Ayşe Eken

The effect of cysteine and glutathione on sperm and oxidative stress parameters of post-thawed bull semen.

The aim of this study was to determine the effects of antioxidants such as reduced glutathione (GSH) and cysteine in Laiciphose® extender on semen parameters, fertilizing ability, lipid peroxidation (LPO) level and glutathione peroxidise (GPx) activity of post-thawed bull semen. Totally 54 ejaculates of three bulls were used in the study. Five groups, namely; GSH (0.5 and 2 mM), cysteine (5 and 10 mM) and control group, were conducted to test the antioxidants in Laiciphose®. Insemination doses were processed that each 0.25-mL straw contained 15 x 10⁶ sperm. The addition of antioxidants did not present any significant effect on the percentages of post-thaw sperm morphology (acrosome and total abnormalities), subjective, CASA and progressive motilities, as well as sperm motility characteristics (VAP, VSL, VCL, LIN and ALH), compared to the control groups (P > 0.05). GSH 0.5mM (55.5±7.38%) and cysteine 10 mM (48±5.65%) led to lower rates of DNA damage, compared to control (P < 0.05). As regards to MDA level, cysteine at 10 mM dose gave the highest level (4.99±0.44 nmol/L) (P < 0.001). GPx activity was demonstrated to be higher level upon the addition of 5 mM cysteine when compared to the other groups (P < 0.05). With respect to fertility results based on 60-day non-returns, the supplementation of antioxidants did not present significant differences (P > 0.05). The results of this study may provide an useful information for the future studies in this area. So, further studies could be suggested to achieve better information in terms of the DNA damage and fertilizing capacity of bull sperm frozen with effective antioxidants.

Cytogenetic analysis of peripheral blood lymphocytes of hospital staff occupationally exposed to low doses of ionizing radiation

Ionizing radiation is known to induce mutations and cell transformations, predominantly by causing single-strand and double-strand DNA breakage, thereby leading to chromosome instability and carcinogenesis. The aim of this study was to evaluate genotoxic effects in hospital staff exposed to low-dose ionizing radiation in comparison with a selected control group, by using the cytokinesis-blocked micronucleus (CBMN) and sister chromatid exchange (SCE) tests in peripheral blood lymphocytes. The study included 40 exposed radiology staff and 30 control subjects. The frequency of micronuclei (MN) was significantly increased in radiation-exposed groups compared with control persons (p < 0.05). The frequency of SCE did not show any significant difference in the exposed individuals in comparison to the controls. Our results showed that low-level chronic occupational exposure to ionizing radiation causes an increase of MN frequency in chromosomes, even though the absorbed doses were below the permissible limits. Our studies indicate that the CBMN assay is considered to be sensitive test in contrast to SCE analysis to evaluate chromosomal damage induced by ionizing radiation.

Antioxidative effects of cysteamine, hyaluronan and fetuin on post-thaw semen quality, DNA integrity and oxidative stress parameters in the Brown Swiss bull

The aim of this study was to compare the effectiveness of antioxidants including cysteamine (2.5, 7.5 mm), hyaluronan (0.25, 1 mg ml−1) and fetuin (5, 10 mg ml−1) in the freezing of Brown Swiss bull semen. The best percentages of CASA motilities were achieved with 10 mg ml−1 of fetuin and 2.5 mm of cysteamine. For sperm morphology, 10 mg ml−1 of fetuin and 2.5 mm of cysteamine had better protective effects (P < 0.001). The results of hypo‐osmotic swelling test showed that the percentage values of membrane integrity in all the groups, excluding that supplemented with 5 mg ml−1 of fetuin, were higher than those of the control group (P < 0.001). Results obtained for the DNA damage of sperm cells demonstrated that 0.25 mg ml−1 of hyaluronan, and 2.5 and 7.5 mm of cysteamine led to lower rates of spermatozoa with damaged DNA, compared with the control group (P < 0.001). The maintenance of superoxide dismutase and glutathione peroxidase antioxidant activities following freeze‐thawing with 2.5 and 7.5 mm of cysteamine and 10 mg ml−1 of fetuin was demonstrated to be at a higher level in comparison with the control group (P < 0.001). Malondialdehyde formation was found to be lower in the groups supplemented with 0.25 mg ml−1 of hyaluronan and 7.5 mm of cysteamine after the freeze‐thawing process (P < 0.001).

Cryopreservation of bull sperm: Effects of extender supplemented with different cryoprotectants and antioxidants on sperm motility, antioxidant capacity and fertility results

The objectives of this study were to compare glycerol (G) and ethylene glycol (EG) at different concentrations and trehalose (T) or cysteine (C; with/without) in Tris extender for cryopreservation of bull semen. Twenty-four ejaculates obtained from three bulls were included in the study. Each ejaculate was divided into four equal aliquots and diluted using both of the Tris extenders with G (5% or 7%) or EG (3% or 5%). After that, each extenders were divided into three equal aliquots and diluted using both of the 5 mM C or 25 mM T, and control (without additives) was cooled to 4 ° C and frozen in 0.25 ml French straws. The addition of 3% and 5% EG without antioxidants resulted in the least Computer-Assisted Sperm motility Analysis (CASA) motility as compared with the other groups. Treatment with 25 mM T in 3% EG beneficially effected acrosome morphology as compared with the other groups. Also, treatment with 3% EG with 25 mM T and 5% EG resulted in a greater rate of total abnormalities. Treatment with 3% G yielded a slightly greater percentage of membrane integrity by Hypo-Osmotic Swelling Test (HOST) assessment than that of the other groups. Treatment with 3% EG with 5 mM C resulted in the greatest concentration of malondialdehyde (MDA). The glutathione peroxidase (GPx) antioxidant activity was increased in the C-treatment groups when compared to the other groups. Treatment with 5% EG and 5 mM C resulted in less chromatin damage and detrimental impacts on tail moment. Treatment with 5% EG led to greater non-return rates of inseminated cows. However, this result was not considered to be statistically important.

Induced antioxidant activity in hospital staff occupationally exposed to ionizing radiation

Abstract Purpose: Occupational exposure to low levels of ionizing radiation (IR) in radiology department staff may affect their antioxidant status. The aim of this study was to evaluate the oxidative stress parameters in radiology staff that are occupationally exposed to IR in a hospital setting. Materials and methods: The study population included 40 exposed radiology staff and 30 control subjects. The radiation doses of exposed staff ranged between 0.10 and 3.8 milligray (mGy) per month. The subjects’ antioxidant status was determined by measuring the activities of copper zinc-superoxide dismutase (CuZn-SOD), selenium dependent glutathione peroxidase (Se-GPx), catalase (CAT) enzymes, and the levels of malondialdehyde (MDA) in erythrocytes. Results: Our results showed that the activities of erythrocyte CuZn-SOD and Se-GPx enzymes observed for the radiation exposed group were significantly higher than in the controls. The activity of CAT enzyme and MDA levels were significantly lower in the exposed group than in the controls. Moreover, we investigated the influence of confounding factors on antioxidant enzymes or lipid peroxidation (LP), but we could not find any associations between them. Conclusions: Our study indicates the presence of stimulant effect of chronic low-dose radiation in exposed individuals, resulting in enhanced resistance to oxidative stress.

Association of GPX1 polymorphism, GPX activity and prostate cancer risk

Prostate cancer is the second most common cancer in men worldwide. Although the aetiology of this disease remains largely unclear, several lines of evidence suggest that oxidative stress plays a role in prostate carcinogenesis. The antioxidant enzyme glutathione peroxidase 1 (GPX1) is part of the enzymatic antioxidant defence, preventing oxidative damage to DNA, proteins and lipids by detoxifying hydrogen and lipid peroxides that may contribute to prostate cancer development. Some studies indicate an association between GPX1 Pro198Leu polymorphism and an increased risk of cancer. The purpose of the present study was to determine the possible association of GPX1 Pro198Leu polymorphism and erythrocyte GPX activity with the risk of developing prostate cancer and to clarify whether erythrocyte GPX activity levels were correlated with the GPX1 Pro198Leu genotype in the Turkish population. The GPX1 Pro198Leu genotype was determined in 33 prostate cancer patients and 91 control individuals. As evident from our results, there was no difference between genotype and/or allele frequencies in prostate cancer patients and controls. No significant difference was found in GPX1 genotype or allele frequency between aggressive and non-aggressive prostate cancer patients. It can be suggested with these findings that individual susceptibility of prostate cancer may be modulated by GPX1 polymorphism, but it needs further studies.

The effect of bovine serum albumin and fetal calf serum on sperm quality, DNA fragmentation and lipid peroxidation of the liquid stored rabbit semen

The aim of the present study was to determine the effects of the bovine serum albumin (BSA) and fetal calf serum (FCS) on sperm quality, DNA fragmentation and lipid peroxidation of liquid stored rabbit semen stored up to 72 h at 5 °C. Ejaculates were collected from five New Zealand male rabbits by artificial vagina and pooled at 37 °C following evaluation. Each pooled ejaculate was split into three equal experimental groups and diluted to a final concentration of approximately 40 × 10(6)sperm/ml (single step dilution), in an Eppendorf tube, with the Tris based extender containing BSA (5mg/ml), FCS (10%) or no additive (control) at 37 °C, cooled to 5 °C and stored for up to 72 h. The extender supplemented with BSA and FCS did not improve the percentages of motility and acrosomal abnormality during 48 h compared to the control. The additives BSA and FCS had a significant effect in the maintaining of plasma membrane integrity between 48 and 72 h storage period, compared to the control (P<0.01). The supplementation of BSA and FCS had a protective effect on motility (P<0.05), plasma membrane integrity (P<0.01) and acrosomal integrity (P<0.01) at 72 h compared to the control. The supplementations with BSA and FCS led to a reduction in DNA damage of rabbit sperm at 48 and 72 h during storage period, compared to the control (P<0.001). Although supplementation of BSA and FCS caused significant (P<0.01) decreases in malondialdehyde (MDA) level at 48 h and 72 h, they significantly (P<0.01) increased the glutathione peroxidase (GPx) antioxidant activity up to 72 h when compared to the control group. In conclusion, BSA and FCS supplementation to liquid stored rabbit semen provide a protection for spermatozoa against cool storage-induced DNA damage and plasma membrane integrity by their antioxidative properties.

OXIDATIVE AND ANTIOXIDATIVE EFFECTS OF DESFLURANE AND SEVOFLURANE ON RAT TISSUE IN VIVO

Oxidative and Antioxidative Effects of Desflurane and Sevoflurane on Rat Tissue in Vivo General anaesthetics are often used in patients who are under oxidative stress due to a critical illness or surgical trauma. Some anaesthetics may worsen oxidative stress and some may act as antioxidants. The aim of this study was to evaluate liver, brain, kidney, and lung tissue oxidative stress in rats exposed to desflurane and sevoflurane and in unexposed rats. The animals were divided in three groups: control (received only air); sevoflurane (8 %), and desflurane (4 %). After four hours of exposure, we evaluated the levels of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), Cu, and Zn. Exposure to either of the anaesthetics significantly increased lung MDA levels compared to control (Mann-Whitney U test; P<0.05), probably because it is the tissue directly exposed to anaesthetic gases. Oxidative stress and antioxidant activity in other tissues varied between the desflurane and sevoflurane groups. Our results suggest that anaesthesiologist should not only be aware of the oxidative or antioxidative potential of anaesthetics they use, but should also base their choices on organs which are the most affected by their oxidative action. Utjecaj desflurana i sevoflurana na razine oksidativnog stresa u tkivima štakora Poznato je da kirurške zahvate prati porast razine oksidativnog stresa, kako zbog stvaranja slobodnih kisikovih radikala tako i zbog smanjene aktivnosti obrambenih sustava koji se mogu oduprijeti njihovu djelovanju. Stoga su saznanja o antioksidativnom kapacitetu anestetika koji se primjenjuju prije nekoga kirurškog zahvata vrlo važna i od velikog su kliničkog značenja. Sevofluran i desfluran su inhalacijski anestetici koji se učestalo rabe u svrhu uvođenja bolesnika u anesteziju. Cilj ovog istraživanja bio je utvrditi razine oksidativnog stresa u različitim tkivima štakora i usporediti razlike u odgovoru tkiva na izlaganje navedenim anesteticima. U tu svrhu razine oksidativnog stresa izmjerili smo u jetri, mozgu, bubrezima i plućima štakora podijeljenih u tri eksperimentalne skupine. Kontrolna skupina udisala je samo zrak, dok su druge dvije skupine izložene 8 %-tnomu sevofluranu te 4 %-tnomu desfluranu tijekom 4 h. Nakon završetka obrade životinje su žrtvovane i uzimani su im uzorci tkiva za biokemijske analize. Mjerena je razina malondialdehida (MDA), aktivnost enzima superoksid dismutaze (SOD) i glutation peroksidaze (GSH-Px) te razine bakra i cinka. Izloženost anesteticima izazvala je oksidativni stres u plućima, na što upućuje značajno povišena razina MDA (Mann-Whitney U-test P<0.05) izmjerena u plućnom tkivu štakora obiju izloženih skupina u odnosu na kontrolu. Plućno je tkivo u odnosu na ostala tkiva podložnije štetnim utjecajima reaktivnih kisikovih radikala vjerojatno stoga što je ono prvo izloženo plinovitim anesteticima nakon njihova ulaska u organizam. Razine oksidativnog stresa i antioksidativne aktivnosti koje smo izmjerili u ostalim tkivima bile su različite te su ovisile o primijenjenom anestetiku. Na osnovi dobivenih rezultata možemo zaključiti da bi se zbog različitog odgovora tkiva izbor anestetika trebao provoditi na individualnoj osnovi.

Influence of fetuin and hyaluronan on the post-thaw quality and fertilizing ability of Holstein bull semen ☆

It was determined that fetuin and hyaluronan supplementation did not provide any significant effect on the post-thaw subjective and CASA motility percentages and sperm motion characteristics, in comparison to the controls (P>0.05). Sperm acrosome and total abnormalities were similar in all groups (P>0.05). Groups M (hyaluronan+fetuin) and H (hyaluronan) displayed a higher rate of sperm membrane integrity, compared to that of Group C (control) (P<0.01). According to the results of the comet assay, the lowest percentage of sperm with damaged DNA was achieved in Group H, when compared to all of the experimental groups (P<0.01). Furthermore, all of the additives resulted in a lower rate of sperm with damaged DNA than that of the controls, and thus, reduced DNA damage (P<0.01). For pregnancy rates, there were no significant differences between the extender groups (P>0.05). MDA formation was found to be lower in Groups M and F (P<0.01). In Group M, SOD activity was determined to have significantly increased (23.61±5.62 U/ml) compared to the other groups (P<0.01). All experimental groups had a GSH-Px activity higher than that of the control group (P<0.01).

Oxidative stress enzyme status and frequency of micronuclei in heroin addicts in Turkey.

Abstract Heroin is among the most widely used and dangerous addictive opiate. The World Health Organization (WHO) estimated that more than 15 million people are under the influence of opiate addiction. The aim of this study was to investigate copper zinc-superoxide dismutase (Cu,Zn-SOD), catalase (CAT) and selenium-dependent glutathione peroxidase (Se-GPx) antioxidant enzyme activities, malondialdehyde (MDA) levels and the frequency of micronuclei (MN) in addicts using heroin, the most commonly abused opiate in Turkey. Addicts were defined as individuals diagnosed according to “Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV)” criteria by the “Alcohol and Substance Abuse Treatment and Education Centre-Ankara (AMATEM)”. The control group had no addiction. In comparisons between the groups, a significant decrease in Cu,Zn-SOD activity and increases in MDA levels and MN frequency were observed in addicts. It can be concluded that opiates may cause oxidative stress and that antioxidant supplementation, in addition to pharmacological and psychiatric approaches, can reduce the toxicological effects of these opiates.