Decrease in prosaposin in spermatozoon is associated with polychlorinated biphenyl exposure

Polychlorinated biphenyls (PCBs) are a class of ubiquitous persistent organic pollutants and they have been associated with declining male fertility. In the present study, we aimed to determine the responsiveness of prosaposin (Psap) expression to PCB exposure. Male C57 mice were exposed to PCB mixture (Aroclor 1254) of environmental related doses by oral gavage. After exposure for 50 days, the expression of Psap was significantly decreased by PCB exposure in epididymides and epydidymal spermatozoa, but not in testis. The Psap abundance in sperm was decreased in a dose-dependent manner. Benchmark dose modeling revealed the 95% lower confidence limit on the benchmark dose (BMDL) and Benchmark Dose (BMD) for Psap reduction were 1.25 and 8.89 μg/kg Aroclor 1254, and for sperm motility reduction were 11.85 and 61.9 μg/kg Aroclor 1254. The depressed Psap level also showed a significant correlation (P<0.01, r=-0.531) with PCB accumulation in liver. In men with detectable PCB exposure in semen, Psap expression in sperm was significantly decreased whereas the semen parameters were unaffected. Linear regression showed that a negative association between total PCB level in seminal plasma and Psap level in ejaculated spermatozoa (P<0.05, r=-0.396). In conclusion, our data suggested that the abundance of Psap in sperm sample may be a sensitive endpoint to predict PCB exposure.