Control of corneal differentiation by extracellular materials. Collagen as a promoter and stabilizer of epithelial stroma production☆

[摘要] Theprimarystromaofthecorneaofthechickembryoconsistsoforthogonallyarrangedcollagenfibrilsembeddedinglycosaminoglycan(GAG)producedbytheepitheliumundertheearlyinductiveinfluenceofthelens.Theexperimentsreportedhereweredesignedtotestwhetherornotthecollagenofthelensbasementlaminaiscapableofstimulatingcornealepitheliumtoproduceprimarystroma.Enzymaticallyisolated5-day-oldcornealepitheliaweregrownfor24hrinvitrointhepresenceof35SO4orproline-3Honvarioussubstrata.Epitheliaculturedonlenscapsulesynthesized2.5timesasmuchGAG(asmeasuredbyincorporationoflabelintoCPCprecipitablematerial)andalmost3timesasmuchcollagen(assayedbyhotTCAextractionorcollagenasesensitivity)aswhenculturedonMilliporefilterorothernoncollagenoussubstrata.Asimilarstimulatoryresponsewasobservedwhenepitheliumwascombinedwithchemicallypurechondrosarcomacollagen,NaOH-extractedlenscapsule,vitreoushumor,frozen-killedcornealstromaorcartilage,ortendoncollagengels;inthelattercase,themagnitudeoftheeffectcanbeshowntoberelatedtoconcentrationofthecollageninthegel.Allofthecollagenoussubstratastimulatenotonlyextracellularmatrixproduction,butalsopolymerizationofcorneal-typematrix,asjudgedbyultrastructuralcriteriaandbytheassociationofmoreradioactivitywiththetissuethanthemedium.Sincepurifiedchondrosarcomacollagenisaseffectiveaslenscapsule,thestimulatoryeffectoncollagenandGAGsynthesisbycornealepitheliumisnotspecificforbasallamina(lenscapsule)collagen.

[学科分类] 生物科学（综合）