A stereological study of 3D printed tissues engineered from rat vaginas

Background This study aims to retrieve the stereological data from rat vaginas for 3D printing tissue-engineered vaginas. Methods In this study, five female Sprague-Dawley rats, aged 8-12 weeks, were used to obtaining the vagina tissues. Each vagina was divided into eight segments fixed in 4% paraformaldehyde and embedded in paraffin, whose two consecutive sections of each block were stained using hematoxylin and eosin (H&E) and anti-α-actin antibody with immunohistochemistry staining, respectively. The thickness of the epithelium, lamina propria, the smooth muscle layer, and the adventitia layer are measured. Then, the volume density of the epithelial cells and smooth muscle cells are counted using design-based stereology. Results The length and width of the rat vaginas were 2 and 1.5 cm, respectively. The thickness of the epithelium, lamina, propria, and adventitia layer was measured, and no significant difference was observed. However, the thickness of the smooth muscle layer was significantly different among these eight segments. The smooth muscle layer of the lower vagina is thicker than the upper vagina. The average volume density of epithelial cells and smooth muscle cells is 1.61×109/cm3 and 5.38×108/cm3. There was a significant difference observed. Conclusions We had successfully retrieved the stereological data of the vaginas. The gained data will supply us with the information for 3D printing vaginas and new insights into the structure of the vagina.