Tissue culture of XXXX ciliary body epithelial cells on permeable supports.

@entity7462 @entity95 @entity8038 @entity597
The @entity7462 is produced by the epithelium of the ciliary body, a complex structure encircling the anterior segment of the eye. @entity7462 production occurs by active transport, but the mechanism of this process is not understood. To produce a preparation in which active transport can be investigated, we have attempted to prepare cultures suitable for measurements of ion and water flux. We have grown @entity95 ciliary body epithelial cells on permeable supports, coated with several extracellular matrix proteins. We then examined the ability of these proteins to promote the growth of a differentiated layer of epithelial cells. Non-pigmented and pigmented cells formed sheets of contiguous cells when grown on a variety of support media. The most successful substrate was a permeable support produced by @entity8038 with a mixture of collagen IV, laminin and heparan @entity597 . Under these conditions, cultures could be maintained for several months, but pigmented cell cultures did not develop a measurable transepithelial resistance (TER), and the TER of non-pigmented cell cultures was typically only 20-30 omega cm2. Much higher TERs exceeding 200 omega cm2 could be measured from non-pigmented cell cultures 3-5 days after plating, but these high values were unstable. Examination of the cultures with electron microscopy revealed that the cells were partially differentiated with the formation of a basal lamina and intercellular junctions. Labelling with a specific monoclonal antibody marker for tight junction protein (ZO-1) suggested that non-pigmented cell cultures showed extensive tight junction formation. The low TER of the non-pigmented cell cultures appears therefore not to be due to the lack of tight junctions but rather to the presence of spaces between cells.
