Slow freezing versus vitrification for the cryopreservation of zebrafish (Danio rerio) ovarian tissue.

The aim of the present study was to compare the efficiency of vitrification and slow freezing techniques for the cryopreservation of zebrafish ovarian tissue containing immature follicles. In Experiment 1, assessment of cell membrane integrity by trypan blue exclusion staining was used to select the best cryoprotectant solution for each cryopreservation method. Primary growth (PG) oocytes showed the best percentage of membrane integrity (63.5 ± 2.99%) when SF4 solution (2 M methanol + 0.1 M trehalose + 10% egg yolk solution) was employed. The vitrification solution, which presented the highest membrane integrity (V2; 1.5 M methanol + 5.5 M Me2SO + 0.5 M sucrose + 10% egg yolk solution) was selected for Experiment 2. Experiment 2 aimed to compare the vitrification and slow freezing techniques in the following parameters: morphology, oxidative stress, mitochondrial activity, and DNA damage. Frozen ovarian tissue showed higher ROS levels and lower mitochondrial activity than vitrified ovarian tissue. Ultrastructural observations of frozen PG oocytes showed rupture of the plasma membrane, loss of intracellular contents and a large number of damaged mitochondria, while vitrified PG oocytes had intact mitochondria and cell plasma membranes. We conclude that vitrification may be more effective than slow freezing for the cryopreservation of zebrafish ovarian tissue.

The periovulatory endocrine milieu affects the uterine redox environment in beef cows.

BACKGROUND: In cattle, recent studies have shown positive associations between pre-ovulatory concentrations of estradiol (E2), progesterone (P4) at early diestrus and fertility. However, information on cellular and molecular mechanisms through which sex steroids regulate uterine function to support early pregnancy is lacking. Based on endometrial transcriptome data, objective was to compare function of the redox system in the bovine uterus in response to different periovulatory endocrine milieus. METHODS: We employed an animal model to control growth of the pre-ovulatory follicle and subsequent corpus luteum (CL). The large follicle-large CL group (LF-LCL, N=42) presented greater levels of E2 on the day of GnRH treatment (D0; 2.94 vs. 1.27 pg/mL; P=0.0007) and P4 at slaughter on D7 (3.71 vs. 2.62 ng/mL, P=0.01), compared with the small follicle-small CL group (SF-SCL, N=41). Endometrium and uterine washings (N=9, per group) were collected for analyses of variables associated with the uterine redox system. RESULTS: The SF-SCL group had lower endometrial catalase (0.5 vs. 0.79 U/mg protein, P<0.001) and glutathione peroxidase (GPx; 2.0 vs. 2.43 nmol ß-nicotinamide adenine dinucleotide phosphate reduced/min/mg protein, P=0.04) activity, as well as higher lipid peroxidation (28.5 vs. 17.43 nmol malondialdehyde/mg of protein, P<0.001) and superoxide dismutase (SOD) activity (44.77 vs. 37.76 U; P=0.04). There were no differences in the endometrial reactive species (RS) or glutathione (GSH) concentrations between the groups. The uterine washing samples showed no differences in the concentrations of RS or GSH or in total SOD activity (P>0.1). Additionally, catalase, GPx4, SOD1 and SOD2 gene expression was lower in the SF-SCL group than in the LF-LCL group. CONCLUSIONS: We concluded that the intrauterine environment of cows from the LF-LCL group exhibited higher antioxidant activity than that of the cows from the SF-SCL group. We speculate that uterine receptivity and fertility are associated with an optimal redox environment, such as that present in the animals in the LF-LCL group.

γ-Oryzanol protects against acute cadmium-induced oxidative damage in mice testes.

Cadmium is a non-essential heavy metal that is present at low levels mainly in food and water and also in cigar smoke. The present study evaluated the testicular damage caused by acute cadmium exposure and verified the protective role of γ-oryzanol (ORY). Mice were administrated with a single dose of 2.5mg/kg of CdCl2, and then treated with ORY (50mM in canola oil, 5mL/kg). Testes were removed after 24h and tested for lipid peroxidation (TBARS), protein carbonylation, DNA breakage, ascorbic acid, cadmium and non-proteic thiols contents, and for the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST) and δ-aminolevulic acid dehydratase (δ-ALA-D). Cadmium presented a significant alteration in all parameters, except GPx and CAT activities. Therapy reduced in a slight degree cadmium concentration in testes (around 23%). ORY restored SOD and GST activities as well as TBARS production to the control levels. Furthermore, ORY partially recovered δ-ALA-D activity inhibited by cadmium. This study provides the first evidence on the therapeutic properties of ORY in protecting against cadmium-induced testicular toxicity.