Egg Windowing: A Method of Opening Fertilized Chicken Egg Shell to Expose Chorioallantoic Membrane Vasculature

Abstract

Source: Sharrow, A. C. et al. Using the Chicken Chorioallantoic Membrane In Vivo Model to Study Gynecological and Urological Cancers. J. Vis. Exp. (2020)

In this video, we describe a technique to open the eggshell of a fertilized chicken egg to expose its chorioallantoic membrane or CAM carrying a network of branching blood vessels. The exposed CAM can be used for in ovo tumor modeling.

Protocol

All procedures involving chicken egg embryos have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.

1. Preparing the eggs

1. Before receiving the eggs, assemble and equilibrate the egg incubator to 37.8 °C (100 °F) with 60-70% humidity following the manufacturer's instructions.
   NOTE: To minimize contamination risks, autoclaved water may be used to control the humidity.
2. Upon receiving fertilized Rhode Island Red chicken eggs from a certified laboratory-grade egg supplier, dry wipe the surface of the shells with paper towel....

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Roboz Surgical	RS6703		This is provided as an example. Any similar curved scissors would work as well.
Dremel	8050-N/18		This kit contains all necessary tools.
AA Lab Eggs Inc.	N/A		A local egg supplier would need to be identified, as this supplier only delivers regionally.
Incubator Warehouse	HB1588D-NONE-1102-1588-1357		Other egg incubators may be used, but their reliability would need to be verified. After implantation, a cell incubator with the CO2 disabled may also be used.
Incubator Warehouse	1102		Other candlers may be used; however, this is preferred among those that we have tested. This candler is included in the aforementioned incubator kit.
World Precision Instrument	15915		This is provided as an example. Any similar curved forceps would work as well. Multiple brands have been used for this method.
BD	305196		This is provided as an example. Any 18G needle would work similarly.
Fine Science Tools	11008-13		This is provided as an example. Any similar forceps or another style that suits researcher preference would be appropriate.
Electron Microscopy Sciences	72914		This is provided as an example. The forceps used for pulling away the shell for bioluminescence imaging are approximately 12.8 cm long with 3 mm-wide tips.
Fisherbrand	22-456-885		This is provided as an example. Any sterile cotton balls would suffice.
Moore Medical	21272
Corning	353803		This is provided as an example. Any similar, sterile 10-cm dish may be used. Tissue culture treatment is not necessary.
Tygon	AACUN017		This is provided as an example. Any similarly sized tubing would work as well.