Objective To investigate toxic effects of chlordecone on sperm cells of Caenorhabditis elegans (C. elegans) and its relationship with oxidative stress injury.
Methods The nematodes of stage L1 were exposed to chlordecone at four dosages (0.02, 0.2, 2 and 20 μg/L) for 48 hours and those of blank control were treated with M9 solution; then the number of offspring was counted and the generation time was observed for all the nematodes. The level of reactive oxygen species (ROS) in the nematodes was detected with 5-(6)-chloromethyl-2′,7′-dichlorodihydrofluorescein diacetate (CM-H2DCFDA) probe. The fluorescence intensity of distal tip cells (DTC) of JK2868 nematodes was observed with fluorescence microscopy. The number of gonadal mitosis was counted after dianamidophenylindole (DAPI) staining. The sperm deformity rate and in vitro activation rate of the nematodes were determined with microscopic observation.
Results The number of C. elegans progeny in the high-dose chlordecone group was 255.00 ± 13.72 and significantly higher than that in the control group (335.60 ± 21.31); the generation time of the high-dose chlordecone group was 69.60 ± 1.96 hours and significantly longer than that of the control group (55.80 ± 1.94 hours) (both P < 0.05). Compared with those of the control group, the level of ROS in the nematodes was higher but the fluorescence intensity in DTC was lower significantly for the nematodes exposed to moderate and high dose chlordecone (both P < 0.05). In comparison with those in the control group, decreased number of germ cells in the mitotic area (47.90 ± 5.42 vs. 87.90 ± 3.75), increased rate of sperm abnormality (84.00% ± 7.29% vs. 12.70% ± 1.16%) and decreased rate of sperm activation in vitro (8.70% ± 2.41% vs. 77.00% ± 9.82%) were observed in the nematodes exposed to 20.00 μg/L chlordecone.
Conclusion Oxidative stress injury may be an important mechanism of genotoxicity induced by chlordecone in Caenorhabditis elegans.
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