In vitro growth and collagen synthesis in fibroblasts from the rabbit middle ear mucosa

The present methodological study was undertaken to introduce a model system in which individual cells of the middle ear mucosa could be studied under controlled conditions allowing standardized sampling and different manipulations using quantitative methods. The method is based upon isolation and culture of fibroblasts from normal rabbit middle ear mucosae. The growth pattern of the cells was determined by measurement of the total content of cell protein, DNA content and cell division activity. Collagen synthesis was also estimated and results compared with normal skin fibroblasts. Finally, fibroblasts derived from rabbit middle ear mucosae with otitis media were cultured under similar conditions. Results demonstrated the method to be valid and reproducible. Evaluated by any of the parameters applied, growth initially increased exponentially, followed by a stationary phase with a constant cell mass. The growth potentials in middle ear fibroblasts appeared to differ significantly from skin fibroblasts. Except for a decreased cell proliferation, fibroblasts from diseased mucosae did not demonstrate any major differences from the normal fibroblasts probably because the original inflammatory stimuli in vivo were lost in vitro. These findings suggest that future investigations of a model system of otitis media in vitro require the addition of inflammatory mediators.