Sperm mobility denotes the net movement of a sperm population. Previous work implicated mitochondrial function as a basis underlying phenotypic variation in this quantitative trait. Our objective was to determine if mitochondrial function was indeed critical to expression of phenotype. Phenotype was assigned to roosters within a random bred population (n=242). A representative subpopulation (n=40) was used to correlate sperm mobility with oxygen consumption (r=0.83). In contrast, sperm mobility was independent of mitochondrial helix length in a sample of males (n=7) representing the range of phenotype observed within the population. Thus, mitochondrial function rather than number appeared to be critical to expression of phenotype. This hypothesis was tested by ultrastructural analysis of sperm midpieces. Males from the lower and upper tails of the distribution were characterized with high and low proportions of sperm containing aberrant mitochondria in 47 and 4% of the cells respectively. When sperm from average males were allowed to segregate into immobile and mobile subpopulations, 40% of immobile sperm contained aberrant mitochondria. In contrast, only 9% of sperm from the same males contained aberrant mitochondria in non-segregated populations. In conclusion, the mitochoridrion is an organelle that may account for phenotypic differences in sperm mobility. / Graduation date: 2002

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

Spermatozoa experience a series of physiological alternation upon traveling from the testis to the epididymis in order to acquire motility and capacity necessary to recognize and to fuse with an oocyte. Further maturation and modification of the spermatozoa occur along the journey in the female reproductive tract in a process known as capacitation. p53 protein is a well-known transcription factor involved in guarding of genome integrity by triggering cell cycle arrest and cell death upon DNA damage. p53-binding protein 1 (53BP-1) binds to p53 and enhances p53-mediated transcriptional activity. It has been reported that human spermatozoa produce 53BP-1 for DNA repair in response to oxidative stress. 53BP-1 is expressed in pre-implantation embryos. The current study aimed to identify the expression and subcellular location of 53BP-1 proteins in mouse spermatozoa by immunofluorescence staining. Increased expression of 53BP-1 proteins was found in the swim-up and capacitated mouse spermatozoa. The immunoreactivity was localized to the sperm head and midpiece, suggesting possible roles of 53BP-1 in sperm function. It was also found that mouse oocytes and 1-cell embryo also expressed 53BP-1. The potential function of 53BP-1 in early embryo development was also investigated using 53BP-1 antibody neutralized sperm in in-vitro fertilization. There was no significant difference between the development rate of embryos fertilized with spermatozoa transduced with anti-53BP-1 antibody and those that transduced with the control goat IgG. Further studies are needed to investigate the role of sperm 53BP-1 at later stage of embryo development and implantation. / published_or_final_version / Obstetrics and Gynaecology / Master / Master of Medical Sciences

Oxidative damage by reactive oxygen species (ROS) is a major cause of sperm dysfunction. Excessive ROS generation reduces fertilization and enhances DNA damage of spermatozoa. In mammals, including humans, oviduct functions as a sperm reservoir which is created by the binding of spermatozoa to the epithelial lining in the oviduct. Interaction between sperm and oviductal epithelial cells improves the fertilizing ability of and reduces chromatin damage in spermatozoa. However, the mechanism(s) by which spermatozoa-oviduct interaction producing these beneficial effects is unknown. One possibility is that oviduct protects spermatozoa from oxidative stress. The hypothesis of this project was that oviductal cell membrane proteins interact with spermatozoa to protect them from oxidative damage. Due to the limited availability of human oviductal tissue for research, an immortalized human oviductal epithelial cell line, OE-E6/E7, was used as a study model. The first objective examined the effect of OE-E6/E7 membrane proteins on human spermatozoa. The extracted OE-E6/E7 membrane proteins bound to sperm head and preferentially to uncapacitated sperm. Pretreatment with OE-E6/E7 membrane proteins significantly suppressed ROS-induced adverse effects in sperm motility, membrane integrity, DNA integrity, and intracellular ROS level. OE-E6/E7 membrane proteins also increased the endogenous enzyme activities of sperm superoxide dismutase (SOD) and glutathione peroxidase (GPx). Sperm fucosyltransferase-5 (sFUT5) is a membrane carbohydrate-binding protein on human sperm. The second objective investigated the involvement of sFUT5 in sperm-oviduct interaction. Purified sFUT5 bound to OE-E6/E7 cells and anti-FUT5 antibody inhibited this interaction. Pre-absorption of OE-E6/E7 membrane proteins with purified sFUT5 or blocking of sFUT5 on sperm with anti-FUT5 antibody significantly inhibited the protective effects of OE-E6/E7 membrane proteins against ROS-induced damages in spermatozoa. Asialofetuin, a reported sFUT5 substrate, can partly mimic the protective effect of OE-E6/E7 membrane proteins. Sperm processing in assisted reproductive technology (ART) treatment, including centrifugation and cryopreservation, has shown to induce ROS production and oxidative damage in sperm. The third objective investigated the possible use of OE-E6/E7 membrane proteins or asialofetuin as an antioxidant supplement during centrifugation and cryopreservation. No adverse effect on sperm functions was detected by centrifugation using our centrifugation protocols. OE-E6/E7 membrane proteins or asialofetuin pretreatment suppressed the cryopreservation-induced damage on sperm in terms of motility and DNA fragmentation. The fourth objective aimed to identify the sFUT5-interacting proteins from OE-E6/E7 membrane extracts. By using immuno-affinity chromatography and mass spectrometry analysis, cell adhesion molecule 4 (CADM4) was identified as a potential sFUT5-interacting protein. This result was further supported by co-immunoprecipitation, immunofluorescent staining and immunohistochemistry. CADM4 expression level was shown to be higher at follicular phase when compared to luteal phase of the menstrual cycle. In conclusion, this thesis demonstrated that oviductal epithelial cell membrane proteins bind to the human spermatozoa and protect them from ROS-induced damages in terms of motility, membrane integrity, and DNA integrity. sFUT5 mediates the spermatozoon-oviductal epithelial cell interaction and the beneficial effects of such interaction on the fertilizing ability of spermatozoa. Results from this study provide the potential use of sFUT5-interacting proteins to enhance the fertilization ability of human spermatozoa by protecting them from oxidative stress. / published_or_final_version / Obstetrics and Gynaecology / Doctoral / Doctor of Philosophy

Abstract Several recent studies have indicated that radiofrequency electromagnetic fields (RFEMF) have an adverse effect on human sperm quality, which could translate to an effect on fertilization potential. The present study evaluated the effect of RF-EMF on spermspecific characteristics in order to assess the fertilizing competence of sperm. Highly motile human spermatozoa, were exposed for one hour to 900 MHz mobile phone radiation at a specific absorption rate (SAR) of 2.0 W/kg and examined at various times after exposure. The acrosome reaction was evaluated using flow cytometry. The radiation did not affect sperm propensity for the acrosome reaction. Morphometric parameters were assessed by computer assisted sperm analysis (CASA). Significant reduction in sperm head area (9.2 ± 0.7 μm2 vs. 18.8 ± 1.4 μm2) and acrosome percentage of the head area (21.5 ± 4% vs. 35.5 ± 11.4%) were reported among exposed sperm compared with unexposed controls. Sperm–zona binding was assessed directly after exposure using the hemizona assay (HZA). The mean number of zona-bound sperm of the test hemizona and controls was 22.8 ± 12.4 and 31.8 ± 12.8 (p<0.05), respectively. This study concludes that while RF-EMF exposure did not adversely affect the acrosome reaction, it had a significant effect on sperm morphometry. In addition a significant decrease in sperm binding to the hemizona was observed. These results could indicate a significant effect of RF-EMF on sperm fertilisation potential.

Recent reports suggest that mobile phone radiation may diminish male fertility. However, the effects of this radiation on human spermatozoa are largely unknown. The present study examined effects of the radiation on induction of apoptosisrelated properties in human spermatozoa. Ejaculated, densitypurified, highly motile human spermatozoa were exposed to mobile phone radiation at specific absorption rates (SARs) of 2.0 and 5.7 W/kg. At various times after exposure, flow cytometry was used to examine caspase 3 activity, externalization of phosphatidylserine (PS), induction of DNA strand breaks, and generation of reactive oxygen species. Mobile phone radiation had no statistically significant effect on any of the parameters studied. This suggests that the impairment of fertility reported in some studies was not caused by the induction of apoptosis in spermatozoa.

No description available.

Semen from 70 males of the White Leghorn and Broad Breasted White parental breeds and their F1 generation of reciprocal crosses was used to artificially inseminate over 500 females. Some 6,000 eggs obtained from the inseminated females were examined for fertility. [...]

No description available.

Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1990. / Includes bibliographical references (leaves 97-104) / Microfiche. / ix, 109 leaves, bound ill. 29 cm