentrations. The co-administration of testosterone and plant extracts significantly (p < 0.05) increased the weight of accessory sexual organs and epididymal protein contents. In the presence of bicalutamide (an anti-androgen), the sexual stimulating activity of Ficus asperifolia was diminished with remarkable effects on vas deferens weight (p < 0.05), plasma (p < 0.01) and epididymal (p < 0.05) protein contents.

CONCLUSION

Ficus asperifolia possesses androgen-like activity through possible stimulation of cytoplasmic and/or nuclear receptors by the bioactive compounds found in its extracts.