Veterinarija ir Zootechnika

Chlorpyrifos (CPF), a widely used broad-spectrum pesticide, has been shown to affect significantly fertility outputs. However, there is limited knowledge concerning the potential involvement of oxidative stress (OS) in CPF-induced sperm dysfunction in mature spermatozoa, and the optimal protection against the potential deleterious effects. This study aimed, on the one hand, to investigate the effects of CPF on sperm motility and to assess whether OS may be involved in CPF-induced toxicity in epididymal spermatozoa. On the other hand, it aimed to evaluate the effects of vitamin C and vitamin E, administered individually or in association. Epididymal sperm was collected from five Capra hircus testes and divided into five equal-volume aliquots, receiving different treatments: Control−, CPF, VitC+CPF, VitE+CPF and VitCE+CPF. Control− group was diluted in TRIS extender, while CPF group was exposed to CPF (50 µg/mL). The vitamin-treated groups were pre-incubated for 20 min with vitamin C (0.1 mg/mL), vitamin E (0.25 mg/mL), or their combination prior to CPF exposure. Sperm motility was assessed after 0, 30, and 60 min of storage at 37 °C using Computer Aided Sperm Analysis. Malondialdehyde (MDA) levels were measured at 30 min in each treatment by the thiobarbituric acid reactive substances (TBARS) assay and quantified at 535 nm. CPF exposure impaired significantly sperm kinetics; at 60 min, VSL decreased from 11.248 ± 0.209 µm/s in the Control− group to 5.051 ± 0.143 µm/s in the CPF group (P<0.0001). Also, progressive motility decreased in the CPF group (0.225 ± 0.084%) compared with the Control− group (4.146 ± 1.224%). VitCE+CPF improved significantly VSL (17.405 ± 0.185 µm/s vs CPF; P<0.0001). MDA levels were elevated significantly in the CPF group (2.261 ± 0.1076 nmol MDA/10^8 SPZ) compared with the Control− group (1.919 ± 0.1085 nmol MDA/10^8 SPZ; P=0.0354). VitCE+CPF resulted in the lowest MDA concentration (1.739 ± 0.1065 nmol MDA/10^8 SPZ vs CPF; P=0.003). The results showed that CPF affects mature spermatozoa potentially through lipid peroxidation. These effects could be mitigated by vitamins C and E, especially when they are associated.