A study of development in organ cultures of mammalian lungs☆☆☆

[摘要] Explantsoflungsfrom16littersoffetalrats(13–19days)andfromthreelittersoffetalguineapigs(27,30,and60days)weregrownasorgansonsolidmediacontaining40%serum,glucose,and1.5%agar.Mostcomponentsofthelungsdeveloped,thoughgrowthofthevasculartreewasrestricted.Thecolumnarepitheliumoftheearlylungsprogressivelybecamelowerasbranchingproceededandinsomeculturesevenattenuatedsharplyatpointswherealveolus-likeportionsdifferentiated.Mitoticratesinculturesfromslowlydevelopingguineapigswerecomparabletosimilarlyagedlungsinvivobutinratswereconsiderablydiminished.Glycogenconcentratedinthebuddingterminalepithelium,wheremitosesweremostfrequent,anddisappearedafterformationoftheflattened“alveolar”lining.Otherhistochemicalpatternsseeninvivowerealsocloselyreproducedinvitro.Comparableresultsinmorphologyandhistochemistrywereobtainedinexplantsgrownwithaddedcyanideormalonate,butallculturesfailedwhengivenfluoride.Thus,nearlyfullpotentialfortheformationoflungsiscontainedwithintheexplants,differentiationsoccurindependentofgrowth,andanaerobicmetabolismchieflysuppliesthedevelopingorgan.Theseconclusionsareweighedinthediscussion,alongwithsomeemergentspeculationondevelopmentalmechanismsoperatinginthelungs.

[学科分类] 生物科学（综合）