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 ۲۰% calcium chloride ethanolic solution can prevent animals from some tumors and control the side effects of surgical castration. This experiment divided ۱۲ male mixed-breed dogs into sham and chemical groups (n=۶). Normal saline and ۲۰% calcium chloride (۲۰ ml/testis) were injected in the sham and chemical group's testis, respectively. Ultrasonography and related scoring were operated at ۰-, ۷-, ۱۴-, and ۲-days post-injection to evaluate echogenicity and measure the left testes' dimensions. Blood samples were taken on days ۰, ۷, ۱۴, and ۲۱ 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 ۲۱ post-injection for counting the sperm numbers. The testes of all dogs were surgically removed at ۲۱ 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 ۷, ۱۴, and ۲۱ 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 ۷th and ۱۴th 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 ۲۱ 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 ۷, ۱۴, and ۲۱. The mild calcification in the chemical group is likely the reason for higher echogenicity on day ۲۱. 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.