Ciliaryneurotrophicfactoristheonlyknownneurotrophicfactorthatcanpromotedifferentiationofhippocampalneuralprogenitorcellstoglialcellsandneuronsinadultrats.Thisprocessissimilartospontaneousdifferentiation.Therefore,ciliaryneurotrophicfactormaybeinvolvedinspontaneousdifferentiationofneuralstemcells.Toverifythishypothesis,thepresentstudyisolatedneuralprogenitorcellsfromadultmaleratsandculturedtheminvitro.Resultsshowedthatwhenneuralprogenitorcellswereculturedintheabsenceofmitogenfibroblastgrowthfactor-2orepidermalgrowthfactor,theyunderwentspontaneousdifferentiationintoneuronsandglialcells.Westernblotandimmunocytochemicalstainingshowedthatexogenousciliaryneurotrophicfactorstronglyinducedadulthippocampalprogenitorcellstodifferentiateintoneuronsandglialcells.Moreover,passage4adulthippocampalprogenitorcellsexpressedhighlevelsofendogenousciliaryneurotrophicfactor,andaneutralizingantibodyagainstciliaryneurotrophicfactorpreventedthespontaneousneuronalandglialdifferentiationofadulthippocampalprogenitorcells.Theseresultssuggestthatthespontaneousdifferentiationofadulthippocampalprogenitorcellsismediatedpartiallybyendogenousciliaryneurotrophicfactor.
