The effect of coenzyme Q10 on cryotolerance of in vivo-derived mouse embryos.

OBJECTIVE: Cryopreservation has some adverse effects on embryos including cell metabolism reduction, mitochondria and plasma membrane damage, excess production of 'Reactive Oxygen Species' and damage to DNA. In the present study. In this study we assessed the effect of coenzyme Q10 as an exogenous antioxidant on mouse embryos following cryopreservation. METHODS: We collected mice embryos at the morula stage from uterine horns on the third day of gestation. The morulae were divided into 9 groups (1 control, 2 vehicles and 6 experimental), then vitrified. The culture and/or vitrification media of the experimental groups were supplemented by 10 or 30 µM of CoQ10. After one week, the embryos were warmed and then cultured. After 48 hours of embryo culture, the blastocyst rate, total cell number, viability; and after 72 hours of embryo culture, we assessed the hatching rate. RESULTS: Blastocyst rate and hatching rate were significantly reduced in the groups containing 30 µM CoQ10 supplemented culture media compared to other groups (p<0.05). The hatching rate in the groups containing 10 µM CoQ10 supplemented in both culture and vitrification media was significantly higher than in the other groups (p<0.05). In groups containing 10 µM CoQ10 supplemented culture media, the viability was higher than that in the other groups (p<0.05). CONCLUSIONS: It seems that CoQ10 in a dose-dependent manner is able to improve hatching rate and viability following cryopreservation through its antioxidant and anti-apoptotic properties, and through the production of ATP.

Characterization of embryonic surface ectoderm cell protrusions.

BACKGROUND: During embryonic development, complex changes in cell behavior generate the final form of the tissues. Extension of cell protrusions have been described as an important component in this process. Cellular protrusions have been associated with generation of traction, intercellular communication or establishment of signaling gradients. Here, we describe and compare in detail from live imaging data the dynamics of protrusions in the surface ectoderm of chick and mouse embryos. In particular, we explore the differences between cells surrounding the lens placode and other regions of the head. RESULTS: Our results showed that protrusions from the eye region in mouse embryos are longer than those in chick embryos. In addition, protrusions from regions where there are no significant changes in tissue shape are longer and more stable than protrusions that surround the invaginating lens placode. We did not find a clear directionality to the protrusions in any region. Finally, we observed intercellular trafficking of membrane puncta in the protrusions of both embryos in all the regions analyzed. CONCLUSIONS: In summary, the results presented here suggest that the dynamics of these protrusions adapt to their surroundings and possibly contribute to intercellular communication in embryonic cephalic epithelia.

Androgen receptor is expressed in mouse cardiomyocytes at prenatal and early postnatal developmental stages.

BACKGROUND: Previous studies show that androgens are involved in hypertrophy and excitability of cardiomyocytes and that their effects are mediated through their receptor. The aim of this study was to evaluate the presence of androgen receptor (AR) in mouse heart during prenatal and early postnatal stages. RESULTS: The expression of AR and related genes, alpha myosin heavy chain -Myh6-, beta myosin heavy chain -Myh7- and atrial natriuretic factor -Nppa- was simultaneously evaluated by semiquantitative RT-PCR. AR was also detected by immunohistochemistry. Androgen receptor mRNA was detected in hearts from 10.5 days post coitum to 16 postnatal days. A higher expression of AR mRNA in atria compared to ventricles was observed in neonatal mouse. A positive correlation between mRNA levels of AR and Nppa was observed in mouse heart at early postnatal development. Androgen receptor expression is similar in males and females during cardiac development. Finally, androgen receptor protein was observed by immunohistochemistry in myocardial cells of atria and ventricles from 12.5 days onwards and restricted after 16.5 days post-coitum to nuclei of cardiomyocytes. CONCLUSION: Present results provide evidence that androgen receptor is expressed from prenatal stages in mouse heart, supporting the proposition that androgens could be involved in mammalian heart development.

Oxidative stress and cellular and tissue damage in organogenic outbred mouse embryos after moderate perigestational alcohol intake.

Perigestational alcohol consumption by CF-1 mouse, from before mating up to the period of embryo organogenesis, leads to retarded early embryo development and neural tube defects. Here, we addressed if perigestational alcohol ingestion up to Day 10 of pregnancy induces oxidative stress and changes in macromolecules and organ tissues of early organogenic embryos. Adult CF-1 female mice were administered 10% ethanol in their drinking water for 17 days prior to mating and until Day 10 of gestation, whereas control females were administered ethanol-free water. Our results demonstrated significantly reduced Catalase abundance and activity and increased glutathione content in the embryos of ethanol-treated females. The nitrite level was significantly reduced, but TBARS (thiobarbituric acid reactive substances) content, an index of lipid peroxidation, did not change. Embryos derived from ethanol-treated females also showed higher abundance of 3-nitrotyrosine (3-NT)-containing proteins in all tissues, compared to the control group. Apoptosis was significantly increased in the ectoderm and mesoderm, but not in the heart-although this organ did contain more cleaved Caspase-3-positive cardiomyocytes per area of ventricular myocardium than controls. In sum, moderate perigestational alcohol ingestion up to Day 10 of gestation in mice induces oxidative stress by altering radical nitrogen species and antioxidant enzymatic and non-enzymatic mechanisms in embryos. Further, generalized protein nitration, due to unbalanced nitric oxide levels associated with tissue-specific apoptosis, was detected in embryos, suggesting that oxidative mechanisms may play an important role in the perigestational alcohol-induced malformation of organogenic embryos exposed to ethanol.

Effect of vitrification on viability and chromosome abnormalities in 8-cell mouse embryos at various storage durations

This study was desµgned to investµgate the effect of vitrification and post-thaw survival and chromosomal aberrations caused by vitrification of vitrified 8-cell mouse embryos in comparison with a controligroup. To this purpose the survival rate and the frequency of chromosomal aberrations were assessed in frozen-thawed 8-cell mouse embryos after various storage durations in the presence of ethyleneiglycol as cryoprotectant. eight-cell mouse embryos were obtained from NMRI mice 3 days after mating. Retrieved embryos were transferred to vitrification solution containing ethyleneiglycol as cryoprotectant, then transferred into a vitrification straw using standard technique, and vitrified in liquid nitrogen. Sixigroups of embryos according to storage duration (24 hours, 1 and 2 weeks, 1-6 months) were frozen. After appropriate storage periods embryos were thawed and studied for their viability 4-6 hours after thawing and intact embryos were transferred to fresh medium containing colcemid. After 48 hours, the embryos were fixed and studied for their chromosome abnormalities using Tarkowsky's drying technique. Results indicate that freezing affects the viability and chromosome structure of embryos when compared with the controligroup. Furthermore increasing the storage duration reduces the viability and increases the chromosome aberrations of embryos (such as aneuploidy and polyploidy). This result mµght indicate that the effects of vitrification on the cytoskeleton or other cellular organelle mµght produce chromosomal alterations leading to cell death.