Yazar "Varisli, Omer" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • [ X ]
    Öğe
    Comparison of cryoprotective effects of iodixanol, trehalose and cysteamine on ram semen
    (Elsevier, 2013) Cirit, Umut; Bagis, Haydar; Demir, Kamber; Agca, Cansu; Pabuccuoglu, Serhat; Varisli, Omer; Clifford-Rathert, Charlotte
    This study was conducted to improve cryosurvival of electroejaculated (EE) ram semen in the presence of iodixanol (OptiPrep (TM)), trehalose or cysteamine. A tris-based extender was used to prepare 12 extenders containing OptiPrep (TM) (Op), trehalose (Tr) or cysteamine (Cy) alone, or different combinations of these compounds. Extenders were designated as follows: Tris (control), Op1.25 (1.25% Op, v/v), Op2.5 (2.5% Op, v/v), Op5 (5% Op, v/v), Tr50 (50 mM Tr), Tr100 (100 mM Tr), Cy (5 mM Cy), OpTr (2.5% Op and 100 mM Tr), OpCy (2.5% Op and 5 mM Cy), TrCy (100 mM Tr and 5 mM Cy), OpTrCy1 (2.5% Op, 100 mM Tr and 5 mM Cy) and OpTrCy2 (1.25% Op, 50 mM Tr and 2.5 mM Cy). A two-step dilution was used and glycerol was added at 5 degrees C in the second step. Diluted samples were equilibrated for 1 h, loaded in 0.25 mL straws and frozen in a programmable freezing machine. Supplementation of 5% OptiPrep (TM) significantly protected post-thaw progressive motility, membrane integrity, acrosomal integrity and morphological damages. Trehalose supplementation protected membrane integrity of ram sperm; however, it did not help post-thaw motility and morphology. Supplementation of 5 mM cysteamine had detrimental effect on cryosurvival of EE ram semen. These results demonstrate that the supplementation of iodixanol increases the cryosurvival of EE ram semen in a dose-dependent manner. (c) 2013 Elsevier B.V. All rights reserved.
  • [ X ]
    Öğe
    IMPACTS OF SPECIFIC CRYOPROTECTANTS ON SPERM FREEZING AND RELATIONSHIPS BETWEEN CRYODAMAGE AND OXIDATION STRESS PARAMETERS IN AWASSI RAM SPERM
    (Cryo Letters, 2021) Varisli, Omer; Erat, Serkan; Bozkaya, Faruk; Aydilek, Nurettin; Taskin, Abdullah
    BACKGROUND: The role of oxidative stress during cryoprotectant treatment has received little attention. OBJECTIVE: To assess the effects of different cryoprotectants and discover relationships between cryodamage and oxidative stress parameters on Awassi ram sperm. MATERIALS AND METHODS: The sperm samples diluted with Salamon's tris-citrate (TRIS) containing 20% centrifuged egg yolk and 0.5, 1.0 or 1.5 M Glycerol (Gly), methanol (M), 2-methoxyethanol (2-ME), dimethylacetamide (DMA) and 1.2 propanediol (PR). After 2 h of equilibration at +4 degrees C, the sperm samples were frozen in liquid nitrogen vapour and stored. RESULTS: The best post-thaw motility (43.3%, 41.7%) of sperm was achieved when protected with 0.5 and 1.0 M glycerol. Arylesterase and ceruloplasmin parameters were significantly different after equilibration, whereas sulfhydryl groups were significantly different after freezing in their respective groups (P< 0.05). CONCLUSION: The increased use of glycerol caused greater loss of motility. The role of oxidative stress in freezing was also found to be limited.
  • [ X ]
    Öğe
    RELATIONSHIP BETWEEN TOXICITY OF CRYOPROTECTANTS, OSMOTIC AND OXIDATIVE STRESSES IN AWASSI RAM SPERM
    (Cryo Letters, 2022) Varisli, Omer; Bozkaya, Faruk; Aydilek, Nurettin; Taskin, Abdullah
    BACKGROUND: The relationship between the toxicity of cryoprotectants and their osmotic and/or oxidative stresses remains to be further investigated. OBJECTIVE: To investigate the toxic effects of different cryoprotectants and osmotic stress on Awassi ram sperm and to determine the relationship between oxidative and antioxidative status of the sperm. MATERIALS AND METHODS: Pooled sperm samples were exposed to sucrose solutions of different concentrations (75 to 900 mOsm) and isosmotic condition (290-325 mOsm) was re-established by adding HEPES buffered Tyrode's lactate. Sperm samples were mixed with 0.5, 1.0 and 1.5 M of glycerol, methanol, 2-methoxyethanol, dimethylacetamide or 1,2-propanediol for 5 min and returned to isosmotic condition. Sperm samples were exposed to cryoprotectants at 4 degrees C for 2 hours and isosmotic conditions were re-established. Motility, viability, acrosome integrity and oxidative or antioxidative parameters were determined. RESULTS: Treatment with hypo- or hyperosmotic sucrose solution reduced motility and viability without affecting acrosome integrity. The addition and removal of glycerol and dimethylacetamide (1.0 or 1.5 M) decreased sperm motility, while cryoprotectants had no effect on viability except for 1.5 M glycerol. Chilling significantly reduced the motility and viability of the sperm, but not the acrosome integrity. Rapid addition or removal of cryoprotectants also did not affect the acrosome integrity. Cryoprotectants changed only the ceruloplasmin level, while there were significant post-chilling differences in lipid hydroperoxide, paraoxonase and ceruloplasmin levels. CONCLUSION: Cryoprotectants without other additives have limited protection and glycerol can be toxic to spermatozoa. The oxidative stress plays a role in cryoprotectant toxicity and chilling stress.