The effect of antioxidant supplementation in semen extenders on semen quality and lipid peroxidation of chilled bull spermatozoa

Summary The aim of this study was to determine the effects of the antioxidants superoxide dismutase (SOD), glutathione peroxidase (GPx) and butylated hydroxytoluene (BHT) on microscopic semen parameters and lipid peroxidation following the freeze-thawing of bull semen. Ejaculates were collected from five Holstein bulls and pooled at 37°C. The semen samples were diluted with a CEY extender containing additives including 100 U and 200 U SOD/ml, 50 U or 100 U GPx/ml and an extender containing no antioxidants (control) and stored in liquid nitrogen. The pooled ejaculates were then diluted with CEY or a Tris (hydroxymethyl) aminomethane (TRIS)-based extender (TEY) alone or with added 0.5, 1.0, 2.0 or 4.0 mM BHT, and the routine semen evaluation was conducted. The lowest production of malondialdehyde (MDA) was obtained by addition of 100 U SOD/ml, 0.5 and 1 mM BHT to CEY extender compared with the other groups. Sperm viability and motility was significantly higher when 0.5, 1 mM BHT and 100 U SOD/ml were added in CEY extender. The highest sperm viability was achieved by addition of 50 U GPx/ml to CEY extender. In addition, sperm motility was significantly higher in samples extended in Tris-egg yolk (TEY) with 0.5 mM BHT compared with the control group. The results suggest that CEY extender can be improved with the addition of SOD and BHT

Some biochemical properties of guaiacol peroxidases as modified by salt stress in leaves of salt-tolerant and salt-sensitive safflower (Carthamus tinctorius L.cv.) cultivars

The kinetics properties of guaiacol peroxidase (GP) and its isozymic pattern, and lipid peroxidation product were comparatively analyzed in two varieties of safflower (cv. M-CC-190 as salt-tolerant and cv. IL-111 as salt-sensitive cultivars) under normal and different concentrations of NaCl. The pH profile of GP activity in leaves extract of two cultivars in control and salt stressed plants showed different pattern of pH dependency with three maxima peaks at pH 4.5, 6.5 and 8 in salt-tolerant cultivar and two maxima peaks at pH 4.5 and 6.5 in salt-sensitive cultivar. Comparison of catalytic efficiency for GP between two cultivars at respective pH, showed that, salt-tolerant cultivar in both control and salt stressed conditionhad higher catalytic efficiency than salt-susceptible cultivar. The GP activity on the gels revealed four and two isoforms of peroxidases in salt-tolerant and salt-sensitive cultivars, respectively. GPs increased their expression with higher levels of salinity. However, in salt-sensitive cultivar GPs expression exhibited threshold behavior, with increase expressions in isoenzymes up to a certain level of salinity (25 mM NaCl), followed by decrease to a level of expressions corresponding to the control groups. The levels of lipid peroxidation as indicated by thiobarbituric acid reactive substances (TBARS) were higher in the sensitive variety than the tolerant under control and NaCl salinity. The overall results obtained in this study suggest that, oxidative stress may play an important role in salt-stressedsafflower plants and that the greater protection of M-CC-190 leaves from salt-induced oxidative damage results, at least in part, through the increase of the GPs activity, catalytic efficiency and induction of specific isoenzymes (P1 and P4).Key words: Safflower, guaiacol peroxidase, kinetics, isoenzymes, salt stress

Catalytic properties of three catalases from Kohlrabi (Brassica oleracea gongylodes)

Catalase (EC 1.11.1.6) was extracted from kohlrabi bulbs (Brassica oleracea gongylodes) with 0.05 M phosphate buffer, pH 7.0. On the basis of kinetic studies and activity stain for catalase, only threeisoenzymes of catalases were detected in kohlrabi bulbs extract with pH optima at 4.5, 6.5 and 10. Highest catalytic efficiency (Vmax/Km) value was found for isoenzyme active at pH 6.5. Isoenzyme withpH optima at 4.5 was very sensitive to azide and more resistant to cyanide in comparison to other two isoenzymes active in kohlrabi bulbs extract. Substrate inhibition was found only for the isoenzyme active at pH 4.5. Heat inactivation studies showed a decrease in catalases activity at temperatures above 50, 60 and 70°C for isoenzymes active at pH 6.5, 10 and 4.5, respectively

Antioxidant effects of bovine serum albumin on kinetics, microscopic and oxidative characters of cryopreserved bull spermatozoa

The aim of this study was to determine the effects of bovine serum albumin (BSA) as an antioxidant on post-thaw characters of bull spermatozoa such as motion variables, viability, plasma membrane integrity, morphology, lipid peroxidation, total antioxidant capacity (TAC), total thiols (TT) and the enzymes activities. Ejaculates were collected from six proven bulls and diluted with a citrate-based extender supplemented with various concentrations of BSA (0, 0.5, 1, 1.5 and 2 g/100 mL). The results showed that the semen extender supplemented with various concentrations of BSA increased (p0.05) were detected in progressive motility, sperm track straightness, beat cross frequency, curvilinear velocity and malondialdehyde production between the experimental groups. The highest concentration of BSA (2 g/100 mL) in the semen extender reduced (p<0.05) the sperm motion variables. The results indicated that the most effective concentration of BSA is 1 g/100 mL in the semen extender which is associated with an increase in the total motility, antioxidant enzymes activities, TT and TAC

An overview of advanced biocompatible and biomimetic materials for creation of replacement structures in the musculoskeletal systems: focusing on cartilage tissue engineering

Tissue engineering, as an interdisciplinary approach, is seeking to create tissues with optimal performance for clinical applications. Various factors, including cells, biomaterials, cell or tissue culture conditions and signaling molecules such as growth factors, play a vital role in the engineering of tissues. In vivo microenvironment of cells imposes complex and specific stimuli on the cells, and has a direct effect on cellular behavior, including proliferation, differentiation and extracellular matrix (ECM) assembly. Therefore, to create appropriate tissues, the conditions of the natural environment around the cells should be well imitated. Therefore, researchers are trying to develop biomimetic scaffolds that can produce appropriate cellular responses. To achieve this, we need to know enough about biomimetic materials. Scaffolds made of biomaterials in musculoskeletal tissue engineering should also be multifunctional in order to be able to function better in mechanical properties, cell signaling and cell adhesion. Multiple combinations of different biomaterials are used to improve above-mentioned properties of various biomaterials and to better imitate the natural features of musculoskeletal tissue in the culture medium. These improvements ultimately lead to the creation of replacement structures in the musculoskeletal system, which are closer to natural tissues in terms of appearance and function. The present review article is focused on biocompatible and biomimetic materials, which are used in musculoskeletal tissue engineering, in particular, cartilage tissue engineering