No abstract

The IGF system is related to embryo quality. We aim to determine the effect of the heat stress on the mRNA expression of IGF1 and IGF2, IGFR1 and IGFR2, IGFBP2 and IGFBP4, and PAPPA in in vitro production (IVP) blastocysts from Nelore and Holstein after ovum pick up (OPU) to better understand the differences between these breeds. Oocytes from four Nelore and seven Holstein were collected in six OPU sessions. Following in vitro maturation and fertilization using six Nelore or Holstein sires, embryos were divided into control (cultured at 39°C) and heat stress (HS; exposed to 41°C for 9 h). Blastocysts were submitted to RNA extraction. The IGF1 expression was higher in blastocysts under HS in both breeds, and the expression of IGFBP2 and IGFBP4 was higher in Holstein blastocysts under HS. The high PAPPA expression and the low expression of IGFBP2 and IGFBP4 are associated with a more efficient degradation of IGFBPs, which results in greater IGF bioavailability in Nelore blastocysts and may contribute to the superior HS tolerance in Nelore, when compared to Holstein.

The aim of this experiment was to evaluate the effects of cycloxigenase inhibitor drugs, i.e. flunixin meglumine (FM) and parecoxib (P), on the development of bovine embryos cultured in vitro until the blastocyst and hatched blastocyst stages. Immature oocytes were aspirated from slaughterhouse ovaries and morphologically selected for IVM (Monteiro FM et al. 2007 Anim. Reprod. 4, 51–58). Twenty hours after maturation (39°C and 5% CO2 in air), matured oocytes were transferred to fertilization media, inseminated with frozen–thawed semen, and incubated for 10 to 12 h. Presumptive zygotes (PZ) were then transferred to TCM 199 HEPES medium, vortexed to remove cumulus cells and finally to drops of IVC media (SOFaaci plus 5% BFS [Gibco] with 13 mm sodium pyruvate). Each drop of IVC medium had appropriate concentrations of FM (0.14/n = 123; 1.4/n = 122; 14/n = 117; 140/n = 44 or 1400 μg mL–1/n = 44 PZ) or P (0.09/n = 134; 0.9/n = 109; 9/n = 118; 90/n = 113 or 900 μg mL–1/n = 45 PZ), besides extra drops as control groups (CFM; n = 124 and CP; n = 149 PZ). Based on published data from bovine (FM) and human (P) administered concentrations, it was calculated the blood concentration to a bovine weighing 450 kg (FM = 14 and P = 9 μg mL–1). Both drugs were used from available commercial preparations, and in a pilot test, there were no deleterious effects of the solvent itself on the blastocyst and hatched blastocyst rates. During culture, petri dishes containing PZ/embryos were kept into plastic bags, under controlled atmosphere of 5% O2, 5% CO2 and 90% N2 at 39°C. There were 11 replicates for each treatment. In all drops (both drug concentrations and control group) the blastocyst and hatched blastocyst rates (BR and HBR, respectively) were evaluated at 144 and 192 h after fertilization, respectively. Statistical analysis was performed with ANOVA on ranks (Dunn’s test a posteriori and significance being considered when P < 0.05; BioEstat version 5.0). According to the results, FM (1400 and 140 μg mL–1) and P (900 μg mL–1) concentrations were toxic enough for a complete inhibition of in vitro bovine embryo development. There were no significant differences among the other drug concentrations and their respective control group, on the BR (27.7 ± 3.9; 29.6 ± 3.4 and 29.8% ± 4.8) and HBR (13.5 ± 4.4; 15.6 ± 3.8 and 22.1% ± 5.1), respectively to 0.14; 1.4 and 14 μg mL–1 for FM; on BR (26.0 ± 2.6; 18.2 ± 4.6; 25.8 ± 5.9 and 23.2% ± 4.8) and HBR (14.1 ± 3.3; 10.2 ± 3.3; 16.8 ± 3.8 and 12.0% ± 3.4), respectively to 0.09; 0.9; 9 and 90 μg mL–1 for P; and on BR (35.3 ± 5.2 and 36.5% ± 3.4) and HBR (26.6 ± 4.5 and 19.8% ± 3.6), respectively for CFM and CP. The results suggest that, during in vitro bovine embryo culture, there was no significant toxicity of either drug, with exception of the complete lethal concentrations of 140 and 1400 μg mL–1 (flunixin meglumine) and 900 μg mL–1 (parecoxib) on blastocyst production. Supported by FAPESP – Brazil (MFGN 06/06491-2 and 07/07705-9; EMR 07/04284-2; RAS; CFS and RALS) and CAPES – Brazil.

There is evidence that deleterious effects of heat shock (HS) on fertility are less pronounced in breeds tolerant to high temperatures, due mainly to differences in their thermoregulatory capacity. In vitro experiments have shown that Bos indicus embryos are more resistant to HS than Bos taurus. In order to better understand the differences related to HS resistance between Bos indicus and Bos taurus, the main objective of this study was to determine if tolerance to HS is caused by genetic contribution from the oocyte, spermatozoa, or both. Additionally, the influence of the time between collection of ovaries in the abattoir and oocyte aspiration in the laboratory on early embryo development was ascertained. In experiment 1, oocytes from Nellore and crossbreed Holstein cows (cHOL) were collected in a local abattoir, matured and fertilized using semen (n = 6 for each breed) from Nellore (NEL), Angus (ANG), Brahman (BRA,) and Gir (GIR) bulls. In experiment 2, oocytes from Nellore and Holstein (HOL) cows were collected in an abattoir and the oocytes were aspirated in the laboratory 4 (group 4 h) or 6.5 h (group 6.5 h) later, matured and fertilized using semen (n = 6 for each breed) from NEL, GIR, and HOL. In both experiments, 96 h post-insemination (hpi), embryos with > 16 cells were separated in 2 groups: control and HS. In the control group the embryos were cultured at 39°C, whereas in the HS group the embryos were submitted to 41°C for 12 h, and then returned to 39°C. In experiments 1 and 2 the results were analyzed by ANOVA (Proc MIXED, SAS Institute, Cary, NC, USA). In experiment 1, there was no effect of HS on blastocyst and hatched blastocyst rates in all breeds studied. The percentage of oocytes that cleaved and reached the morula stage was significantly lower (P < 0.05) in cHOL × GIR compared with the other breeds. Additionally, blastocyst rate was higher in cHOL × NEL than in cHOL × ANG and cHOL × GIR (P < 0.05). In experiment 2, cleavage, morula, and blastocyst rates in group 4 h were higher (P < 0.05) compared with group 6.5 h. The HS decreased blastocyst rates in all breeds (NEL × NEL, HOL × HOL, and HOL × GIR), and in both time intervals (4 and 6.5 h). The breed NEL × NEL had higher cleavage rate (P < 0.05) for both time intervals compared with HOL × HOL and HOL × GIR. In addition, Nellore oocytes fertilized with Nellore semen (NEL × NEL) originated higher blastocyst rates (P < 0.05) in control and HS group than the other breeds. We conclude that (a) embryos from Holstein are more susceptible to HS than embryos from crossbred Holstein; (b) the oocyte is more important than the spermatozoa for the development of thermotolerance, because the breed of the bull did not influence embryo development after HS; (c) in vitro early embryonic development was impaired by increasing (from 4 to 6.5 h) the time interval between ovary collection and oocyte aspiration. Fellowships to T. Nabhan from CAPES and to R. A. Satrapa, R. A. L. Simoes, and E. M. Razza from FAPESP. Funding from FAPESP (Sao Paulo, Brazil).

Importância do problema: A síndrome da deficiência do transportador de glicose tipo 1 (GLUT1DS), descrita pela primeira vez por De Vivo em 1991, é causada por um deficitário transporte de glicose na barreira hematoencefálica e astrócitos por mutações na maioria das vezes de novo heterozigóticas no gene SLC2A1, responsável pela codificação do transportador de glicose tipo 1 (GLUT-1). Esta mutação limita a disponibilidade de glicose cerebral levando a sua deficiência energética, sendo o mecanismo gerador de suas manifestações clínicas. Os sintomas sugestivos são convulsões, atraso no desenvolvimento, microcefalia, hipotonia, espasticidade e complexas alterações no movimento consistindo de ataxia e distonia. Em pacientes GLUT1DS, substratos energéticos alternativos são de fundamental importância. Inúmeros trabalhos recomendam a utilização da dieta cetogênica de maneira imperiosa como mecanismo padrão ouro de tratamento. Esta, nos primeiros anos de vida em pacientes com GLUT1DS, garante um melhor resultado cognitivo e melhora nos aspectos psicomotores. Comentários: A GLUT1DS por ser uma doença de recente descoberta, poucos casos descritos na literatura, características clínicas heterogêneas e falta substancial de casuística é muitas vezes subdiagnosticada. Neste sentido, critérios de suspeição e algoritmos diagnósticos se fazem necessários. Desta maneira, o objetivo deste artigo é chamar a atenção da comunidade médica brasileira a essa síndrome com vistas a incrementar seu diagnóstico e melhorar o prognóstico de epilepsias de difícil controle.

There is evidence that IGF system can be involved in the oocyte competence and, consequently, in the embryo development. To better understand possible differences between Bos taurus and Bos indicus in in vitro embryo development, the current work aimed to assess the expression of IGF ligands (IGF-1 and 2), types 1 and 2 IGF receptors (IGFR1 and 2), IGF-binding proteins 2 and 4 (IGFBP-2 and 4), and type A pregnancy-associated plasmatic protein (PAPP-A) mRNA in bovine immature oocytes fromBos Taurus and Bos indicus. Nellore and Holstein cows were submitted to ovum pickup, and the oocytes with grade 1, 2, and 3 were selected. To remove cumulus cells and pellucida zone, respectively, the oocytes were submitted to vortex (900 × g for 3 min) and protease treatment (Protease® from Streptomyces griseus, Sigma-Aldrich Corporation, St. Louis, MO, USA). Pools of 20 oocytes obtained from Nellore (n = 8) and Holstein (n = 4) cows were submitted to total RNA extraction (RNeasy, Qiagen, Valencia, CA, USA). The gene expression of target genes was measured by real-time RT-PCR with oligo-dT in the RT and bovine-specific primers in the PCR. Expression of cyclophlin A (CYC-A) was used as internal control. The means of mRNA levels of target genes between the breeds were compared using t-test and Mann-Whitney test when the data had normal or not normal distribution, respectively. The means values of mRNA expression of IGF-1, IGF-2, IGF receptors (1 and 2), and IGFBP 2 and 4 were greater in Holstein (0.96 ± 0.21, 0.74 ± 0.27, 1.08 ± 0.04, 1.19 ± 0.5, 1.21 ± 0.23, 0.53 ± 0.15, respectively) compared with Nellore (0.48 ± 0.10, 0.07 ± 0.02, 0.04 ± 0.03, 0.06 ± 0.02, 0.05 ± 0.01, 0.03 ± 0.15, respectively; P < 0.01). Never- theless, mRNA expression of PAPP-A was much greater in Nellore (28.10 ± 18.96) than in Holstein (1.32 ± 0.17; P < 0.05). These results suggest that high expression of PAPP-A and low expression of IGFBP-2 and 4 could allow more efficiency on the degradation of IGFBP and increase the IGF bioavailability in the oocytes from Nellore as compared with Holstein cows. Satrapa, Simões, and Castilho received a fellowship and funding from FAPESP (São Paulo, Brazil).

Para melhor compreender as diferenças entre zebuínos e taurinos em relação à resistência ao ETC, objetivou-se verificar se a resistência ao ETC é resultado da contribuição genética do oócito, do espermatozoide ou de ambos. Oócitos de vacas das raças Nelore e mestiças com fenótipo predominante da raça Holandesa preto e branco (mHPB) foram coletados, maturados e fertilizados com espermatozoide de touros das raças Nelore (N), Angus (An), Brahman (Bra) e Gir (Gir). Noventa e seis horas pós-inseminação (hpi), embriões > 16 células foram separados ao acaso em dois grupos: controle e ETC. Embriões do grupo controle foram cultivados a 39 ºC continuamente e do grupo ETC expostos a 41 ºC por 12 horas, retornando a seguir para 39 ºC. Não foi observado efeito do ETC nas raças estudadas, sem redução nas taxas de blastocisto e blastocisto eclodido. As taxas de clivagem e mórula dos embriões mHPB x Gir foram inferiores (p < 0,05) às das demais raças. As raças mHPB x N apresentaram taxas de blastocisto superiores as raças mHPB x An e mHPB x Gir (p < 0,05). Concluiu-se que a contribuição genética do oócito é mais importante do que a do espermatozoide, uma vez que a raça do touro não influenciou a resistência embrionária ao ETC.

Heat shock (HS) has negative effects on pregnancy rates in lactating dairy cows. There are genetic differences in tolerance to HS, with Bos indicus cattle and embryos being more resistant to elevated temperatures than Bos taurus. Recently, Pegorer et al. (2007 Theriogenology 67, 692–697) observed that Gir semen (Bos indicus), when compared with Holstein semen (Bos taurus), increased pregnancy rates of lactating Holstein cows during the Brazilian summer. The objective of the present study was to evaluate the influence of breed of bull (Gir or Holstein) on the resistance of embryos to HS during the early stages of in vitro development. Oocytes from Holstein ovaries obtained from a local abattoir were matured in TCM 199 medium, fertilized with semen from 1 of 12 bulls (6 Gir and 6 Holstein), and cultured in synthetic oviduct fluid to the blastocyst stage. Ninety-six hours after insemination (96 hpi), embryos with less than 16 cells were discarded; half of the embryos (e16 cells) that were fertilized by each bull were submitted to HS (41�C for 12 h) and the other half (e16 cells) were maintained at 39�C (control group). After the HS period, embryos were maintained at 39�C until the end of the experiment. Six semen straws from different Gir bulls (Bos indicus) and 6 straws from Holstein bulls (Bos taurus) were used, in a total of 6 assays, to minimize the bull effect. Each breed of bull (Gir or Holstein) was used to fertilize a total of at least 300 Holstein oocytes per treatment (control v. HS). Cleavage (48 hpi), blastocyst (144 hpi), and hatched blastocyst (216 hpi) rates of embryos submitted or not submitted to HS were analyzed by PROC GLM of SAS (SAS Institute Inc., Cary, NC, USA) to adjust the model of ANOVA, with each combination of assays used as a block. The proportion data were arcsine transformed to study the effects of breed, treatment, and their interaction. There was no difference in cleavage rate when Gir semen was used to fertilize oocytes from Holstein cows (Gir � Holstein; 76.6%) as compared with Holstein � Holstein (75.5%). However, HS significantly decreased (P < 0.01) blastocyst rates (in relation to embryos e16 cells) from both Gir (74 and 62.6%, control and HS, respectively) and Holstein bulls (69 and 55%, respectively). The same was observed for hatched blastocysts from Gir (42 and 28.3%) and Holstein bulls (37 and 25%). Nevertheless, there was no interaction of breed of bull � treatment (HS) for blastocysts (P > 0.09) and hatched blastocysts (P > 0.1). It was concluded that the breed of bull used in the present experiment (Gir v. Holstein) did not increase the resistance of bovine embryos to HS at early stages of in vitro development.