Cytodifferentiation and embryogenesis in cell colonies and tissue cultures derived from ova and blastocysts of the rabbit☆

[摘要] Theabilityofcellsfromvariousstagesofpreimplantationrabbitembryostoformcoloniesinvitrohasbeenstudied,withaviewtoobtaininglargepopulationsofembryoniccellswhichretainacapacityforfurtherdifferentiationinresponsetospecificstimuli.Whenthezonapellucidawasleftintact,allcleavagestagesdevelopedtoblastocysts.Afterenzymaticremovalofthezonapellucidaseveralcleavagesoccurred,thenumberincreasingwiththeageoftheembryo.Incoloniesderivedfrommorulae,differentiationoftrophoblasticcellswhichattachedtothesubstratumoccurred,andembryoniccellsformedasmallmassontopofthese.Cleavagealsocontinuedinblastomeresofembryosdisaggregatedwithtrypsin.Coloniesofunattachedcellswereformed,orspontaneousreaggregationintomorulaeandsubsequentblastocystformationoccurred.When,afterenzymaticremovalofthezonapellucida,adhesionofblastocyststothesubstratumwasencouraged,thetrophoblastcellsspreadoutinaflatsheetleavingtheembryonicdiscontheuppersurface.Theembryoniccellsmultipliedandmigratedoverthetrophoblasticlayeranddifferentiationofcelltypesoccurred.Thesecellwereunabletomigratebeyondthetrophoblastandnonebecamepermanentlyestablishedinculture.Cellsfromtheembryonicdiscwereshowntobeunabletoattachtoinorganicsubstratabutabletoattachtoandmultiplyonreconstitutedcollagen.Whenembryonicdiscswerefreedfromtrophoblastandexplantedontothissurface,densehomogeneousmassesofcellsdeveloped,fromwhichinafewinstancesmonolayersofcellsmigratedout.Aftertrypsinizationsomeoftheseoutgrowthshavegivenrisetoprimarycellcultureswhichcanbemaintainedandseriallytransferredinvitro.Primarycellstrainshavealsobeenestablishedfromsinglecellsuspensionsobtainedbydisaggregatingisolatedembryonicdiscsandplatingontocollagencoatedsurfaces.Severalprimarycellstrainsdifferinginbothmorphologicalappearanceandsomebiochemicalfeatureswerederivedinthesewaysandarebeingkeptincontinuousculture.Somehavecontinuedtodividerapidlyandhaveremainedeuploidaftermanymonthsinculture.

[学科分类] 生物科学（综合）