Effects of reduced glutathione and catalase on the kinematics and membrane functionality of sperm during liquid storage of ram semen

Effects of reduced glutathione and catalase on the kinematics and membrane functionality of sperm during liquid storage of ram semen

D.R. Câmara, M.M.C. Mello-Pinto, L.C. Pinto, O.O. Brasil, J.F. Nunes, M.M.P. Guerra,

Department of Veterinary Medicine, Federal University of Alagoas, Fazenda São Luiz, s/n, Zona Rural de Viçosa, Viçosa-AL, Brazil; Northeast Biotechnology Network, Brazil; Laboratory of Sheep and Goat Semen Technology, Ceará State University, Av. Paranjana, 1700 – Campus do Itaperi, Fortaleza-CE, Brazil; Laboratory of Andrology, Department of Veterinary Medicine, Federal Rural University of Pernambuco, R. Dom Manoel de Medeiros, s/n, Dois Irmãos, Recife-PE, CEP 52171-900, Brazil

The objective of this study was to evaluate the effects of reduced glutathione (GSH) and catalase (CAT) supplementation on the kinematics and membrane functionality of sperm during the liquid storage of ram semen, cooled at 5 °C, for up to 24 h. Semen samples from four rams were pooled, diluted with Tris-egg yolk extender without antioxidants (control) or supplemented with either CAT (100, 200, and 400 U/mL) or GSH (100, 200, and 400 mM) at a final concentration of 50 × 10⁶ sperm/mL. Sperm kinematics, which was analyzed by computer-assisted sperm analysis (CASA), and membrane functionality, which was analyzed using the hypo-osmotic swelling test (HOST), were determined after the addition of the semen samples at different processing times (fresh/diluted, 1.5, 6, 12, and 24 h, at 5 °C). No significant differences were recorded in the kinematics or membrane functionality between treatments at different times. The supplementation of diluents with 100 and 200 U/mL of CAT prevented the harmful effects of cooling on total sperm motility. No significant differences were observed in progressive sperm motility throughout processing, regardless of the treatment and time of evaluation. Supplementation with 400 mM GSH resulted in an earlier reduction (P < 0.05) of total sperm motility, a decrease in rapid sperm rate and a reduction in curvilinear velocity during incubation, at 5 °C. The cooling induced a reduction (P < 0.05) in the percentage of sperm with a functional plasma membrane (HOST), especially after 1.5 h of incubation. Based on the results of the present study, the addition of CAT (100 and 200 U/mL) reduced the deleterious effects of cooling on total motility in ram sperm maintained at 5 °C for 24 h, although it did not affect the functionality of the sperm membranes. However, the addition of 400 mM GSH caused negative effects on the velocity parameters of the sperm.

doi:10.1016/j.smallrumres.2011.05.010