Apoptosis regulated by growth factors in multicellular spheroids of trabecular cells

Bovine and porcine trabecular cells were incubated up to one month in a polystyrene dish nonadherent environment for suspension culture, and their morphological changes were examined by light and electron microscopy. The trabecular cells formed multicellular spheroids during the first day. Apoptosis occurred selectively and continuously in the spheroids, which had initially been filled with cells. After one month, the final structure of the spheroids had become a meshwork of cells separated by large extracellular spaces. Epidermal and basic fibroblast growth factors prevented apoptosis of the trabecular cells in the spheroids which remained filled with cells for the entire observation period. The trabecular multicellular spheroids may represent the in vivo process of trabecular meshwork formation and can be used as a system for identifying regulatory factors involved in this process.