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.
Keywords: Chemical castration; Dog; Pathology; Ultrasonography.