Laser zona drilling does not induce hsp70i transcription in blastomeres of eight-cell mouse embryos

To assess whether zona drilling with a 1,480-nm laser induces heat shock in eight-cell embryos, we measured hsp70i RNA levels in sets of single blastomeres isolated after laser treatment of mouse embryos that had or had not been heated at 43°C. Unlike heating, laser zona drilling did not stimulate hsp70i expression, even in the blastomeres closest to the laser beam, corroborating the safety of this procedure for assisted reproduction.