Visualization of Changes in the Kidneys, Testes, Ovaries, and Uterus of Rats During Plastination, and Their Evaluation by SEM and Histology

(1) Background: To address formaldehyde-related health hazards and cadaver scarcity in anatomy education, silicone plastination offers a biosafe alternative, yet organ-specific structural responses at each stage remain inadequately characterized. (2) Methods: This study evaluated sequential microanatomical and ultrastructural changes in rat urogenital organs (kidney, testis, ovary, and uterus; n = 20 Sprague–Dawley rats) across four plastination stages (fixation, dehydration, forced impregnation, and gas curing) using light microscopy (H&E, Alcian Blue-PAS) and scanning electron microscopy (SEM). (3) Results: Histological and SEM analyses revealed that tissue architecture was well preserved during initial fixation and dehydration. Conversely, forced impregnation and gas curing induced the most pronounced structural alterations, including tubular shrinkage and false PAS positivity in the testis, parenchymal fragmentation in the ovary, and loss of uterine luminal microvilli. Ultrastructurally, polymer deposition masked glomerular and tubular surface topography in the kidney and testis. Overall, kidney and uterine tissues maintained basic histological recognizability better than gonadal tissues. (4) Conclusions: These findings demonstrate that structural damage peaks during forced impregnation and curing, establishing organ-specific vulnerability and underscoring the necessity of tissue-tailored plastination protocols.