Application of three dimensional histological reconstruction technology research testicular descent on mice / 中华实用儿科临床杂志

ABSTRACT

Objective:To explore the testicular descent process and temporal morphology and position changes of its neighboring tissues and organs in mice with three dimensional (3D) histological reconstruction technique.Methods:Tissue below the kidney plane of male Kunming mice was harvested on gestation days (GD)15, GD17, GD19, postnatal days (PD)3 and PD7.The tissue was then serially sectioned and stained with hematoxylin and eosin (HE). Slices were scanned and saved by the PerkinElmer automatic section analysis system.Afterward, Photoshop software was used for image registration and alignment, and 3D-doctor software was employed for 3D reconstruction and analysis.Results:(1)The epididymis enveloped the testis, and the tail of the epididymis was connected with the gubernaculum, but no direct connection was found between the lower pole of the testis and the gubernaculum.During pregnancy, each part of the epididymis and the vas deferens of mice were piled up into a mass, making it hard to identify the epididymis.The gubernaculum leads to " swelled" . After birth, the epididymis became large, elongated, and morphologi-cally recognizable, and the gubernaculum degenerated into fibrous cords.During the whole process, the volume of gubernaculum was significantly smaller than that of testicle.(2)Testicles on both sides were similar in shape and asymmetrical in position.The left testicle was lower than the right testicle, and descended before the right one.During pregnancy, testicles on both sides descended from the lower pole of the kidney, the left testical stopped at the lower part of the bladder.and the right one stopped at middle part of the bladder.After birth, the left testicle dropped below the neck of the bladder.Finally, the left testicle was lower than the right testicle.(3) The epididymis descend prior to the testicles.Throughout the process, the tail of the epididymis descended before the testicles, and it pulled the whole epididymis down.Testicles entered the scrotum along the descending path of the epididymis.After the complete descent, the tail of the epididymis remained below the testicles.Conclusions:Through observation, the testicular descend process in mice includes the following steps.First, the tail of the epididymis is pulled down to the inner ring by the gubernaculum, and the tail and body of the epididymis expand the inner ring and the inguinal canal through their morphological changes.The epididymis then continues to go down into the scrotum and expands it.Finally, the testicles and the head of the epididymis follow the epididymis body and enter the scrotum through the enlarged inner ring and inguinal canal.