ISSN:
1040-452X
Keywords:
A23187
;
In vitro maturation
;
lonophore
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
Notes:
These studies were conducted to examine activation of in vitro-matured porcine oocytes in response to an electrical stimulus or to an ionophore. Cumulus-enclosed porcine oocytes were incubated in maturation medium supplemented with either FSH and LH (MM:Exp.1) or pregnant mare serum gonadotropin (PMSG; MMP: experiments 2-4) at 39°C in 5% CO2:95% air with high humidity. In experiment 1, groups of oocytes were stripped of cumulus and then shampulsed (control) or electrically pulsed with a Zimmerman Cell Fusion unit at 24, 31, 41, 48, and 65 h of incubation. Control oocytes were exposed to the activation medium for 20 sec, whereas oocytes to be pulsed were subjected to a single activation pulse (120 V, 30 μsec). Oocytes were cultured for an additional 24 h and then fixed and examined. For oocytes pulsed at 24, 31, 41, 48, and 65 h, the proportions which activated were 0, 0, 87, 88, and 83%, respectively. In experiment 2, oocytes were electrically or sham-pulsed with a BTX 200 Embryomanipulation System at 24, 30, and 40 h of incubation and respective proportions of oocytes activating were 27%, 39%, and 72%. In experiment 3, oocytes were subjected to 0, 1, or 2 activation pulses after 41 h of incubation in MM-P. Double-pulsing halved the proportion of activated oocytes (P〈.0001). In experiment 4, oocytes were subjected to 0, 25, 50, or 100 μM ionophore at 48 h of incubation. Proportions of oocytes activated by ionophore were greater than for control (P 〈 .05), but activation was not increased by increasing dose of ionophore. These results indicate that porcine oocytes may respond to an activation stimulus by 24 h of incubation, long before maturation is normally completed. Activation can be achieved also with an ionophore, as described previosly for other species.
Additional Material:
1 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrd.1080280111
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