Full confluency, serum starvation, and roscovitine for inducing arrest in the G0/G1 phase of the cell cycle in puma skin-derived fibroblast lines

The puma population is constantly decreasing, and cloning by somatic cell nuclear transfer can be used to conserve the species. One of the factors determining the success of the development of cloned embryos is the cell cycle stage of the donor cells. We evaluated the effects of full confluency (~100%), serum starvation (0.5% serum), and roscovitine (15 µM) treatments on the cell cycle synchronization in G0/G1 of puma skin-derived fibroblasts by flow cytometric analysis. Also, we assessed the effects of these synchronization methods on morphology, viability, and apoptosis levels using microscopy tools. The results showed that culturing the cells to confluence for 24 h (84.0%), 48 h (84.6%), and 72 h (84.2%) and serum starvation for 96 h (85.4%) yielded a significantly higher percentage of cells arrested in the G0/G1 (P < 0.05) phase than cells not subjected to any cell cycle synchronization method (73.9%). Nevertheless, while serum starvation reduced the percentage of viable cells, no difference was observed for the full confluence and roscovitine treatments (P > 0.05). Moreover, roscovitine for 12 h (78.6%) and 24 h (82.1%) was unable to synchronize cells in G0/G1 (P > 0.05). In summary, full confluency induces puma fibroblast cell cycle synchronization at the G0/G1 stage without affecting cell viability. These outcomes may be valuable for planning donor cells for somatic cell nuclear transfer in pumas.(AU)

Heterologous in vitro fertilization and embryo production for assessment of jaguar (Panthera onca Linnaeus, 1758) frozen-thawed semen in different extenders

Heterologous in vitro fertilization (IVF) is an important tool for assessing fertility of endangered mammals such as the jaguar, considering difficult access to females for artificial insemination and to obtain homologous oocytes. We aimed to evaluate the fertility of jaguar sperm cryopreserved with different extenders, using domestic cat oocytes to assess the development of hybrid embryos. Semen from four captive jaguars was obtained by electroejaculation. Samples were cryopreserved in powdered coconut water (ACP-117c) or Tris extender containing 20% egg yolk and 6% glycerol. Thawed spermatozoa were resuspended (2.0 × 106 spermatozoa/mL) in IVF medium and co-incubated with cat oocytes matured in vitro for 18 h. Presumptive zygotes were cultured for 7 days. After 48 h, cleavage rate was evaluated, and non-cleaved structures were stained for IVF evaluation. On days 5 and 7, the rate of morula and blastocyst formation was assessed. Data were analyzed using the Fisher exact test (p < 0.05). No difference was observed between ACP-117c and Tris extenders, respectively, for oocytes with 2nd polar body (2/51, 3.9 ± 2.9% vs. 2/56, 3.6 ± 3.1%), pronuclear structures (5/51, 9.8 ± 4.7% vs. 8/56, 14.3 ± 8.0%), and total IVF rates (7/36, 19.4 ± 5.0% vs. 10/37, 27.0 ± 13.8%). All the samples fertilized the oocytes, with 22.9 ± 3.2% (16/70) and 16.7 ± 3.6% (12/72) cleavage of mature oocytes for ACP-117c and Tris extenders, respectively. Morula rates of 4.3 ± 2.3% (3/70) and 5.6 ± 2.2% (4/72) were observed for ACP-117c and Tris, respectively. Only the Tris extender demonstrated blastocyst production (2/12, 16.7 ± 1.5% blastocyst/cleavage). We demonstrated that jaguar ejaculates cryopreserved using ACP-117c and Tris were suitable for IVF techniques, with blastocyst production by ejaculates cryopreserved in Tris. This is a first report of embryos produced in vitro using jaguar sperm and domestic cat oocytes through IVF.(AU)

Produção de embriões partenogenéticos de cutias usando Cloreto de Estrôncio e Citocalasina B / Production of parthenogenetic embryos from agoutis using strontium chloride and cytochalasin B

The study aimed to evaluate the effect of strontium chloride (SrCl2) with cytochalasin B (CB) on the activation of agouti oocytes matured in vitro for embryo production. Thus, ovaries were used for oocyte recovery by slicing. Subsequently, viable oocytes were destined for in vitro maturation (IVM) and after 24 h evaluated for the expansion and viability of the cumulus cells and presence of the first polar body (1PB). After IVM, oocytes were activated with a combination of 10 mM SrCl2 and 5 μg/mL CB for 6 h and evaluated for embryo development kinetics. Hence, 93.3% of cumulus cell expansion was observed, with 91.2% viability and 37.3% of oocytes with the presence of 1PB. Regarding embryonic development, 43.2% (19/44) of cleaved structures and 6.8% (3/44) of morulae were observed in relation to the number of oocytes and 18.8% (3/16) morulae in relation to the number of cleaved structures. Thus, the combination of SrCl2 with CB promoted the activation of oocytes matured in vitro from agouti resulting in morulae. Finally, with this study, fundamental steps for in vitro conservation through reproductive biotechniques were developed in agoutis.

Efeitos da suplementação do meio com diferentes antioxidantes durante a maturação in vitro de oócitos de bovinos sobre o status oxidativo / Effects of medium supplementation with different antioxidants during in vitro maturation of bovine oocytes on oxidative status

Although widely used as reproductive biotechnology in cattle, in vitro embryo production (IVEP) has variable efficiency. During in vitro maturation (IVM), supplementing the medium with antioxidant potential could be an affordable alternative to increase the efficiency of IVEP, requiring the evaluation of new components, such as eugenol, β-caryophyllene, and acetyl eugenol. Thus, bovine oocytes were matured according to different antioxidants. Metaphase II oocytes were identified by Hoechst staining. The oxidative status was measured by evaluation of reactive oxygen species (ROS), and glutathione (GSH). After eight repetitions, no difference was observed among groups containing antioxidants, being all these groups superior to negative control (p<0.05). The ROS levels decreased and GSH increased in oocytes matured with EUG (p<0.05). These results indicate apositive effect of eugenol on the oxidative status of oocytes matured with this compound, showing that eugenol can be an efficient supplement in the IVM of bovine oocytes.

Efeitos da suplementação do meio com diferentes antioxidantes durante a maturação in vitro de oócitos de bovinos sobre o status oxidativo / Effects of medium supplementation with different antioxidants during in vitro maturation of bovine oocytes on oxidative status

Although widely used as reproductive biotechnology in cattle, in vitro embryo production (IVEP) has variable efficiency. During in vitro maturation (IVM), supplementing the medium with antioxidant potential could be an affordable alternative to increase the efficiency of IVEP, requiring the evaluation of new components, such as eugenol, β-caryophyllene, and acetyl eugenol. Thus, bovine oocytes were matured according to different antioxidants. Metaphase II oocytes were identified by Hoechst staining. The oxidative status was measured by evaluation of reactive oxygen species (ROS), and glutathione (GSH). After eight repetitions, no difference was observed among groups containing antioxidants, being all these groups superior to negative control (p<0.05). The ROS levels decreased and GSH increased in oocytes matured with EUG (p<0.05). These results indicate apositive effect of eugenol on the oxidative status of oocytes matured with this compound, showing that eugenol can be an efficient supplement in the IVM of bovine oocytes.(AU)

Produção de embriões partenogenéticos de cutias usando Cloreto de Estrôncio e Citocalasina B / Production of parthenogenetic embryos from agoutis using strontium chloride and cytochalasin B

The study aimed to evaluate the effect of strontium chloride (SrCl2) with cytochalasin B (CB) on the activation of agouti oocytes matured in vitro for embryo production. Thus, ovaries were used for oocyte recovery by slicing. Subsequently, viable oocytes were destined for in vitro maturation (IVM) and after 24 h evaluated for the expansion and viability of the cumulus cells and presence of the first polar body (1PB). After IVM, oocytes were activated with a combination of 10 mM SrCl2 and 5 μg/mL CB for 6 h and evaluated for embryo development kinetics. Hence, 93.3% of cumulus cell expansion was observed, with 91.2% viability and 37.3% of oocytes with the presence of 1PB. Regarding embryonic development, 43.2% (19/44) of cleaved structures and 6.8% (3/44) of morulae were observed in relation to the number of oocytes and 18.8% (3/16) morulae in relation to the number of cleaved structures. Thus, the combination of SrCl2 with CB promoted the activation of oocytes matured in vitro from agouti resulting in morulae. Finally, with this study, fundamental steps for in vitro conservation through reproductive biotechniques were developed in agoutis.(AU)