title: Changes of intracellular free calcium during intracytoplasmic sperm injection.
abstract: The present experiments were undertaken to investigate whether the procedure of intracytoplasmic sperm injection (ICSI) is associated with changes in the intracellular free calcium concentration ([Ca2+]i). [Ca2+]i was measured, using the calcium-sensitive dye fura-2, during and after impalement of mouse oocytes with an ICSI pipette and injection of a small amount of medium alone or of medium containing a normal human spermatozoon. Forty-five oocytes were injected with medium. Two different responses were observed: 20 of these cells showed a large increase of [Ca2+]i upon impalement; the other 25 cells did not show any change of [Ca2+]i, neither in the acute period nor in a late period 4 hr after impalement. All the cells that responded with an increase of [Ca2+]i subsequently lysed within the first 30 min following impalement, while all the cells with no [Ca2+]i change remained intact. This observation suggests that only traumatic impalement is associated with an increase of [Ca2+]i. Thirty-one oocytes were successfully, i.e., without subsequent cell lysis, injected with a normal mouse or human spermatozoon. In none of these cells could any acute or late change of [Ca2+]i be observed. The experiments illustrate that successful performance of the ICSI procedure, i.e., ICSI not followed by cell lysis, is not associated with changes of [Ca2+]i in mouse oocytes. This suggests that the ICSI technique, by itself, does not help in activating the oocyte via manipulation-induced changes of [Ca2+]i.
authors.affiliation: Laboratory of Normal and Pathological Physiology, University of Ghent, Belgium.
authors.forename: L
authors.initials: L
authors.lastname: Leybaert
authors.forename: H T
authors.initials: HT
authors.lastname: Depypere
authors.forename: M
authors.initials: M
authors.lastname: Dhont
authors.forename: A
authors.initials: A
authors.lastname: de Hemptinne
mesh_terms: D000818:Animals; D002118:Calcium / Q000032:analysis / Q000378:metabolism*; D005260:Female; D008297:Male; D051379:Mice; D009865:Oocytes / Q000378:metabolism*; D013084:Sperm-Ovum Interactions
chemical_list: D002118:Calcium