Microinjection of Mouse Oocytes Using Impaling on Capillary Technique to Increase Survival Rate

Objective: Survival of oocytes subjected to injections is a critical parameter affecting cost efficiency, time of experiments and their reproducibility. A technique of microinjections into oocytes can be different, and often rely on an additional equipment simplifying the procedure for operator. The demand in protocols helping to increase oocytes’ survival rate drives a constant optimization of microinjection methodology. Methods: Here, we propose a protocol of injection into mouse oocytes that significantly increases the viability of eggs in comparison to common protocols and not requiring a special equipment. The main feature of our protocol is impaling an oocyte onto the tip of fixed injection needle by moving holding capillary. Another feature of proposed protocol is a simple procedure suitable for real time volume measurements during microinjections into germinal vesicle or mouse oocytes in metaphase II. Results and Discussion: The switch between moving capillary is allowing better oocytes’ survival rate in our hands. Method of measuring injected volumes does not require preliminary calibration of microinjecting system and can be used with capillaries of different tip shapes. Conclusions: Impaling on capillary technique allows decreasing eggs’ death and could be practiced in microinjection systems without special devices. Little error of measuring volume method suggests its using in cases of indicated solution volumes introduction in oocytes.