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|Title:||The effect of male accessory sex glands on embryo development and implantation in the golden hamster|
|Subjects:||Golden hamster -- Reproduction.|
Golden hamster -- Physiological aspects.
Generative organs, Male.
Hong Kong Polytechnic University -- Dissertations
|Publisher:||The Hong Kong Polytechnic University|
|Abstract:||The accessory sex glands (ASG) are present in most male mammals. They include of the seminal vesicles, coagulating glands, ampullary gland (AG), the dorsolateral and ventral prostate (VP). Secretions from these glands contribute to the bulk of seminal plasma which plays a role in gamete transfer. However, recent research on the golden hamster has established that these glands are essential for the maintenance of reproductive efficiency by ensuring successful progression of embryonic development. Removal of some (VP, AG) or all of the ASG can lead to reduction in number of normal embryos, implantation failure and eventually reduction the number of live births. In this project the golden hamster was used as an animal model. The investigation focused on embryonic development from the 5th to the 7th day after mating. There were four groups of males involved i.e. total removal of ASG (TX), bilateral removal of VP (VPX) or AG (AGX) and sham-operated (SH) animals which formed the control group. Firstly, morphological criteria were applied to all experimental groups to find out if development deviated from the normal pattern. Results showed that the TX and VPX embryos had reduced embryonic cell number and embryo volume. A higher percentage of abnormal and degenerated embryos were also noted in these groups. In the second experiment, the effect of the male accessory sex glands on the cell proliferation and programmed cell death was studied. Proliferating cell nuclear antigen (PCNA) immunostaining and terminal deoxynucleotide transferase-mediated dUTP nick end labeling (TUNEL) methods were used. The data showed that there was no difference in the occurrence of apoptosis in the embryonic cells among the four treatment groups. However, compared with the SH controls, thane was a significantly lower level of positive PCNA embryonic cells in the VPX and TX groups.|
In another experiment, the effect of male ASG on the expressions of vascular endothelial growth factor (VEGF) and its receptors were studied. RT-PCR, In situ hybridization, immunohistochemistry, Western blotting and ELISA techniques were used. Semiquantitative RT-PCR and ELISA revealed significantly lower expression of VEGF mRNA and protein in the TX and VPX groups embryos and endometrium. Removal of all or part of the male ASG association with abnormalities in embryo development, and reduced production of VEGF implied inadequacy in angiogenesis and oxygen utilization by the embryo. Both of these factors may cause implantation failure. Significantly deficient of FLt-1 and Flk-l expression in the endometnum was also determined by ELIS A and immunohistochemical methods. Finally, the effect of the male ASG on the expression of gas6 and its receptors were studied. The expression of gas6 mRNA and GAS6 by the pregnant uterus enabled us to conclude for the first time that gas6 and its receptors are involved in mammalian embryo implantation. Significantly different expressions of GAS6 mRNA and proteins by decidual tissue and embryos in the TX and VPX group were found respectively. Expression of three types of GAS6 receptors: Axl, Rse and Mer were studied in this experiment. Significantly difference expression of Rse and Mer were also determined on embryo and endometrium from VPX and TX groups respectively. In conclusion, our data demonstrate that the absence of male ASG at the time of mating adversely affects cell proliferation and differentiation of the embryos as well as decidualization and angiogenesis of the endometnum. As the expression of VEGF and GAS6 in the endometrium depends on the presence of the embryo, the ASG probably exert their effects primarily on the embryo. The ventral prostate gland is important in ensuring healthy growth of the embryo, whereas the ampullary gland did not appear to be essential during the critical implantation period of embryo development.
|Description:||xvi, 308 leaves,  leaves of plates : ill. (some col.) ; 30 cm.|
PolyU Library Call No.: [THS] LG51 .H577P ABCT 2000 Jiang
|Rights:||All rights reserved.|
|Appears in Collections:||ABCT Theses|
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