Effect Of Ultrasound On Parthenogenic Activation Of Mouse Oocyte

Document Type : Original Article

Authors

1 Embryology Department, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran

2 Developmental Biology Department, University of Science and Culture, Tehran, Iran

3 . Reproductive Imaging Department, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran

4 Reproductive Imaging Department, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran

5 Genetics Department, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran

6 Iranian Center for Medical Lasers (ICML), Tehran, Iran

Abstract

Objective: Artificial stimulation of mouse oocyte, in the absence of sperm contribution, 
can induce its parthenogenic activation of oocyte. Ultrasound is one of the newest methods for artificial activation of mammal oocytes, and its successful utilization in pig oocyte 
activation has been recently reported. Our objective was to assess the effect of ultrasound 
on mouse oocyte activation.
Materials and Methods: Our groups included1 control group, 3 experimental groups consisting of 1, 2 and 3 repetitions of ultrasound exposure, and 3 sham groups handled similar 
to experimental groups but ultrasound system was off during treatments.
In experimental groups, adult female NMRI mice at the interval between pregnant mare 
serum gonadotropin (PMSG) and human corionic gonadotropin (hCG) injections, were 
exposed to continuous ultrasound with 3.28 MHz frequency and peak intensity (Ipk) = 355 
mW/cm2.
Sixteen hours after injection of hCG, the mice were euthanized and their oocytes were 
collected; thereafter, parthenogenic oocytes were counted.
Results: Data analysis using the ANOVA test shows a significant increase in the number of 
parthenogenic oocytes in mice with 3 overall exposures to ovarian ultrasound (p<0.05). 
A significant decrease in the number of metaphase II (MII) oocytes numbers was also 
seen in mice treated with ultrasound (p<0.05).
Conclusion: Ultrasound is thought to induce pores generation in oocyte membranes and 
provides an easier inward transport of Ca++ into oocytes. This phenomenon can induce 
meiosis resumption in immature oocytes. With increased exposure repetitions from 1 to 3 
times and greater Ca++ arrival, oocytes can be parthenogenetically activated.

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