Distribution of telocytes in the choroid (eye) of a teleost: An ultrastructural observation

This paper reports the presence of telocytes in the choroid, a pigmented vascular tissue layer of the eye, as examined by scanning and transmission electron microscopy. These cells are reported to occur in the stroma of heart, reproductive tissues, digestive tract, skin, lungs and excretory organs. In the choroid of the teleost Clarius gariepinus, telocytes are widespread over the entire area of the choroidal stroma. Their processes, called telopodes, are rather thin (<0.2 µm in diameter) and exceptionally longer (>50 µm), which branch into 3-5 short processes. These processes are intimately associated with the stromal collagen, melanocytes, and blood vessel walls. They formed homotypic contacts with adjacent telocytes, and heterocellular contacts with fibroblasts, mast cells, lymphocytes, macrophages and iridophores. Most cellular features were common in the choroidal telocytes that were described elsewhere in other organs of mammals. This study recognizes that telocytes are a regular cellular component of the choroid, and their intimate relationship with the stromal cells raises the possibility that they might play some hitherto unknown functions for those cells.