Effect of 4-methylumbelliferyl-β-d-xyloside on collagen synthesis in chick limb bud mesenchymal cell cultures☆

[摘要] Previousstudiesshowedthatculturesofchicklimbbudmesenchymalcellsplatedathighdensity,tomaximizechondrogenicexpression,hadamuchreducedextracellularmatrixaroundchondrocyteswhenexposedto4-methyl-,umbelliferyl-β-d-xyloside.Themajorityofnewlysynthesizedchondroitinsulfatechainswerefoundintheculturemediumpresumablyboundtothexylosideasopposedtotheirnormaldepositiononthecoreproteinofproteoglycan.Thequestionremainedopenastowhetherthedevelopmentofanabnormalmatrixaffectedthesynthesisofextracellulardepositionofothercartilage-specificmacromolecules.Wehaveanalyzed,bothmorphologicallyandbiochemically,thesynthesisanddepositionofTypeIandTypeIIcollagenbyβ-d-xyloside-treatedculturesoflimbmesenchymalcells.Whiletherateofcollagensynthesisperplateanditsextracellularaccumulationafter8daysinculturewerereducedtosomeextent,theratiosofTypeIItoTypeIcollagenandthemorphologicaldistributionofthesemacromoleculeswerenotaffectedbyexposuretoβ-d-xyloside.Weconcludethattheexpressionofthecartilage-specificTypeIIcollagenduringchondrogenicdifferentiationis,althoughreduced,qualitativelynotdependentontheamountofextracellularchondroitinsulfatechainsattachedtomatrix-associatedproteoglycancoreprotein.However,prolongedexposureoflimbbudcellstoxylosidesleadstotheformationofachondroitinsulfate-andcollagen-deficientmatrixwhich,inturn,reducesthecapacityoflimbbudcellstosynthesizeTypesIandIIcollagen.

[学科分类] 生物科学（综合）