Subzonal fertilization of mouse round spermatids.

Area of Science:

• Reproductive Biology
• Developmental Biology
• Cell Biology

Background:

• Spermatid injection into oocytes is a method to study male gamete development.
• Understanding nuclear behavior post-fusion is crucial for assessing developmental potential.

Purpose of the Study:

• To investigate the fusion of mouse round spermatids with mature oocytes.
• To evaluate the nuclear behavior and developmental capacity of fused cells.
• To optimize electrofusion parameters for successful round spermatid-oocyte fusion.

Main Methods:

• Round spermatids were injected into the perivitelline space of mature oocytes.
• Electrofusion was achieved using alternating current (AC) and direct current (DC) pulses.
• Fused oocytes were cultured to assess pronuclear development and subsequent embryonic development.
• Calcium ion concentration in the fusion medium was varied to assess its effect.

Main Results:

• A high survival rate (89.0%) and fusion rate (61.9%) of round spermatid-oocyte pairs (RS-O) were achieved.
• 49.2% of fused oocytes developed to the two-pronuclear (2PN) stage.
• Optimal fusion parameters were identified using specific AC and DC pulse conditions.
• 32.6% of 2PN oocytes exhibited fully developed male and female pronuclei.
• 12 offspring were produced following the transfer of 192 fertilized eggs.

Conclusions:

• Electrofusion of mouse round spermatids with oocytes is an effective method for generating viable embryos.
• The study identified optimal electrofusion parameters and assessed developmental outcomes.
• This technique holds promise for reproductive research and potential applications in assisted reproduction.