Nanoparticle-mediated hyperthermia for male cat neutering: Disrupting fertility without surgery

This study aimed to evaluate magnetic nanoparticle-mediated hyperthermia (MNH) as a potential method to induce infertility in male cats. The short- and long-term effects of the treatment on reproductive health parameters were assessed in 20 cats. Treatment consisted of a 150 μL intratesticular injection of a magnetic fluid composed of citrate-coated manganese ferrite (Ci-MnFe₂O₄) nanoparticles, followed by the application of an external magnetic field to raise and maintain testicular temperature at 45 °C for 15 min. Testicular MNH was found to be safe and well tolerated, with no signs of pain or clinical side-effects. Testicular volume increased significantly on Day 7 due to peritesticular inflammation, followed by a marked decrease on Day 180. Azoospermia was observed in 85 % of the treated animals, while 15 % were oligospermic. Histological analysis revealed substantial damage to seminiferous tubule architecture and epididymides. No hematological, biochemical or abdominal ultrasound abnormalities were observed in the treated animals. These findings demonstrated the strong potential of testicular magnetic hyperthermia mediated by Ci-MnFe₂O₄ nanoparticles as a non-surgical alternative method for male cat sterilization.