IsolationofLungBudEndoderm Whatyouneed: 1.DissectE11-12lungsinDMEMand5%serumonice.Younglungs(E11to11.5)arebest. 2.Washthelungs3x5minutesoniceinTyrode-Ringer\"sSolution,pH7.6-7.7tooptimizephysiologicalconditionsforpancreatin-trypsinactivity. 3.Incubatewholelungsforappoximately5minutesinpancreatin-trypsinsolutiononice.ThetimerequiredwillvarydependingonthebatchofPT. 4.Washlungs3x5minutesinDMEM+serumtosaturatepancreatin-trypsinactivity. 5.Usingtungstenneedles,dissectoffthemesenchymeandcutoffthebuds.Alternatively,cutoffthebudsfirstandremovethemesenchymesurroundingthem. 6.Placeintomatrigelmatrixandcultureforthreetofivedays(seeaccompanyingprotocol).Isolatedendodermwillnotsurvivewithoutgrowthfactoraddedtotheculturemedium. Tyrode-Ringer\"sSolution,pH7.6-7.7 componentg/liter Pancreatin/TrypsinSolution componentg/20mlfinalconcentration SUSPendbymixingforabout30minutes.Centrifugeat3000XgintheSorvallhangingbucketrotorfor5minutes.Filtersterilizethesupernatantusing.8micronMilliporefilter(s).Storeinaliquotsat-80C.Thisprocessisabigpainandtimeconsuming,mainlybecausethesupernatantdoesnotfilterefficientlyandtheMilliporefiltersmustbeswitchedoften. Whatyouneed: Tissuestobeculturedareplacedinto50uldropsofcollageninfour-wellNuncdishes.Foreachtreatment,makeaseparate50ulaliquotofcollagengelasdescribedintheprotocolbelowandstoreonice.Directlybeforeaddingsamples,addtheNaHCO3andmixwell.ItisnecessarytoprepareeachcollagengelseparatelybecauseadditionofNaHCO3makesthecollagenpolymerizequickly. 1.Placecollagen,10XDMEMandonice.Alsochillthefour-welldishesintherfridgebeforeuse. 2.Mix45ulcollagenand5ul10XDMEM.Mixwellonice.Thecollagenwillnotgelifkeptcold. 3.Add1.9ulofNaHCO3.Mixwell.Thisstepbeginspolymerizationofthecollagengel. 4.Addthe50ulcollagenmixturetoachilledfour-welldish. 5.Firstprepareabedofcollagenandallowittosetat37篊.Afterithaspolymerized,addyoursampletothebedofcollagenandaddcoldunpolymerizedcollageninalayeroverthetopofthesample. 6.Placeat37篊forapproximately10minutestoallowcompletepolymerization.Solutions
CollagenGels