The deleterious toxic effects of bifenthrin on male fertility.

Bifenthrin (BF), a broad-spectrum synthetic pyrethroid insecticide, has been generally used to eradicate harmful insects. However, according to the U.S. EPA, BF has been classified as a "Class C" carcinogenic ingredient. Furthermore, a previous study reported that BF was considered as endocrine-disrupting chemicals and causes reproductive toxicity in mammals. Despite the various effects of BF, there is a scarcity of studies about its adverse effects on male fertility. Therefore, this study was conducted to determine the effects of BF on sperm functions at various concentrations (0.1, 1, 10, and 100 μM), including a control. Sperm motility and kinematics, capacitation status, intracellular ATP levels, cell viability, PKA activation, and protein tyrosine phosphorylation were measured. Moreover, fertilization and early embryonic development were examined through in vitro fertilization. Results showed that sperm motility and kinematic parameters were significantly decreased at a high BF concentration. Consequently, the sperm capacitation status exhibited significant alteration according to the treatment concentration. Intracellular ATP levels were significantly decreased at 10 and 100 μM treatment concentrations. Moreover, the levels of phospho-PKA substrates were significantly increased in a dose-dependent manner. In contrast, the levels of phospho-tyrosine substrates were significantly decreased at 10 and 100 μM treatment concentrations. BF treatment also diminished the rate of blastocyst formation. Altogether, our results demonstrated that BF causes detrimental effects on sperm function and can influence fertilization. Therefore, our study results might be helpful in understanding the adverse effects of BF on male fertility.