The regeneration of smooth muscle during healing of urodele gut wounds☆

[摘要] AfterwoundingthewallofthepyloricendofthestomachofAmblystomapunctatumlarvae,completehealingandregenerationofthegutwalltissuestakesplacebythe30thpostoperativeday.Thefollowingobservationsandconclusionsaremade:1.1.Withinthefirstfewpostoperativedays,themucosalepitheliumcontactsthelateralbodywall,orinsomecasesadjacentabdominalviscera,andmigratesalongthiscontactsurfaceuntiltheadvancingedgesmeetandfusetocompletehealing.Later(22–30days),evaginationsoftheepitheliumreconstitutethesubmucosalglands.2.2.Ablastemaislaiddownexternaltothenewlyformedmucosalepitheliumandfillsthegapbetweenthecutedgesofthegutwall.Theblastemaishighlyvascularizedandiscomposedoffibroblastsandfibrocytesderivedfromconnectivetissueelementsof:(1)thesubmucosallayersofthegut,(2)lateralbodywall,or(3)otherareasofadhesionofthewoundedgut.Nodedifferentiatedcellsofthemucosa,smoothmuscle,orbodywallstriatedmusclecontributetotheblastemacellmass.3.3.Afterinitialaccumulation,theblastemagrowsbymitoticdivisionsofitscells.Itisorganizedbyalignmentofitscellsinaconcentricpatternperipheraltothemucosaandinlinewithandbridgingthegapbetweenthecutedgesoftheadjacentsmoothmusclelayer.4.4.Thecircularsmoothmusclelayerofthegutwallisreconstituted:(a)bydenovodifferentiationofblastemafibroblastsintosmoothmusclecells,and(b)bymigrationofintactsmoothmusclecellsfromthesmoothmuscleregionadjacenttothewoundregion.5.5.Theblastemaisthustransformedinsmoothmuscleandsubmucosalconnectivetissuesofthegutwall.Nodifferentiationofblastemacellsintomucosalepitheliumisobserved.

[学科分类] 生物科学（综合）