Protective effect of Scrophularia striata combined with trehalose and cysteine added to diluents on cryopreservd goat epididymal sperm

Abstract

Objective: To evaluate antioxidant effects of Scrophularia (S.) striata ethanol extract, trehalose and cysteine added to diluents on cryopreserved goat epididymal sperms.Methods: Motility and standard motion parameters of sperm were assessed by using computer assisted sperm motility analysis system. Sperm viability was evaluated by eosin-nigrosin staining method. Hypo-osmotic swelling test was used to evaluate membrane health. Thiobarbituric acid testing was used to measure malondialdehyde (MDA) concentrations. To assess DNA fragmentation, sperm chromatin dispersion test was used. In Experiment 1, treatments consisting of basal Tris diluent supplemented with 25, 50 or 100 μg/mL of S. striata ethanol extract gave the best concentration to the freezing diluents. Experiment 2 was carried out to compare the best concentration of S. striata ethanol extract (50 μg/mL) resulting from the first experiment with 150 mM trehalose and/or 5 mM cysteine alone or in combination.Results: S. striata ethanol extract (50 μg/mL) significantly increased sperm viability, motility and progressive motility and at the same time decreased MDA concentration and DNA fragmentation compared to other treatments (P<0.05). In addition, all treatment groups resulted in viability, membrane health, total motility, progressive motility, curvilinear velocity, straight-line velocity higher and MDA lower compared to the control group (P<0.05). Acrosome integrity was significantly higher in 50 μg/mL of S. striata ethanol extract combined with cysteine, trehalose, or cysteine+trehalose groups than those in the control, trehalose, cysteine, and 50 μg/mL of S. striata ethanol extract groups (P<0.05). Regarding DNA, extenders supplemented with 50 μg/mL of S. striata ethanol extract, 50 μg/mL of S. striata ethanol extract+trehalose, and 50 μg/mL of S. striata ethanol extract+trehalose+cysteine were superior to other treatments.Conclusions: Adding 50 μg/mL of S. striata ethanol extract alone or in combination with trehalose and cysteine can improve the quality of cryopreserved epididymal sperms of goats.