Inhibition of cartilage development in organ cultures of chick somites by the thymidine analog, 5-bromo-2′-deoxyuridine☆

[摘要] Organculturesofstage17–18chicksomiteswithorwithoutnotochordwereexposedto5-bromo-2′-deoxyuridine(BUdR)at0–3,1–4,2–5,and3–6days,reincubatedinBUdR-freemedium,andassayedfortheappearanceoffunctionalchondroblasts10–20dayslater.Inallorgancultures,exposuretoBUdRfromday0today3preventedtheappearanceofmethyleneblue-stainingcartilagenodules.DelayingtheBUdRexposureallowedincreasingnumbersofcartilagepositiveculturestoappear.ExposuretoBUdRondays0to3alsoinhibitedthesubsequentincorporationofglucosamine-3Horsulfate-35Sintochondroitin4-sulfateassayedbyhigh-voltageelectrophoresis.Intheseculturessynthesisofhyaluronicacidandaglycoproteincomponentwasrelativelyunaffected.AttemptsweremadetorecoverfunctionalchondrocytesfromBUdRtreatedorganculturesbydissociatingthecellsandgrowingthemasmonolayers.NochondrogeniccoloniesappearedinprimarysubculturesoforganculturestreatedwithBUdRfrom0to3days,andfewchondrogeniccoloniesemergedfromsecondarysubcultures.OrganculturestreatedwithBUdRatlaterperiods,whensubcultured,producedincreasingnumbersofchondrogeniccolonies.ItispostulatedthatincorporationofBUdRfrom0to3dayspreventstheshiftfromthesclerotomephenotypetothechondrogenicphenotype.BUdRresistanceinolderculturesmayreflectthegradualwithdrawalofchondrogeniccellsfromthemitoticcycle.

[学科分类] 生物科学（综合）