239 POSSIBLE MECHANISMS OF SPERM DAMAGE CAUSED BY HEAT STRESS IN EUROPEAN BULLS RAISED IN TROPICAL ENVIRONMENTS

2011 ◽  
Vol 23 (1) ◽  
pp. 218
Author(s):  
M. Nichi ◽  
R. P. Bertolla ◽  
T. B. Soler ◽  
C. N. M. Cortada ◽  
R. M. Zuge ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Heat Stress ◽  
Structural Damage ◽  
Membrane Integrity ◽  
Rank Test ◽  
Mitochondrial Activity ◽  
Enzymatic Antioxidants ◽  
High Positive Correlation ◽  
Positive Correlation ◽  
Tropical Environments

Previous studies have indicated that semen of heat-stressed bulls shows impaired mitochondrial activity and high levels of oxidative stress, which may cause structural damage to biomolecules, DNA, lipids, carbohydrates and proteins, as well as other cellular components (Nichi et al. 2006 Theriogenology 66, 822–828). Disruption of the sperm mitochondria could have a potential damaging effect not only on an individual sperm cell but also on the surrounding cells, especially regarding the sperm membrane, possibly due to the release of a high amount of reactive oxygen species (ROS) produced in this environment (rich in electrons) that would then lead to oxidative stress. To test this hypothesis, semen samples of 11 Simmental bulls kept in tropical environments were collected during the summer months. Semen was evaluated as follows: the 3-3′ diaminobenzidine stain (DAB) as an index of mitochondrial activity, the hypo-osmotic swelling test (HOST) as an index of membrane integrity, measurement of thiobarbituric acid reactive substances (TBARS) as an index of lipid peroxidation, and measurement of the enzymatic antioxidants superoxide dismutase, catalase and glutathione peroxidase activities. For correlation analysis, the Pearson test was used (variables were transformed when necessary), and for nonparametric variables, the Spearman rank test was used. A high positive correlation was found between sperm cells with highly active mitochondria (DAB class I) and the percentage of cells with intact membrane by HOST (r = 0.93; P < 0.05), and a negative correlation between the latter and the percentage of inactive mitochondria (r = –0.91; P < 0.05), indicating that the higher the percentage of cells showing impaired mitochondrial activity, the higher the percentage of cells with damaged membrane. There was also a positive correlation between TBARS and the percentage of cells with disrupted mitochondria (r = 0.86; P < 0.05), indicating that the higher the percentage of sperm with impaired mitochondrial activity, the higher the oxidative stress. No correlation existed between the enzymatic antioxidants and any of the variables studied. The results indicate that heat stress may lead to an increase in testicular ROS levels, overcoming the seminal antioxidant protection. This, in turn, may cause damage of the mitochondria and a subsequent release of more pro-oxidative substances, and an exponential increase of oxidative stress. Understanding these mechanisms may lead to more tailored antioxidant therapies in the future. The authors thank FAPESP for the scholarship and financial support.

240 FUNCTIONAL TRAITS OF CAT SPERM DURING DISTINCT MATURATION STATUS

2011 ◽  
Vol 23 (1) ◽  
pp. 218
Author(s):  
E. G. A. Perez ◽  
M. Nichi ◽  
C. A. Baptista Sobrinho ◽  
P. A. A. Góes ◽  
A. Dalmazzo ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Lipid Peroxidation ◽  
Structural Damage ◽  
Membrane Integrity ◽  
Domestic Cat ◽  
Lower Percentage ◽  
Mitochondrial Activity ◽  
Computer Assisted ◽  
Suitable Model ◽  
Sperm Analysis

Sperm recovery from the caudae epididymides can be advantageous for preserving semen of endangered animal species. In this context, the domestic cat is a suitable model for the study of sperm physiology in endangered feline species and the research on epididymal sperm preservation combined with the use of reproductive biotechnologies including intracytoplasmic sperm injection (ICSI). The aim of the present study was to examine the sperm collected from the cauda and caput of the cat epididymis using functional tests. Testicles and epididymides from 5 adult tomcats were collected by orchiectomy and maintained at 4°C for 4 h, until semen collection. Semen samples were collected from the epididymal tail and head by careful dissection. Samples were then analysed for motility by computer assisted sperm analysis (CASA; only for the caudal sperm). The 3-3′ diaminobenzidine stain was used as an index of mitochondrial activity, the eosin nigrosin stain as an index of membrane integrity, the simple stain (fast green/Bengal rose) as an index of acrosome integrity, and the measurement of thiobarbituric acid reactive substances (TBARS) as an index of lipid peroxidation. Statistical analysis was performed using the SAS System for Windows (SAS Institute Inc., Cary, NC, USA; least significant differences test and Spearman correlation; P < 0.05). No motility was observed in samples collected from the epididymal head, whereas samples from the tail showed 50.0 ± 4.2% motile spermatozoa. Surprisingly, more spermatozoa with high mitochondrial activity were found in the epididymal head than in samples from the tail (74.0 ± 3.5 v. 50.0 ± 4.3%, respectively). Similarly, samples collected from the head showed a higher susceptibility against the attack of ROS (31.9 ± 5.5 v. 16.3 ± 7.1 ng of TBARS/106 sperm, respectively). Furthermore, epididymal head sperm showed a lower percentage of sperm with intact membrane and a higher percentage of sperm with intact acrosome (44.9 ± 3.3 and 78.4 ± 1.8 v. 66.4 ± 4.2 and 56.7 ± 4.4%, respectively). Our results demonstrate that, during maturation, feline sperm are subjected to high oxidative stress, as shown by the lipid peroxidation assay, which would lead to structural damage to biomolecules, DNA, lipids, carbohydrates and proteins, as well as other cellular components, such as mitochondria, and acrosomal impairment. Similar results were found in humans, in which higher levels of oxidative stress occurred in the post-testicular environment. The plasma membrane seems to be more resistant to damages. This may be due to the described rearrangement in the lipid profile occurring during maturation, but studies to test this hypothesis are still underway.

scholarly journals Melatonin alleviates heat-induced damage of tomato seedlings by balancing redox homeostasis and modulating polyamine and nitric oxide biosynthesis

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Mohammad Shah Jahan ◽  
Sheng Shu ◽  
Yu Wang ◽  
Zheng Chen ◽  
Mingming He ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Nitric Oxide ◽  
Hydrogen Peroxide ◽  
Heat Stress ◽  
Heat Shock ◽  
Defense Mechanism ◽  
Enzymatic Antioxidants ◽  
Tomato Seedlings ◽  
Glutathione Cycle

Abstract Background Melatonin is a pleiotropic signaling molecule that plays multifarious roles in plants stress tolerance. The polyamine (PAs) metabolic pathway has been suggested to eliminate the effects of environmental stresses. However, the underlying mechanism of how melatonin and PAs function together under heat stress largely remains unknown. In this study, we investigated the potential role of melatonin in regulating PAs and nitric oxide (NO) biosynthesis, and counterbalancing oxidative damage induced by heat stress in tomato seedlings. Results Heat stress enhanced the overproduction of reactive oxygen species (ROS) and damaged inherent defense system, thus reduced plant growth. However, pretreatment with 100 μM melatonin (7 days) followed by exposure to heat stress (24 h) effectively reduced the oxidative stress by controlling the overaccumulation of superoxide (O2•−) and hydrogen peroxide (H2O2), lowering the lipid peroxidation content (as inferred based on malondialdehyde content) and less membrane injury index (MII). This was associated with increased the enzymatic and non-enzymatic antioxidants activities by regulating their related gene expression and modulating the ascorbate–glutathione cycle. The presence of melatonin induced respiratory burst oxidase (RBOH), heat shock transcription factors A2 (HsfA2), heat shock protein 90 (HSP90), and delta 1-pyrroline-5-carboxylate synthetase (P5CS) gene expression, which helped detoxify excess ROS via the hydrogen peroxide-mediated signaling pathway. In addition, heat stress boosted the endogenous levels of putrescine, spermidine and spermine, and increased the PAs contents, indicating higher metabolic gene expression. Moreover, melatonin-pretreated seedlings had further increased PAs levels and upregulated transcript abundance, which coincided with suppression of catabolic-related genes expression. Under heat stress, exogenous melatonin increased endogenous NO content along with nitrate reductase- and NO synthase-related activities, and expression of their related genes were also elevated. Conclusions Melatonin pretreatment positively increased the heat tolerance of tomato seedlings by improving their antioxidant defense mechanism, inducing ascorbate–glutathione cycle, and reprogramming the PAs metabolic and NO biosynthesis pathways. These attributes facilitated the scavenging of excess ROS and increased stability of the cellular membrane, which mitigated heat-induced oxidative stress.

scholarly journals Antioxidant Treatment Reduces Formation of Structural Cores and Improves Muscle Function in RYR1Y522S/WTMice

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Antonio Michelucci ◽  
Alessandro De Marco ◽  
Flavia A. Guarnier ◽  
Feliciano Protasi ◽  
Simona Boncompagni
Keyword(s):  
Oxidative Stress ◽  
Skeletal Muscle ◽  
Muscle Function ◽  
Structural Damage ◽  
Mitochondrial Damage ◽  
Mitochondrial Activity ◽  
Release Channel ◽  
Fiber Damage ◽  
Human Mutation

Central core disease (CCD) is a congenital myopathy linked to mutations in the ryanodine receptor type 1 (RYR1), the sarcoplasmic reticulum Ca2+release channel of skeletal muscle. CCD is characterized by formation of amorphouscoreswithin muscle fibers, lacking mitochondrial activity. In skeletal muscle of RYR1Y522S/WTknock-in mice, carrying a human mutation in RYR1 linked to malignant hyperthermia (MH) withcores, oxidative stress is elevated and fibers present severe mitochondrial damage andcores. We treated RYR1Y522S/WTmice with N-acetylcysteine (NAC), an antioxidant providedad libitumin drinking water for either 2 or 6 months. Our results show that 2 months of NAC treatment starting at 2 months of age, when mitochondrial and fiber damage was still minimal, (i) reduce formation ofunstructuredandcontracture cores, (ii) improve muscle function, and (iii) decrease mitochondrial damage. The beneficial effect of NAC treatment is also evident following 6 months of treatment starting at 4 months of age, when structural damage was at an advanced stage. NAC exerts its protective effect likely by lowering oxidative stress, as supported by the reduction of 3-NT and SOD2 levels. This work suggests that NAC administration is beneficial to prevent mitochondrial damage and formation ofcoresand improve muscle function in RYR1Y522S/WTmice.

scholarly journals Metformin Improves Quality of Post-Thaw Canine Semen

Animals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 287 ◽  
Author(s):  
Jérémy Grandhaye ◽  
Agnieszka Partyka ◽  
Zuzanna Ligocka ◽  
Agata Dudek ◽  
Wojciech Niżański ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Sperm Quality ◽  
Membrane Integrity ◽  
Fertilization Rate ◽  
Mitochondrial Activity ◽  
Assisted Reproductive Technique ◽  
Dna Damages ◽  
Semen Extender ◽  
Metabolic Activities

Sperm cryopreservation is an assisted reproductive technique routinely used in canine species for genetic conservation. However, during cryopreservation, the DNA damages are still elevated, limiting the fertilization rate. The present study was conducted to evaluate whether supplementation of canine semen extender with a molecule limiting the metabolic activities can improve the quality of frozen-thawed canine spermatozoa. We used metformin, known to limit the mitochondrial respiratory and limit the oxidative stress. Before and during the freezing procedure, metformin (50µM and 500µM) has been added to the extender. After thawing, sperm exposed to metformin conserved the same viability without alteration in the membrane integrity or acrosome reaction. Interestingly, 50µM metformin improved the sperm motility in comparison to the control, subsequently increasing mitochondrial activity and NAD+ content. In addition, the oxidative stress level was reduced in sperm treated with metformin improving the sperm quality as measured by a different molecular marker. In conclusion, we have shown that metformin is able to improve the quality of frozen-thawed dog semen when it is used during the cryopreservative procedure.

scholarly journals Resveratrol Improves Boar Sperm Quality via 5′AMP-Activated Protein Kinase Activation during Cryopreservation

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Zhendong Zhu ◽  
Rongnan Li ◽  
Xiaoteng Fan ◽  
Yinghua Lv ◽  
Yi Zheng ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Sperm Quality ◽  
Membrane Integrity ◽  
Mitochondrial Activity ◽  
Enzymatic Antioxidants ◽  
Ros Production ◽  
Compound C ◽  
Ampk Phosphorylation ◽  
Boar Sperm ◽  
Amp Activated Protein Kinase

Mammalian sperm is highly susceptible to the reactive oxygen species (ROS) stress caused by biochemical and physical modifications during the cryopreservation process. 5′AMP-activated protein kinase (AMPK) is involved in regulating both cell metabolism and cellular redox status. The aim of the present study was to investigate whether the resveratrol protects boar sperm against ROS stress via activation of AMPK during cryopreservation. Boar sperm was diluted with the freezing medium supplemented with resveratrol at different concentrations (0, 25, 50, 75, 100, and 125 μM). It was observed that the addition of 50 μM resveratrol significantly improved the postthaw sperm progressive motility, membrane integrity, acrosome integrity, mitochondrial activity, glutathione (GSH) level, activities of enzymatic antioxidants (glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase), and the phosphorylation of AMPK. Meanwhile, the lipid peroxidation, ROS levels, and apoptosis of postthaw sperm were reduced in the presence of 50 μM resveratrol. Furthermore, when fresh boar sperm was incubated with the medium in the presence of 50 μM resveratrol and 30 μM Compound C (an AMPK inhibitor), the effects of the resveratrol were partly counteracted by the Compound C. These observations suggest that the resveratrol protects boar sperm via promoting AMPK phosphorylation. In conclusion, the addition of resveratrol to the freezing extenders protects boar sperm against ROS damage via promoting AMPK phosphorylation for decreasing the ROS production and improving the antioxidative defense system of postthaw sperm. These findings provide novel insights into understanding the mechanisms of resveratrol on how to protect boar sperm quality contrary to the ROS production during cryopreservation.

scholarly journals Analyzing effect of altitudinal variation in Enzymatic antioxidants of Coleus forskohlii from Uttarakhand, India

2019 ◽  
Author(s):  
Pawan Singh Rana ◽  
Pooja Saklani
Keyword(s):  
Oxidative Stress ◽  
Antioxidant Potential ◽  
Strong Positive Correlation ◽  
Enzymatic Antioxidants ◽  
Coleus Forskohlii ◽  
Altitudinal Variation ◽  
Lower Altitude ◽  
Positive Correlation ◽  
Enzymatic Antioxidant ◽  
High Oxidative Stress

AbstractEnzymatic antioxidant activity of the five populations of the medicinal plant Coleus forskohlii from five locations of varied altitudes was assayed to analyze the effect of altitude on the enzymatic antioxidant potential. The various enzymes assayed were SOD, CAT, POD, PPO, APX and GR. Highest activity for all the enzymes was observed at higher altitudes. Strong positive correlation was observed between the protein content, enzyme activities and altitude. CAT, POD and GR activity increases significantly with the altitude while SOD was least affected. APX and PPO shows positive correlation. High activity of all these enzymes seems to be to combat the high oxidative stress at higher altitudes. Results of the present study suggest that Coleus forskohlii population growing at a higher altitude has higher antioxidant potential than those at lower altitude. Thus, the population of Coleus forskohlii from a higher altitude can be used as a source of antioxidants and for commercial propagation.

242 PROTECTIVE EFFECT OF VITAMIN E TREATMENT IN HEAT-STRESSED BOS TAURUS BULLS

2013 ◽  
Vol 25 (1) ◽  
pp. 269 ◽  
Author(s):  
V. H. Barnabe ◽  
R. C. Barnabe ◽  
P. Goes ◽  
E. G. A. Perez ◽  
J. D. A. Losano ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Heat Stress ◽  
Vitamin E ◽  
Bos Taurus ◽  
Semen Quality ◽  
Reactive Oxygen ◽  
Mitochondrial Activity ◽  
Oxygen Species ◽  
Tropical Conditions

Bos taurus bulls, when raised under tropical conditions, are highly susceptible to heat stress, which leads to impaired semen quality, leading to significant economical losses because, in these regions, the reproductive mounting season occurs mainly during the summer. Previous studies have indicated that oxidative stress (i.e. attack by reactive oxygen species) may be the main mechanism of sperm damage in such conditions. Therefore, treatment with antioxidants may be an important alternative to improve semen quality in heat-stressed B. taurus bulls. The objective of the present study was to evaluate whether the treatment with vitamin E, an important antioxidant, could improve sperm quality in insulated bulls. Towards this aim, eight adult Holstein bulls were submitted for semen collection, and the sperm was submitted for motility evaluation by computer-assisted sperm analysis (Ivos, Hamilton Thorne Inc., Beverly, MA, USA), examination of membrane and acrosomal integrity (eosin/nigrosin and fast green/bengal rose stain, respectively), mitochondrial activity (diaminobenzidine stain; full mitochondrial activity or no mitochondrial activity), and sperm susceptibility to oxidative stress (thiobarbituric acid-reactive substances). Bulls were then insulated (testicles covered in a thermal bag for 3 days) and randomly assigned to two treatment groups: no vitamin E (placebo) and vitamin E (subcutaneous injection of 3000 IU of α-tocopherol each of 10 days). Subsequent semen analysis was performed 1 and 60 days after the insulation. Statistical analysis was performed with SAS (SAS Institute Inc., Cary, NC, USA) repeated-measures ANOVA, and significance of P < 0.05 was adopted. No differences were found on any of the variables before insulation. One day after insulation, animals treated with vitamin E showed a lower percentage of static sperm and a higher percentage of motile sperm when compared with animals treated with the placebo (28 and 63% v. 56 and 34%, respectively; P < 0.05). Also at this time, sperm susceptibility to oxidative stress was lower in animals treated with vitamin E (vitamin E: 410 ng/106 sperm; no vitamin E: 1760 ng/106 sperm; P < 0.05). Sixty days after insulation, sperm susceptibility to oxidative stress was still lower in animals treated with vitamin E when compared with the placebo group (1176 and 192 ng/106 sperm, respectively; P < 0.05). However, no differences were found on the other variables. Results indicate that vitamin E, an antioxidant whose main function is protection of the plasma membrane, may be an alternative to avoid the acute deleterious effects of the heat stress in B. taurus bulls raised under tropical conditions. In addition, even with no heat stress involved, vitamin E treatment may provide constant protection, increasing the resistance of the sperm against the reactive oxygen species.

scholarly journals Correlations of circulating levels of oxidants, antioxidants and soluble Fas in breast cancer among Egyptian females

2016 ◽  
Vol 5 (2) ◽  
pp. 110
Author(s):  
Sayed Hamada Madboly ◽  
Elsaeid Mostafa Elsaeid Elbawab ◽  
Abdallah M. A.A. El-Ebidi ◽  
Omar Abd-El raheem Sayed ◽  
Mohammed H. Hassan ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Oxidative Stress ◽  
Colorimetric Assay ◽  
University Hospital ◽  
Soluble Form ◽  
Control Group ◽  
P Value ◽  
High Positive Correlation ◽  
Positive Correlation ◽  
Malignant Group

<p><strong>Background:</strong> Breast cancer is the first most common malignancy in Egyptian females. Oxidative stress is considered to be involved in the pathophysiology of all cancers, especially breast cancer<strong>. </strong>An inappropriately low rate of apoptosis can give rise to cancer.<strong></strong></p><p><strong>Objectives:</strong> The purpose of this study was to asses, compare and correlate the circulatory levels of some oxidants (malondialdehyde "MDA" and nitric oxide "NO"), total antioxidant capacity "TAO") and soluble form of Fas "sFas" in some Egyptian females having breast cancer.<strong></strong></p><p><strong>Methods: </strong>A cross sectional case/control study conducted on 50 Egyptian females recruited from outpatient clinics or inpatients department of the general surgery at Sohag university hospital, divided into 30 females with malignant breast lesion and 20 healthy females as a control group. Colorimetric assay of serum levels of NO, MDA and TAO, while, sFas was determined using ELISA method.</p><p><strong>Results:</strong> There were significant high levels of NO, MDA, TAO and sFas in malignant group than in control group with p-value &lt; 0.0001, high positive correlation between NO, MDA, TAO and sFas in malignant group ( r= 0.958, 0.807, 0.748 respectively and P&lt; 0.0001 for all<strong>). </strong>There was high positive correlation between NO and TAO in malignant group (r = 0.78, P &lt; 0.0001).There was also<strong>, </strong>high positive correlation between MDA and TAO in malignant group (r = 0.81, P &lt; 0.0001).<strong></strong></p><p><strong>Conclusion: </strong>These results support the oxidative stress hypothesis and resistance to apoptosis in development and progression of breast cancer.</p>

93 EFFECT OF ANTIOXIDANTS SUPPLEMENTATION ON THE QUALITY OF CRYOPRESERVED SPERM OF DOGS

2011 ◽  
Vol 23 (1) ◽  
pp. 152
Author(s):  
C. A. B. Sobrinho ◽  
M. Nichi ◽  
P. A. A. Góes ◽  
A. Dalmazzo ◽  
S. E. Crusco ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Vitamin E ◽  
Reactive Oxygen ◽  
The Other ◽  
Mitochondrial Activity ◽  
Enzymatic Antioxidants ◽  
Oxygen Species ◽  
Intact Membrane

One of the main causes of poor quality of frozen–thawed dog sperm is oxidative stress (i.e. higher production of reactive oxygen species not compensated by improved antioxidant protection). This event is known to impair sperm functionality by attacking plasma membrane, acrosome, mitochondria, and DNA. Spermatozoa are particularly susceptible the oxidative stress, mainly due to the reduced cytoplasm and the high content of polyunsaturated fatty acids (PUFA) in the membrane, which allows the spermatozoa to be motile and confers a higher resistance against the damages caused by cryopreservation, but makes the sperm more susceptible to the attack of the reactive oxygen species (ROS). The present study aimed to evaluate the effects of antioxidant supplementation on semen extender (Tris-egg yolk-citrate-glicerol) with glutathione (GSH) and vitamin E on the quality of cryopreserved dog sperm. Ejaculates of 12 dogs were divided in pools of 3 ejaculates with at least 70% of motility. Each pool was diluted with 7 different extenders for treatment groups as follows: control, vitamin E (1, 5, and 10 mM), and reduced glutathione (GSH; 1, 5, and 10 mM) and submitted to cryopreservation. Samples were thawed (37°C/30′) and evaluated for motility, vigor, percentage of sperm showing intact membrane (eosin/nigrosin), and acrosome (simple stain fast-green and bengal rose), mitochondrial activity (3–3′-diaminobenzidine-DAB), and sperm susceptibility to oxidative stress (TBARS). Statistical analyses were performed using the SAS system for Windows (SAS Institute Inc., Cary, NC, USA; least significant differences test and Spearman correlation; P < 0.05). Samples treated with 1 mM of GSH showed a higher percentage of sperm with intact membrane when compared with the control (11.21 ± 2.84 and 6.21 ± 1.16%, respectively; P < 0.05). On the other hand, treatment with 5 mM of GSH showed better results regarding mitochondrial activity. Vitamin E supplementation also played a protective role on mitochondrial activity; samples treated with 1 mM showed a lower percentage of DAB III sperm (cells with severely compromised mitochondrial activity) when compared with the control group (5.61 ± 0.7 and 8.62 ± 1.05%, respectively; P < 0.05). Both vitamin E and GSH are important non-enzymatic antioxidants responsible for the destruction of the hydroxyl radical. Despite the positive influence of these antioxidants on mitochondrial status, no effect was found on the other variables studied. These results indicate that the action of both antioxidants in dog sperm would be mainly intracellular. Furthermore, other ROS could be responsible for the other damages caused by cryopreservation on the other sperm functionalities (i.e. membrane, acrosome, DNA, oxidative status). Therefore, the use of a combination of enzymatic and non-enzymatic antioxidants could be an alternative to overcome the deleterious influence of oxidative stress in cryopreserved semen of dogs. The authors thank the Brazilian army for the dogs used in this study.

91 TREATMENT OF GOAT SPERM WITH CATALASE TO IMPROVE POST-THAW QUALITY

2011 ◽  
Vol 23 (1) ◽  
pp. 151
Author(s):  
R. O. C. Silva ◽  
M. Nichi ◽  
E. G. A. Perez ◽  
P. A. A. Góes ◽  
A. Dalmazzo ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Structural Damage ◽  
Sperm Quality ◽  
Membrane Integrity ◽  
Thiobarbituric Acid ◽  
Lower Percentage ◽  
Sperm Chromatin ◽  
Mitochondrial Activity ◽  
Computer Assisted ◽  
Sperm Analysis

Semen cryopreservation is extremely important to the use of reproductive biotechnologies in goats. However, studies indicate that cryopreservation may lead to increased oxidative stress which may cause structural damage to biomolecules, DNA, lipids, carbohydrates, and proteins, as well as other cellular components. Previous studies performed by our group indicate fresh goat sperm is highly susceptible to the attack of hydrogen peroxide. Therefore, the treatment with hydrogen peroxide scavengers would be an alternative to improve post-thaw sperm quality in goats. The aim of the present study was to evaluate the efficiency of catalase, an important hydrogen peroxide scavenger, to improve post-thaw quality in cryopreserved goat semen samples. Semen samples from 5 adult goats were collected and cryopreserved (Botu-Bov®, Biotech Ltda.). After thawing, samples were incubated (2 h, 37°C) with 0, 60, 120, and 240 UI mL–1 of catalase. Samples were then analysed for motility using the computer assisted sperm analysis (CASA); the 3–3′ diaminobenzidine stain, as an index of mitochondrial activity; the eosin nigrosin stain, as an index of membrane integrity; the simple stain (Fast green/Bengal rose), as an index of acrosome integrity; sperm chromatin structure assay, as an index of DNA fragmentation; and the measurement of thiobarbituric acid reactive substances (TBARS), as an index of lipid peroxidation. Statistical analysis was performed using the SAS System for Windows (SAS Institute Inc., Cary, NC, USA; least significant differences test and Spearman correlation; P < 0.05). Results showed that catalase treatment after thawing played a role on improving mitochondrial activity. Samples treated with 240 UI mL–1 showed lower percentage of sperm showing low mitochondrial activity when compared with samples treated with 0 and 120 UI mL–1 of catalase (6.5 ± 2.3, 17.2 ± 3.5, and 10.0 ± 1.3%, respectively). However, no effect of catalase was observed on any of the other variables studied. Results indicate that catalase, despite its beneficial effect on mitochondrial activity, does not influence positively on sperm quality after thawing. A hypothesis to explain such results would be that because of seminal plasma dilution with the extender, the antioxidants were also diluted. Therefore, the antioxidant protection would be impaired and the most deleterious reactive oxygen species, as observed in fresh semen, would also be different depending on the semen extender used because sperm are extremely dependent on the extracellular environment due to the reduced cytoplasm and the high content of polyunsaturated fatty acids in the membrane. A study performed by our group confirms such a hypothesis. Possibly, the treatment with catalase would be more effective if performed before cryopreservation. Also, it is possible that the use of different antioxidants would provide better results. Thanks to Nutricell for the media used and CAPES for financial support.

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