Differences in resistance against osmotic challenge among C57BL/6, DBA/2 and their hybrid mice metaphase II (MII) stage oocytes

Abstract

SummaryOocytes of B6D2F1 (BDF1) mice are often used as recipients for intracytoplasmic sperm injection because of their cell membrane resistance against capillary penetration. It is assumed that oocytes of BDF1 mice have superior traits because of their hybrid vigour. However, the mechanisms of hybrid vigour are unclear. In this study, we focused on the membrane resistance of MII stage oocytes against changes in extracellular osmotic pressure. As a result, MII stage oocytes of inbred C57BL/6 and DBA/2 mice showed high tolerance in either a hypertonic or a hypotonic environment. Conversely, MII stage oocytes of hybrid BDF1 and D2B6F1 mice showed high tolerance in both hypertonic and hypotonic environments. Therefore, it is considered that MII stage oocytes of hybrid mice have superior traits than those of inbred mice. Our findings demonstrated that the hybrid vigour exists in the form of resistance to extracellular osmotic environment in hybrid MII stage oocytes.

Protective effect of onion peel extract on ageing mouse oocytes

“…The results showed that high concentrations (200 and 500 μg/ml) of OPE increased the fragmentation rate, and all oocytes died after treatment with 500 μg/ml OPE. This may be attributed to the openness being a mixture that causes a change in the osmotic pressure of the medium, causing irreparable damage to the oocytes (Goto et al, 2019). However, there was no significant difference in oocyte fragmentation rate between the ageing group and the low OPE concentration (50 and 100 μg/ml) groups.…”