Isolation and Culture of Adult Neural Stem Cells from Guinea Pig Tympanic Membrane / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Tympanic membrane perforation is an important clinical problem found in various populations of the world. In large number of cases, acute traumatic perforations heal spontaneously, and in the healing process, stem cells appear to play an important role. However, no studies have been reported regarding somatic stem cells in the tympanic membrane. Herein, we tried to show that guinea pig's tympanic membrane contains cells that display the characteristic features of stem cells. MATERIALS AND METHOD: The tympanic membrane was obtained from the guinea pig. The cells were cultured in a medium with epidermal growth factor (EGF) and fibroblast growth factor (FGF). Proliferating cells were checked with stem cell markers, bromodeoxyuridine (BrdU) and nestin. Differentiated cells from stem cells are checked with betaIII tubulin and S-100. RESULTS: We observed that some of the cultured cells from the tympanic membrane were stained with both stem cell markers, BrdU and nestin. And we observed that these cells differentiated into neuron and gilal cells, which expressed betaIII tubulin and S-100, respectively. CONCLUSION: These results suggest that the tympanic membrane of guinea pigs may have neural stem cells. Further study is needed for finding the origin of stem cells.

Expression of Neural Cell Adhesion Molecule and Polysialic Acid in Cultured Spiral Ganglion Neurons / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Neural cell adhesion molecule (NCAM) and polysialic acid (PSA) function basically in cell adhesion and migration. In neural development, they are closely associated with axon pathfinding, synaptogenesis, neural cell migration, differentiation and myelination. The purpose of this study is to assess expression of NCAM and PSA expression in spiral ganglion neurons and Schwann cells and to postulate their functions. MATERIALS AND METHOD: Guinea pig spiral ganglion cells were harvested and cultured in vitro. The cells were grown and differentiated in culture medium together with brain derived neurotrophic factor (BDNF), neurotrophin 3 (NT-3) and glial cell derived neurotrophic factor (GDNF). After 1 week of culturing, the cells were fixed and immunocytochemical staining with beta-III tubulin, S-100, polysialic acid (PSA) and neural cell adhesion molecule (NCAM) were performed. We then checked axon growth rate with Axon Analyzer System(R). RESULTS: In the spiral ganglion culture, cultured neurons showed positive staining for beta-III tubulin, NCAM, and different expressions of PSA. S-100 positive glial cells (Schwann cells) showed different expressions of NCAM and no expression of PSA. Some NCAM positive neurons and Schwann cells were in contact each other. The growth rate of neuron was about 10-30 micrometer/h using Axon Analyzer System(R). CONCLUSION: We postulated that NCAM may play an important role in neural cell adhesion, myelination, fasciculation and ganglion formation. But PSA did not express the adhesive function of NCAM ; its absence may have been due to developmental reason. The differential expression of NCAM in the Schwann cells may indicate its different immunocytochemical characteristics and functions as shown in the CNS glial cells, astrocytes and oligodendrocytes.