Follicle Development in Grafted Mouse Ovaries after Vitrification Processes Under Static Magnetic Field.

BACKGROUND: Ovarian cryopreservation has emerged as an important method of fertility preservation. Magnetic field enhanced cryopreservation has been considered in recent times as a promising type of ovarian cryopreservation but the effectiveness of the process is still not clear. OBJECTIVE: The aim of the present study was to investigate the effect of applying 1-mT SMF (static magnetic field) on the vitrification of ovarian tissue and the follow-up investigation of the morphology and functions of vitrified- warmed ovarian tissue after transplantation. MATERIALS AND METHODS: Ovaries of 6-8 week-old female mice from the Naval Medical Research Institute (NMRI) were exposed of the static magnetic field during different steps of the vitrification process. Immunohistological studies were performed on the ovaries. RESULTS: The mean percentage of damaged primordial follicles was lowest in control group and the group with ovaries exposed to magnetic field during the equilibration step. The latter group also had the highest percentage of intact primordial follicles after transplantation. CONCLUSION: Exposure of mice ovaries to static magnetic field during first step of vitrification process (the equilibration step) resulted in greater resistance against injury.

Effect of therapeutic ultrasound on folliculogenesis, angiogenesis and apoptosis after heterotopic mouse ovarian transplantation.

One of the challenges in ovarian transplantation is ischemia-reperfusion damage. When transitional tissue faces an acute and critical condition in terms of blood supply (immediately after organ transplantation), treatment with low-intensity pulsed ultrasound (LIPUS) seems to be very beneficial. The aim of this study was to evaluate the effects of ultrasound therapy on heterotopic transplanted mouse ovarian tissue. Adult female Naval Medical Research Institute mice were divided into three groups. In the experimental groups, the transplanted ovary was exposed 5 min daily to ultrasound with an intensity of 0.3 W/cm(2), frequency of 3 MHz and pulse mode of 1:4. The grafted ovaries were assessed with the usual histology and immunohistochemistry techniques. Results indicate that more CD31 angiogenic factor was expressed in irradiated animals than in control animals, and ultrasound therapy resulted in better follicular preservation, especially after 14 d. In conclusion, therapeutic ultrasound may accelerate and increase re-angiogenesis and can help to promote ovarian follicular growth.

Effect of mono-(2-ethylhexyl) phthalate (MEHP) on resumption of meiosis, in vitro maturation and embryo development of immature mouse oocytes.

The purpose of this study was to evaluate the effect of MEHP on in vitro maturation of mouse oocytes and resulting embryo development. Denuded oocytes (DO) were cultured in maturation medium supplemented with 0, 50, 100, 200 and 400 microM levels of MEHP for 24 h. The matured oocytes then were fertilized and cultured for 4 days. The percentage of Germinal Vesicle (GV) stage oocytes were significantly higher in 200 and 400 microM MEHP treatment comparing to the control (P < 0.05). The proportion of oocytes that progressed to the metaphase II (MII) stage was significantly decreased by adding of MEHP in a dose related pattern. The 2-cell embryo formation was significantly decreased with 400 microM treatments than the control. Moreover with further culture in experimental groups none of the embryos comparing to that of the control group were developed to morulla stage (P < 0.05). These results indicate that MEHP could negatively modulate mouse oocyte meiotic maturation in vitro and embryo development, suggesting possible risks for human and other mammalians reproductive health.

Survival rate of preantral follicles derived from vitrified neonate mouse ovarian tissue by Cryotop and conventional methods.

The aim of this study was to investigate the growth and survival rate of preantral follicles isolated from vitrified ovarian tissue by Cryotop and conventional methods. The ovaries of 14-day-old mice were separated and divided into four groups as following: Cryotop group, vitrified by Cryotop; CV (Conventional; CV) group, vitrified by conventional straw; toxicity test group and control group. After warming the vitrified ovaries, isolated preantral follicles from four groups were cultured for 4 days to compare survival rate and follicular growth between above-mentioned groups. Survival rate (97.3%) in toxicity test group alike the control group (98.7%) were significantly higher (P<0.05) than the Cryotop (92.7%) and CV (47.7%) groups. Increase in follicle diameters after 4 days in Cryotop and CV groups was significantly lower (P<0.05) than the control and toxicity test groups, but growth and survival rate of follicles in Cryotop group was significantly higher (P<0.05) than the CV group. These results demonstrated that ovarian tissue vitrification by Cryotop highly preserves the viability rate of preantral follicles.