Reproductive Toxic Effects And Mechanisms Of PFQA On Male Rang Nisromaculata

Perfluorooctanoic acid?PFOA?is a type of synthetic perfluorinated compounds?PFCs?.It is widely distributed in the environment because it is toxic,persistent and difficult to be degradated.It is of great significance for amphibian species conservation to investigate the reproductive effects of PFOA on male frogs.In the present study,PFOA was regarded as target pollutant and the male Rana nigromaculata were regarded as research object.Male Rana nigromaculata were exposed to PFOA for 14 days in vivo.This study aimed to disclose the reproductive effects and mechanisms of PFOA on male Rana nigromaculata.The results showed that the sperm activities and the numbers of sperm were significantly decreased and the percentages of sperm deformity were significantly increased after exposure to 0.01-1 mg/L PFOA for 14 days.The numbers of sperm and sperm motility were decreased by 43.7%and 55.1%,respectively,and the percentages of sperm deformity were increased by 1.84-fold.The activities of ATPase that were closely related to spermatogenesis in the testis of male Rana nigromaculata were detected.The results showed that the activities of Na⁺K⁺-ATPase,Ca²⁺-ATPase and Ca²⁺Mg²⁺-ATPase were all significantly increased with the increase of exposure concentrations of PFOA.The activities of Na⁺K⁺-ATPase,Ca²⁺-ATPase and Ca²⁺Mg²⁺-ATPase were increased by 2.05-,1.97-and 1.97-fold,respectively,after exposure to 1mg/L PFOA.These results showed that the spermatogenesis and the sperm maturation of male Rana nigromaculata were disturbed due to the imbalance of ion homeostasis in the testis.The contents of testosterone were significantly decreased with the increasing of PFOA concentrations,while the contents of estradiol were significantly increased after exposure to PFOA.The contents of testosterone were decreased by 80.6%and the contents of estradiol were increased by 1.29-fold after exposure to 1mg/L PFOA.The gene expression levels of P450arom and steroidogenic factor 1?SF-1?were all increased,which indicated that PFOA could disturb hormone synthesis by regulating gene expression of P450 and SF-1.Ultrastructural changes were observed in the testis of male Rana nigromaculata after exposure to PFOA.Vacuolation and scattering of spermatogenic-sertoli cell,and incomplete cell structure;mitochondria swelling,dilatation of endoplasmic reticulum,deformation of nucleus,etc.in spermatogenic-sertoli cell,vacuolated sperm and abnormal sperm tail were observed.The results showed that the reproductive toxic effects were induced in the testis of male Rana nigromaculata by PFOA.The oxidation and antioxidant parameters in the testis of male Rana nigromaculata were also detected.The results showed that the levels of reactive oxygen species?ROS?,Methane Dicarboxylic Aldehyde?MDA?contents,superoxide dismutase?SOD?contents,catalase?CAT?contents,Glutathione?GSH?contents,succinate dehydrogenase?SDH?contents and lactate dehydrogenase?LDH?contents were all significantly increased,the activities of glutathione S-transferase?GST?enzyme were significantly decreased.The levels of ROS and MDA contents were increased by2.91-and 3.51-fold,respectively,after exposure to 1mg/L PFOA.The results showed PFOA could induce lipid peroxidation and damage homeostasis of antioxidant system in the testis of Rana nigromaculata.Western Blotting analysis showed that the protein levels of Bax and Caspase 3,8,7 were all significantly increased,while the protein expression levels of Bcl-2 were significantly decreased after exposure to PFOA.The above results showed that PFOA induced cell apoptosis in the testis of Rana nigromaculata by mitochondrial apoptosis pathway.In addition,the expression protein levels of Chop were significantly increased after exposure to PFOA,which showed that the endoplasmic reticulum apoptosis pathway was also involed in the testis of Rana nigromaculata.In summary,PFOA caused the decreases of sperm activity and sperm numbers,the increase of sperm deformity percentage.These toxic effects were associated with the imbalance of ion homeostasis,sex hormone disorder,oxidative stress and cell apoptosis in the testis of Rana nigromaculata.This study illustrated the reproductive toxic effects and mechanisms of PFOA on amphibian.It can provide the basic material and scientific basis for the study of animal species protection.