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  • Küçük Resim
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    The effect of estrous cycle on oxidant and antioxidant parameters in dairy cows
    (Kafkas Üniversitesi Veteriner Fakültesi, 2014) Aydilek, Nurettin; Varışlı, Ömer; Selek, Şahabettin; Korkmaz, Ömer; Atlı, Mehmet Osman; Taşkın, Abdullah
    Reactive oxygen species have fundamental roles in reproductive functions. To comprehensively evaluate the relation between reactive oxygen species and infertility, physiological variations across the estrous cycle in healthy cows have to be known. For this purpose 25 healthy multiparous Holstein dairy cows having regular estrous cycles were used. The estrous cycles were synchronized by ovsynch protocol. Oxidant [lipid hydroperoxide (LOOH), total oxidant status (TOS), oxidative stress index (OSI)], antioxidant parameters [total antioxidant status (TAS), total free sulfhydryl groups (SH), ceruloplasmin (CP), paraoxonase-1 (PON1), arylesterase (ARE), uric acid (UA)], lipid profile and progesterone levels were assayed at estrus, metestrus, diestrus and proestrus stages of the estrous cycle in the plasma samples. The plasma levels of oxidant (LOOH, TOS and OSI) and antioxidant (TAS, SH and UA) parameters were significantly decreased during the luteal phase compared to the follicular phase (at proestrus and at estrus) of the estrous cycle. There was also a significant positive correlation between TAS and TOS. The activity of PON1 and ARE significantly increased only at diestrus. Levels of high density lipoprotein, low density lipoprotein and total cholesterol elevated during the follicular phase (estrus) and declined during the luteal phase. In conclusion, oxidant/antioxidant status and lipid profile were affected by cyclic changes. Moreover, antioxidant defense system showed adaptive response to increased oxidative activities by occurring parallel increases and it may indicate that there is a dynamic balance between oxidant and antioxidant status during the estrous cycle in healthy cows.
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    Effect of long term heat stress and dietary restriction on the expression of small heat shock protein (sHSP) genes in rat liver tissue
    (2016) Güzeloğlu, Aydın; Aydilek, Nurettin; Bozkaya, Faruk; Kayış, Seyit Ali; Atlı, Mehmet Osman; Kaya, Mehmet Salih
    Amaç: Bu çalışmanın amacı uzun süreli sıcaklık stresi ve yem kısıtla-masının rat karaciğer dokusunda bazı küçük ısı şoku protein (sHSP) genlerinin mRNA düzeyindeki ekspresyonu düzeyleri üzerine etkisi-nin araştırılmasıdır. Gereç ve Yöntem: Bu amaçla on haftalık yaştaki toplam 24 Spra-gue-Dawley rat 4 gruba ayrıldı. Grup I ve Grup II'deki ratlar 22°C'lik ortam sıcaklığında, Grup III ve Grup IV'teki ratlar ise 38°C'lik ortam sıcaklığında tutuldu. Grup I ve III'teki ratlar ad libitum olarak beslen-di, Grup II ve IV'teki ratlara ise ad libitum grupların tükettiği yemin %60'ı kadar yem verildi. Uygulama 9 hafta sürdürüldükten sonra karaciğer doku örnekleri alınarak sıvı azot içerisinde donduruldu ve RNA izolasyonuna kadar muhafaza edildi. Doku örneklerinden total RNA izole edildikten sonra HspB1, HspB5, HspB6, Hsp10 ve Hsp11 genlerinin ekspresyon düzeyleri gerçek zamanlı nicel polimeraz zin-cir reaksiyonu (RT-qPCR) yöntemi ile incelendi.Bulgular: Sıcaklık stresi HspB2, HspB8 ve Hsp70 genlerinin ekspres-yonunu önemli ölçüde arttığı, HspB1, HspB5, HspB6, Hsp10 ve Hsp11 genlerinin ekspresyonunu ise etkilemediği belirlendi. Yem kısıtla-ması HspB6 geninin expresyonunu arttırırken HspB1, HspB2, HspB5, HspB8 HspB10, HspB11 ve Hsp70 genlerinin ekspresyonunu etkile-mediği gözlendi. Uygulamalar arasında interaksiyon gözlenmedi.Öneri: Çalışmanın sonuçları uzun süreli sıcaklık stresinin rat kara-ciğer dokusundaki sHSP genlerinin ekspresyonlarını değişik düzey-lerde etkilediğini, yem kısıtlamasının sHSP genlerinin sıcaklık stresi tarafından etkilenen ekspresyonlarını değştirmediğini göstermiştir.
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    Effects of long-term heat stress and dietary restriction on the expression of genes of steroidogenic pathway and small heat-shock proteins in rat testicular tissue
    (Blackwell Publishing Ltd, 2017) Bozkaya, Faruk; Atlı, Mehmet Osman; Güzeloǧlu, Aydın; Kayış, Seyit Ali; Yıldırım, Mehmet Erol; Kurar, Ercan; Yılmaz, Rahşan; Aydilek, Nurettin
    The aim was to investigate the effects of long-term heat stress and dietary restriction on the expression of certain genes involving in steroidogenic pathway and small heat-shock proteins (sHSPs) in rat testis. Sprague Dawley rats (n = 24) were equally divided into four groups. Group I and II were kept at an ambient temperature of 22°C, while Groups III and IV were reared at 38°C for 9 weeks. Feed was freely available for Group I and Group III, while Group II and Group IV were fed 60% of the diet consumed by their ad libitum counterparts. At the end of 9 weeks, testicles were collected under euthanasia. Total RNA was isolated from testis tissue samples. Expression profiles of the genes encoding androgen-binding protein, follicle-stimulating hormone receptor, androgen receptor, luteinising hormone receptor, steroidogenic acute regulatory protein (StAR), cyclooxygenase-2 and sHSP genes were assessed at mRNA levels using qPCR. Long-term heat stress decreased the expression of StAR and HspB10 genes while dietary restriction upregulated StAR gene expression. The results suggested that long-term heat stress negatively affected the expression of StAR and HspB10 genes and the dietary restriction was able to reverse negative effect of heat stress on the expression of StAR gene in rat testis.
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    Expression profiles of interferon-tau stimulated genes (ISGs) in peripheral blood leucocytes (PBLs) and milk cells in pregnant dairy cows
    (Kafkas Üniversitesi Veteriner Fakültesi, 2014) Köse, Mehmet; Görgülü, Mehmet; Kaya, Mehmet Salih; Aydilek, Nurettin; Bozkaya, Faruk; Bayrıl, Tahir; Kurar, Ercan; Kıyma, Zekeriya; Güzeloğlu, Aydın; Atlı, Mehmet Osman
    In previous reports, it was indicated that measurement of activity of Interferon-tau Stimulated Genes (ISGs) in Peripheral Blood Leucocytes (PBLs) may be used as an alternative early pregnancy detection method in dairy cows. However, there are no data showing the expression profiles of ISGs in other body fluids containing leucocytes such as milk. In the present study, it was hypothesized that leucocytes in milk samples may reflect the increases in expression profiles of ISGs as shown in PBLs. For this purpose, nine pregnant lactating Holstein cows were used. Insemination day was accepted as day zero (day 0). Blood and milk samples were collected on day 0 and 18 after insemination for cell isolation. Total RNA was extracted from isolated cells and converted to cDNA. Steady state levels of Interferon-tau Stimulated Gene 15 (ISG15), Myxovirus (influenza virus) resistance 1 (MX1) and 2 (MX2) mRNA transcripts were assayed by using real- time reverse transcriptase PCR. Relative Expression Software Tool (REST2009) was used for statistical analyses. There was no statistical significant difference for expression levels of ISG15, MX1 and MX2 mRNAs between days 0 and 18 in milk samples. However, when compared to day 0, levels of ISG15 and MX2 transcripts were increased 6.97±0.68 fold and 5.84±1.27 fold on day 18 in PBLs in pregnant cows, respectively (P<0.05). According to this result, it may be suggested that milk cells are not suitable measurement of expression profiles of ISGs to detect early pregnancy in lactating dairy cows.
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    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.
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    Impacts of specific cryoprotectants on sperm freezing and relationships between cryodamage and oxidation stress parameters in awassi ram sperm
    (Cryo Letters, 2021) Varışlı, Ömer; Erat, Serkan; Bozkaya, Faruk; Aydilek, Nurettin; Taşkın, 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
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    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.
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    Toll-like receptor 2 and 4 expression in the bovine corpus luteum during the different stages of the estrous cycle
    (Brazilian Coll Animal Reproduction, 2017) Atli, Mehmet Osman; Kose, Mehmet; Kaya, Mehmet Salih; Aydilek, Nurettin; Guzeloglu, Aydin; Wiltbank, Milo C.
    The aim of this study was to elucidate the presence of components of the innate immune system in the bovine corpus luteum (CL) by detecting the expression and cell-specific localization of TLR2 and TLR4 during different stages of the estrous cycle in a control study design. Bovine CL samples were collected from a local slaughterhouse and assigned to three groups as follows: developing CL (dCL; n = 6, approx. days 3-6), mature CL (mCL; n = 5, approx. days 8-12), and regressing CL (rCL; n = 5, approx. days 17-19). An upregulation of TLR2 mRNA was detected only in rCL (P < 0.05). Localization of the TLR2 protein was particularly apparent in luteal cells and a prominent immunofluorescent signal corresponding to TLR2 was detected only in rCL. TLR4 mRNA were higher in mCL and rCL compared to dCL (P < 0.05). The presence of the TLR4 protein in bovine CL was clearly detected in the luteal cells of both mCL and rCL. The results of this study suggest a role for TLRs in the development, maintenance, and regression of bovine CL. TLR signaling mediated pathway in luteal cells may involve in the regression of CL via regulation of TLR2 and TLR4.