Testicular descent revisited: a micro-computed tomography study in fetal rats.

Purpose: There is a long history of research dealing with the embryology of the testicular descent. However, important aspects like the role of the gubernaculum and the development of the processus vaginalis peritonei are not understood. Micro-computed tomography (µCT) is an established tool for anatomical studies in rodents. Our study applied µCT imaging to visualize the testicular descent in rats and focused on the role of the gubernacular bulb and the development of the processus vaginalis peritonei.

Methods: Rats from embryonic day 15 (ED15) to ED21 and newborns (N0) were fixed and dried using the "critical point" technique. We ran a SkyScan µCT system and scans were analyzed for gender-specific differentiation of the genital ridge and used for 3D visualization of relevant anatomic structures.

Results: µCT imaging confirmed the intraperitoneal location of the testicles from ED15 to N0. The components of the inner genital moved closer together while the intestinal volume expanded. The gubernacular bulb seemed to be involved in the formation of the processus vaginalis peritonei.

Conclusion: Here, we utilized µCT imaging to visualize the testicular descent in the rat. Imaging provides new morphologic aspects on the development of the processus vaginalis peritonei.