Histological and fine structural changes during chondrogenesis in micromelia induced by 6-aminonicotinamide☆
[摘要] Investigationsofdrug-inducedcongenitaldeformitycanleadtobetterunderstandingofdevelopmentalmechanisms.Ananalogofnicotinamide,6-aminonicotinamide(6-AN),giveninadoseof10μgtochickembryosonday4ofincubation,resultedinmicromeliaasdiagnosedbyreducedcartilageandbonein100%ofembryos.Histologically,chondrogeniccellsatday5werecompactlyarrangedandtheextracellularmatrixshowedreducedmetachromaticstainingwithtoluidineblue.Electronmicroscopyofthesecellsshowedadeficiencyofroughendoplasmicreticulumondays5and6withdilatedcisternaebyday8.IntheGolgiapparatusatday5,vacuoles,whichnormallycollectandtransportmucopolysaccharidestotheextracellularmatrix,weresmallorabsent.Degenerativechangesoccurredinthecoreofthechondrogenicrudimentondays5to8,whereascellsandmatrixsubjacenttothedevelopingperichondriumbyday7appearednormalinstainingandultrastructuralproperties.TheGolgiapparatusofchondrogeniccellswasatypicalbyvirtueofreducednumbersofcollectingvacuoles.Necrosisofthecentralregionofthechondrogenicrudimentwastransitory;thedamagetotherudimentwasincompletelyrepairedbysynthesisofmatrixbycellsneartheperichondriallayer.Theseobservationssuggestthatthelimbmalformationinducedby6-ANisbroughtaboutbyinhibitionofspecialsynthesisofmatrixbychondrogeniccellsinadditiontonecrosisofcorecellsofthechondrogenicrudiment.
[发布日期] [发布机构]
[效力级别] [学科分类] 生物科学（综合）
[关键词] [时效性]
