An Effective Chemical Permeabilization of Silkworm Embryos

Area of Science:

• Insect reproductive biology
• Developmental biology
• Cryobiology

Background:

• Insect eggs possess a protective lipid layer on the vitelline membrane, crucial for waterproofing and desiccation resistance.
• This lipid layer impedes chemical penetration, hindering cryoprotectant influx essential for successful insect embryo cryopreservation.
• Permeabilization methods for silkworm (Bombyx mori) embryos are not well-established.

Purpose of the Study:

• To develop an effective permeabilization method for removing the lipid layer of Bombyx mori embryos.
• To investigate factors influencing the viability of dechorionated embryos post-treatment.
• To optimize conditions for enhanced chemical permeability and embryo survival.

Main Methods:

• Developed a permeabilization technique to remove the lipid layer from Bombyx mori embryos.
• Evaluated the efficacy of different chemicals (hexane, heptane, Triton X-100, Tween-80) for permeabilization.
• Assessed the impact of chemical exposure times and embryonic developmental stages (e.g., 160 vs. 166 hours after egg laying at 25 °C) on embryo viability.

Main Results:

• Hexane and heptane proved effective for lipid layer permeabilization, while Triton X-100 and Tween-80 showed lower efficacy.
• Significant differences in viability were observed between embryos at 160 and 166 hours after egg laying (AEL).
• Optimal permeabilization was achieved by treating 160 AEL embryos with hexane for 30 seconds, resulting in over 62% developing to the second larval instar.

Conclusions:

• The developed hexane-based permeabilization method is effective for silkworm embryos.
• Optimized treatment conditions (160 AEL, hexane, 30s) significantly enhance embryo viability and developmental potential.
• This method provides a foundation for further research in chemical permeability studies and cryopreservation of Bombyx mori embryos.