The Precursor Cells from the Inner Ear of SD Rats / 听力学及言语疾病杂志

ABSTRACT

Objective To investigate the influence on the proliferation of the precursor cells from the inner ear of SD rats by different ages and growth factors in vitro .Methods The organs of utricle or saccule or cochlear Corti were isolated from different days’ SD rats born on different days(P1 ,P7 ,P14 ,P21 ,P30 ,P60) .From 12 SD rats of different age ,with 24 ears ,precursor cells were dissociated and cultivated under non -adherent conditions as single cell .We then counted the number of cell spheres under inverted phase contrast microscope .The results were statisti-cally anayzed and the quantity change curve of the same organ in different age rats were described until the single cells were cultured for 7 days .The culture medium was supplemented with defferent growth factor to observe the effects of the grow th factor on the number of cell spheres .Immunofluorescence assays were conducted for phenotype characterization .Results ① Some newly isolated single cells ,labeled by nestin ,were from each inner ear organ of rats(P1) .During 7 days in culture ,cells kept proliferation and formed suspended spheres ,which were expressed Br-dU and nestin positive .② The cell spheres could only formed from each cochlear Corti of rats (P1 ,P7) .But cell spheres that formed from each utricle or saccule were observed in a single saccule culture medium of all rats (P1~P60) .③The number of cell spheres ,which were formed by the isolated cells from inner ear organs of single utricle or saccule or cochlear Corti ,increased obviously in the presence of EGF or bFGF or IGF -1 ,but were not obviously in LIF .Statistically significant differences were seen between control group and every experimental group including EGF group ,bFGF group ,IGF-1 group(P0 .05) .Conclusion The highly proliferative cells were present in the vestibular organ (utricle or saccule) and cochle-ar Corti of SD rats .They could express the characterization of neural stem cell .As increase of the age ,the overall trend of proliferative capability is declining .Each of EGF and bFGF and IGF -1 possess the promoting effects for proliferation on the precursor cells alone ,which is not in present of LIF .