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Hyperthermia, Nanotechnology, Ultrastructure, oxidative stress
Currently, castration of male animals is the most effective method of population control of stray animals. However, despite the effectiveness of surgical castration, its use is unfeasible for large-scale applications. Therefore, new alternatives have emerged to castrate animals without the need for a surgical procedure. With the evolution of nanotechnology, nanoparticle-mediated hyperthermia methodologies have been a promising strategy. However, despite the good results from hyperthermia mediated by nanoparticles, their action on cells and the mechanisms of cell damage and death have not yet been elucidated. Therefore, our work aimed to evaluate cellular and structural changes caused by the nanoparticle-mediated photohyperthermia (FHT) procedure in the testes of Wistar rats. For this, we used 32 male animals divided into two groups: control (n=9) and FHT (n=24). Subsequently, the FHT group was subdivided according to the day of euthanasia after the procedure: 24 hours group (FHT 24h), 72 hours group (FHT 72h), and 7 days (FHT 7d). After executing the protocol, the animals were euthanized and their organs (testicles, epididymis, kidney, liver, spleen, and lung) were used for the analysis of histology, ultrastructure, ROS quantification, respirometry, and nanoparticle quantification by FMR. Preliminary results show histological damage in the FHT 24h group with the onset of vacuolization, which progressed to advanced degeneration of the germinal epithelium and tubular retraction after 7 days (FHT 7d). In mitochondrial respiration, the 72h FHT group showed a reduction in parameters compared to the control and the other treatments. Therefore, the results obtained so far show us an increasing degeneration of cell damage over the days after the FHT procedure, which already shows relevant signs after 24 hours (FHT 24h). Therefore, this study is expected to elucidate some mechanisms involved in the tissue degeneration process triggered by nanoparticle-mediated photohyperthermia when applied to the testicles to induce sterility in male animals.