Effect of dehydroepiandrosterone on meiotic spindle structure and oocyte quality in mice

Objective(s): Dehydroepiandrosterone (DHEA) has been reported to improve pregnancy chances in women with diminished ovarian reserve (DOR) and to reduce miscarriage rates by 50–80%. This study, therefore, assesses effects of DHEA on number of retrieved oocytes and meiotic spindles.Materials and Methods: A randomized, prospective, controlled study was conducted on eight groups, four groups of young mice and four elderly. All young and old groups received different oral doses (35, 50, 75 mg/kg) of DHEA for 3 months. Meiotic spindle assessment was done by immunocytochemical techniques using a confocal laser microscope (Leica TCS-4D).Results: Statistical surveys showed that in control young groups 80% (P=0.0845) and in the old control group 73.3% (P=0.000) of the meiotic spindles have a normal shape and structure; the difference was meaningful. The young with 50 mg/kg of DHEA in 85.4% and the young with 75 mg/kg of DHEA in 84.2% were normal in shape and structure. Statistical analysis showed that the difference was meaningless (P=0.845). The old group with 30 mg/kg of DHEA in 81.1%, the old with 50 mg/kg of DHEA in 83.9%, and the old with 75 mg/kg of DHEA in 79.0% showed normal shape and structure. The meiotic spindle disruption ratio in old mice showed a significant difference (P=0.000) in comparison with others in young groups. Statistical analysis showed that difference between DHEA and control groups is meaningful. But this difference was meaningless between DHEA groups.Conclusion: Results showed that DHEA has a positive and improvement effect on the meiotic spindle in old mice

Evaluating the Development and the Expression of Bax, Bcl-2, and ErbB4 Genes following Vitrification of Eight Cell and Blastocyst Embryos

Background & Objective: Vitrification is an effective mean for preserving embryos. During this process, expression of implanting and apoptotic genes changes and can affect the quality of embryos. In this study, the expressions of Bax and Bcl-2 as apoptotic genes and ErbB4 as implanting gene were investigated in vitrified and warmed embryos.  Materials & Methods: In this study, six-eight week old female (NMRI) mice were used. Their ovaries were hyper stimulated with 7.5 IU PMSG and 7.5 IU HCG. Females were mated with males from the same strain and inspected for the presence of vaginal plugs on the following morning. Females with the presence of vaginal plugs were considered to be pregnant and were killed 62 h post HCG injection. 8-cells embryos were flushed from oviduct and were divided to three experimental groups including fresh, vitrified eight-cell embryos and vitrified blastocyst embryos. Finally, RNA was extracted and expression of Bax, Bcl-2, and ErbB4 genes was evaluated by Real time PCR. Data were analyzed by Chi-square and ANOVA tests.  Results: The results of this study showed that there was not any significant difference in blastocyst formation and degeneration between three experimental groups. In addition, there was not any significant difference in relative gene expression of Bax, Bcl-2, andErbB4 between all the three groups.  Conclusion: According to the result of this study, vitrification-thawed process does not have any unpleasant effect on the development of eight cell and blastocyst embryos. It does not have negative effect on Bax, Bcl2, and ErbB4 genes expression

Fabrication of Mg/Al12Mg17 in-situ surface nanocomposite via friction stir processing

In this study, in-situ magnesium matrix surface nanocomposites were prepared by adding Al particles to an as cast pure Mg ingot using friction stir processing (FSP). The effects of the number of FSP passes, tool design, rotational and travel speeds were investigated. Microstructural investigations showed a significant grain refinement owing to dynamic recrystallization. According to scanning electron microscopy examinations and X-ray diffraction results, Al12Mg17 intermetallics were formed during FSP due to chemical reaction at the Al-Mg interface. As a result of severe plastic deformation, the intermetallic particles formed at nanometre size. X-ray diffraction showed that the crystalline size of intermetallic particles reached <= 50 nm, due to high material flow during FSP. The intermetallic formation and grain refining led to an increase in the hardness values 1.5-3 times) that of the as-cast pure Mg ingot.11Nsciescopu