A Morphological Study With Serial Histological Slices On The Testis And Gubernaculum In Normal And Exposed-Diethylstilbestrol Newborn Male Mice

Objective: In the recent years, it is know that the prevalence rate of congenital genitalabnormalities has been increased rapidly, the mechanisms studies were advanced accordingly.Whether there were abnormalities and how about the degrees were the most important factors forthe mechanisms' studies, and also, the bases for the study of etiology, diagnosis and treatment.However, there was not enough study on the standard of congenital genital abnormalities'determinant. Especially for the complicated genital system and its systematical and multiplemalformations. The present standards of malformation confirmation were out of date and notprecise. It is very difficult to fit the present studies such as the researches on the effects ofenvironmental low-dose chemicals. The more accurate techniques and methods were needed todetermine and evaluate the formation of abnormalities. In this study, the whole genital systems ofnewborn male mice which include an animal model of diethylstilbestrol (DES) treated mice werefixed in situ, set for transected serial slices and studied under microscopy. The morphology oftestis and gubernaculum were primarily studied by this method in this study in order to check thefeasibility of serial slices microscopic histological study on the elaborate evaluation ofreproductive system malformations.Materials and methods: 120 8-10 weeks old Kunming female mice were randomly divided intoeight groups, that is, normal group (not given any drug), control group (given DMSO and NS),and experimental groups 1-6: DES were be given 0.1, 0.5, 10.0, 25.0, 50.0 and 100.0μg.kg^-1d^-1respectively (DES dissolved in DMSO and NS). The newborn mice, when they were delivered,were collected at once for the determination of sexuality. And then, three of them were randomlyselected from each group. All the selected newborn mice were treated as follows: the parts ofabdomen were fixed in situ and set to transected serial slice. All the slices (HE prepared and 5μm thick) ware recorded serially and studied under microscopy. Data were being statisticallyanalyzed thereafter.Results: 1. The testes of newborn mice in normal and control groups were all well developed,they located in two sides of the bladder' neck, and far away from the kidney. In the experimentalgroups, the testes volumes of newborn mice were smaller than those of normal and controlgroups. They later near the kidney and correspondence to DES' dosage. The gubernaculums of all groups were all slender and diaphanous, and they were all difficult to accurately quantify. 2.In the serial transects of normal newborn mice, the tissue images demonstrate that the testes wereall in round shape and the curves were smooth. The positions of right testes were all higher thanthose in left. The diameter of left testis was about 682±8um, and it is about 668±8μm in the right.The distance between kidney and testis in the left is about 1648±8um, and it is about 1350±9μmin the right. The testis and epididymides narrowed downwards and gradually varied andcoalesced into gubernaculum. The gubernaculums were fully developed with well-demarcatedmesenchymal inner core and muscular outerlayer. The low end immerged into scrotum and partof gubernacular tissue had close relationship to pubic periosteum. The length of gubernaculum inleft was about 353±15um, but it's about 598±8μm in right. The configuration of gubernaculumcan be identified clearly: The structure of gubernaculum is not homogeneous from proximal todistal. And the right and left were also obvious dissymmetric. 3. In the experimental group, theserial transects of normal newborn mice showed the testis did not develops well and the shapeswere not regular round. The space between kidneys and testis, the diameter of testes were allshorter obviously than that of normal and control groups (P＜0.05). They all have curvilinearcorrelations with DES dosage (y=a+bx+cx²). Among them, the diameter of left testis:a=661.3988, b=21.875, c=-5.98214, s=18.1615, r=0.9772; The diameter of right testis:a=645.4762, b=20.63492, c=-5.83333, s=12.1646, r=0.9894. The left space between kidney andtestis: a=1789.167, b=-82.8373, c=-6.88492, s=48.4216, r=0.9909; The right space betweenkidneys and testis: a=1515.714, b=-98.0556, c=-5.15873, s=59.0398, r=0.9864. Thegubemaculum seemed to be undifferentiated and the demarcation between the mesenchymal coreand the muscular outer layer was unclear. The effects of environmental estrogens on every partof gubemaculum is different and obviously. The length of gubemaculum has curvilinearcorrelation with DES dosage (y=a+bx+cx²), in the left: a=640.5124, b=5.3127, c=-0.03274,s=28.6130, r=0.9667; theright: a=395.8851, b=5.3332, c=-0.03272, s=25.5255, r=0.9737.Conclusions: 1. Method of studying the testis and gubernaculum with serial tissue sections isfeasible for the genital organs' morphological study in newborn mice. It is either good to studythe genital organs' form and structure in micro-level or beneficial to measure the size andpositions of genital organs indirectly. By this method, the whole genital organs' morphology andhistology can be investigated at the same time. The research results are of course systematical. 2. The method of studying the whole genital system with serial tissue sections is valuable for thegenital organs' morphological study in newborn DES mode mice. The results are better thanthose traditional methods. 3. For the newborn mode mice exposed on environmental estrogens:the degrees of the DES effects on testis and gubernaculum have curvilinear correlation with DESdosage. The effects of environmental estrogens on every part of gubernaculum are different andobvious. 4. The method of studying the testis and gubernaculum with serial tissue sections isbeneficial to carry out organ' three-dimensional reconstruction.