Abstract
Purpose::
To isolate and characterize progenitor cells derived from adult mammalian ciliary body.
Methods::
Progenitor cells were isolated from the ciliary body of adult mice, rats, and human cadaver eyes by modifications of methods reported by Tropepe et al. The immunolabeling and ultrastructure of NS cells were investigated by confocal and transmission electron microscopy.
Results::
We have previously determined quantitative growth characteristics of groups of progenitor cells called neurospheres (NS), including individual cell diameter, NS diameter, percentage of NS-forming cells and cell number per eye in mouse, rat and human eyes. In present study, we found that 87.1 ± 5.5% of NS cells expressed nestin, a molecule considered characteristic of progenitor and stem cells. Many NS cells also expressed Chx10 and Pax 6. In addition, 83.5 ± 8% of NS cells labeled positively for vimentin, 82.9 ± 7.4 % expressed Thy-1 and 97.4± 1 % were positive for GFAP. We did not detect labeling for calbindin, opsin and Brn3b, molecules characteristic of mature horizontal cells, rods, and retinal ganglion cells, respectively. Ultrastructurally, NS cells displayed abundant rough endoplasmic reticulum and many cellular processes, but no characteristics of mature retinal neurons or glia.
Conclusions::
Progenitor cells from adult mammalian ciliary body have significant, but limited proliferation potential and express markers characteristic of other progenitor cells, as well as those seen during early retinal development. The ciliary body could be a source of cells for transplant into experimental rodent and auto-transplant in human eyes.
Keywords: ganglion cells • immunohistochemistry • regeneration