A Stereological Study of Mouse Ovary Tissues for 3D Bioprinting Application

Introduction The use of 3D-bioprinted ovaries has been proven to be a promising technique for preserving fertility. Stereology is an accurate method to obtain quantitative 3D information and the stereological data is the basis for 3D bioprinting ovaries. Methods In this study, six female mice were used to acquire the ovarian tissues. One of the two paraffin-embedded ovaries of each mouse was cut into 5 µ m sections, and the other was cut into 15 µ m sections and then subjected to haematoxylin and eosin staining and anti-follicle stimulating hormone receptor antibody immunohistochemistry. The volume and volume fractions of ovaries were measured by the Cavalieri method. Then, the numerical densities and total numbers of ovarian granulosa cells (OGCs) and primordial, preantral and antral follicles in serial sections were estimated using design-based stereology. Results The ovarian volume was 2.50 ± 0.32 mm 3 . The volume fractions of the cortex, medulla, follicles and OGCs were 86.80% ± 2.82, 13.20% ± 2.82%, 5.60% ± 0.25% and 81.19% ± 2.57%, respectively. The numerical densities of OGCs, the primordial, preantral and antral follicles were 2.11 (± 0.28) × 10 6 /mm 3 , 719.57 ± 18.04/mm 3 , 71.84 ± 3.93/mm 3 and 17.29 ± 3.54/mm 3 , respectively. The total number of OGCs and follicles per paraffin-embedded ovary were 5.26 (± 0.09) × 10 6 and 2013.66 ± 8.16. Conclusions The study had obtained the stereological data of the mice ovaries, which contribute to a deeper understanding of the structure of the ovaries. Meanwhile, the data will supply information for 3D bioprinting ovaries.