Exposure in utero to 2,2',3,3',4,6'-hexachlorobiphenyl (PCB 132) impairs sperm function and alters testicular apoptosis-related gene expression in rat offspring.
Toxicity of the polychlorinated biphenyls (PCBs) depends on their molecular structure. Mechanisms by prenatal exposure to a non-dioxin-like PCB, 2,2',3,4',5',6-hexachlorobiphenyl (PCB 132) that may act on reproductive pathways in male offspring are relatively unknown. The purpose was to determine whether epididymal sperm function and expression of apoptosis-related genes were induced or inhibited by prenatal exposure to PCB 132. Pregnant rats were treated with a single dose of PCB 132 at 1 or 10 mg/kg on gestational day 15. Male offspring were killed and the epididymal sperm counts, motility, velocity, reactive oxygen species (ROS) generation, sperm-oocyte penetration rate (SOPR), testicular histopathology, apoptosis-related gene expression and caspase activation were assessed on postnatal day 84. Prenatal exposure to PCB 132 with a single dose of 1 or 10 mg/kg decreased cauda epididymal weight, epididymal sperm count and motile epididymal sperm count in adult offspring. The spermatozoa of PCB 132-exposed offspring produced significantly higher levels of ROS than the controls; ROS induction and SOPR reduction were dose-related. In the low-dose PCB 132 group, p53 was significantly induced and caspase-3 was inhibited. In the high-dose group, activation of caspase-3 and -9 was significantly increased, while the expressions of Fas, Bax, bcl-2, and p53 genes were significantly decreased. Gene expression and caspase activation data may provide insight into the mechanisms by which exposure to low-dose or high-dose PCB 132 affects reproduction in male offspring in rats. Because the doses of PCB 132 administered to the dams were approximately 625-fold in low-dose group and 6250-fold higher in high-dose group than the concentration in human tissue levels, the concentrations are not biologically or environmentally relevant. Further studies using environmentally relevant doses are needed for hazard identification.
Hsu
Ping-Chi
PC
Department of Safety, Health and Environmental Engineering, National Kaohsiung First University of Science and Technology, Kaohsiung, Taiwan.
Pan
Min-Hsiung
MH
Li
Lih-Ann
LA
Chen
Cheng-Jung
CJ
Tsai
Shinn-Shyong
SS
Guo
Yueliang Leon
YL
D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D007274:Injections, Intraperitoneal; D008297:Male; D008954:Models, Biological; D011078:Polychlorinated Biphenyls / Q000008:administration & dosage / Q000633:toxicity*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013094:Spermatozoa / Q000187:drug effects* / Q000502:physiology; D013737:Testis / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D016159:Tumor Suppressor Protein p53 / Q000235:genetics; D051028:bcl-2-Associated X Protein / Q000235:genetics; D019014:fas Receptor / Q000235:genetics
C494828:Bax protein, rat; C491898:Fas protein, rat; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D019014:fas Receptor; C094859:2,2',3,3',4,6'-hexachlorobiphenyl; D011078:Polychlorinated Biphenyls; D053148:Caspase 3; D053453:Caspase 9