Sterilization in animals serves multiple purposes, such as behavior control, performance improvement, and population management. Chemical sterilization has emerged as a promising non-surgical alternative to traditional methods. This study aimed to investigate the effects of intra-testicular injection of zinc-doped carbon dots (Zn-CDs) nanoparticles as a chemical sterilant in mature rats. Twenty-five rats were randomly divided into five groups, including a control group without injection, a sham group receiving 0.50 mL distilled water, and three treatment groups administered respectively 0.50, 2.00, and 8.00 mg kg-1 of Zn-CDs synthesized through a hydrothermal process. Following anesthesia with ketamine and xylazine, and aseptic preparation, intra-testicular injections were administered bilaterally. At 60th day post-injections, blood samples were collected to measure serum testosterone levels using chemiluminescence immunoassay. The rats were then surgically castrated to assess sperm parameters and testicular histopathology. Testicular oxidant/anti-oxidant status was also evaluated. The results revealed a dose-dependent reduction in sperm viability, membrane integrity, and motility, accompanied by increased sperm DNA damage. The highest Zn-CDs dose caused the most significant decrease in sperm concentration, as well as severe testicular tissue damage. In addition, anti-oxidant capacity, seminiferous tubules maturation, testosterone production, and spermatogenesis declined with increasing Zn-CDs concentrations in a dose-dependent manner. These findings indicate that intra-testicular injection of Zn-CDs effectively induces infertility in mature rats and holds potential as a chemical sterilization method. With further studies to evaluate safety and efficacy, this approach could be developed as a practical solution for large-scale in situ castration, offering a non-surgical alternative for over-population control programs.
Farjah et al. (Wed,) studied this question.