High oxygen levels during in vitro culture (IVC) can induce oxidative stress through accumulation of reactive oxygen species (ROS), negatively affecting embryo development. This study evaluated the effect of different O2 tensions during IVC on bovine blastocyst development and transcriptional status, considering transcription factors that play an essential role during early embryo development. For this purpose, embryos were produced in vitro by conventional protocols and cultured in two different oxygen tensions, physiological (5%) and atmospheric (20%). Expanded blastocysts were subjected to transcript quantitation analysis by RT-qPCR with Biomark™ HD System (Fluidigm, US), using 67 TaqMan assays specific for Bos taurus. Differences were observed in genes related to oxidation-reduction processes, DNA-dependent transcription factors, and factors related to important functional pathways for embryo development. Blastocyst rate was higher in the 5% O2 group and the number of cells was assessed, with the 5% O2 group having a higher number of cells. ROS concentration was evaluated, with a higher ROS presence in the 20% O2 group. Taken together, these results allow us to conclude that IVC of embryos at atmospheric O2 tension affects the expression of important transcription factors involved in multiple cell biology pathways that can affect embryo development, quality, and viability.

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SummaryDespite sperm mitochondrial relevance to the fertilization capacity, the processes involved in the production of ATP and functional dynamics of sperm mitochondria are not fully understood. One of these processes is the paradox involved between function and formation of reactive oxygen species performed by the organelle. Therefore, this review aimed to provide data on the role of sperm mitochondria in oxidative homeostasis and functionality as well the tools to assess sperm mitochondrial function.

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Cystic endometrial hyperplasia–pyometra complex is a canine endometrial disorder, considered the most common and important among uterine diseases. The treatment of choice is ovariohysterectomy, but medical treatments have become an alternative. However, no studies have been performed in order to evaluate uterine hemodynamic changes during medical treatment for pyometra bitches. Therefore, the aim of this study was to compare the effectiveness of two medical protocols by means of clinical (heart rate, respiratory rate and body temperature), medullar response (complete blood count (CBC)) and uterine hemodynamic evaluation in pyometra bitches. For such purpose, 10 bitches with pyometra were assigned to two groups: Aglepristone Group (n = 5) and Associative Group (aglepristone + prostaglandin; n = 5). The Associative Group had altered respiratory rate and decreased body temperature. The Aglepristone Group had decreased plasma protein, however, leukocyte count reduced over time for both therapeutic protocols. Uterine area and vascularization score decreased throughout treatment. There was a significant reduction in uterine perimeter, area and vascularization score. The Associative Group had lower final diastolic velocity and higher systole:diastole ratio (S/D), pulsatility index (PI) and resistance index (RI). In conclusion, both medical treatments are effective in reversing clinical and CBC changes of pyometra, especially aglepristone, however they cannot fully restore local uterine changes in a short-term evaluation. Conversely, associative therapy was more effective in decreasing uterine vascularization and modulating uterine blood flow.