This study compares four trophectoderm microbiopsy techniques for removal of blastomeres from murine blastocysts: (1) aspiration,trophectoderm pipetted through the zona; (2) incision,trophectoderm excised with a microrazor; (3) slit/excision,the zona slit and herniating trophectoderm excised; and (4) hatch/excision,trophectoderm cells excised after spontaneous hatching.
Murine blastocysts were comparatively biopsied using one of four methods and contrasted to zona slit and nonmicromanipulated controls. Operative cellular injury was assessed by uptake of fluorescein isothiocyanate (FITC). Postoperative embryonic viability was assessed by blastocoele reexpansion and hatching inner cell mass development and trophectoderm plating. All techniques yielded cells available for genetic analysis.
The slit/excision technique and hatch/excision techniques exhibited lower operative injury and the higher postoperative viability than aspiration or incision. The slit/excision and the hatch/excision techniques, though requiring two operative steps, appear to be the least damaging of the four methods. Therefore, they should be most applicable to human blastocysts obtained either by extended culture in vitro or by uterine lavage.
blastocysts blastomere biopsy murine human preimplantation diagnosis