| Summary: | 碩士 === 國立高雄第一科技大學 === 環境與安全衛生工程研究所 === 102 === Abstract
Background: In Taiwan in 1979, large-scale event of accidental exposure to polychlorinated biphenyls (PCBs) and polychlorinated dibenzofurans (PCDFs) owing to ingestion of cooking rice oil. This episode was referred to as "Yu-cheng" (“oil-disease” in Chinese) exposure. A past study of the young men born to Yu-cheng women exposed to PCBs/PCDFs showed decreased sperm function, such as sperm count, and motility. Flow cytometry (FCM) is a tool with great potential for performing both qualitative and quantitative analyses based on simultaneous measurements of structural and functional parameters of individual cells. In combination with fluorescent dyes, we performed concomitantly four well-defined cytofluorometric assays to assess sperm mitochondrial membrane potential (MMP), reactive oxygen species (ROS) generation, and chromatin DNA integrity in semen samples from Yu-cheng young men and their controls.
Objective: The aim of this study was to establish correlation between the changes of sperm functions using FCM and the quality of sperm evaluated using conventional light microscopy analysis to evaluate among Yu-Cheng young men and control group.
Methods: A total of 35 young men born to Yu-cheng women exposed to PCBs/PCDFs in 1979-1982 and 15 graduate students from a university in south Taiwan. Including the graduate students, a total of 50 participants agree to complete questionnaires including basic information, lifestyle, and sexual function and donate their semen sample. We measured the parameters of semen quality, such as semen volume, sperm concentration, motility, and morphology in according with WHO guideline. All interviews, examinations, and laboratory tests were performed in a
blinded fashion. We further analysed sperm MMP, ROS generation and sperm chromatin structure analysis (SCSA) using FCM. Finally, we evaluated the relationships between sperm functions using multiple linear regressions.
Results: Compared with 15 control subjects, the 35 Yu-cheng young men were about the same age, similar in body weight, body mass index, age of first ejaculation or nocturnal emission, frequency of erection per day, abstinence time from ejaculation before study, and alcohol drinking. We found that body height and education were significantly lower and smoking rate was significantly higher among Yu-cheng group compared to the control group. Semen volume, sperm concentration, motility, and normal morphology were all significantly reduced in Yu-Cheng group. Sperm abnormal morphology, including head defect and tail defect as well as prevalence rate of asthenozoospermia were significantly increased in Yu-Cheng group. No significant differences were found for MMP, sperm H2O2 generation, and DFI. The percentage of sperm with excessive O2-. generation and the intensity level for sperm O2-. were significantly increased in Yu-cheng group than the control group. After adjusting for age, body mass index, smoking, alcohol drinking and hot bath, it was found that the decrease in sperm motility (β = -0.45, p = 0.0014) and normal morphology (β = -0.29, p < 0.0001) was inversely associated with the percentage of sperm with excessive O2-. generation, respectively. The intensity level of sperm O2-. was inversely with the sperm motility (β = -0.05, p = 0.0128) and normal morphology (β = -0.04, p = 0.0003), respectively.The percentage of sperm with excessive H2O2 generation was found to be inversely correlated with sperm normal morphology (β = -2.60, p = 0.0002).
Conclusion: Spermatozoa of PCBs/PCDFs prenatally exposed Yu-cheng young men have decrease of semen volume, sperm concentration, motility, and increasing sperm
ROS generation. It might be associated with sperm count, motility and morphology
via sperm excessive ROS generation. The detail mechanisms still need to be clarified.
Key words: PCBs、PCDFs, Yu-Cheng, Flow cytometry, prenatal exposure, Semen quality.
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