Interactions of extracellular collagen and corneal fibroblasts: Morphologic and biochemical changes of rabbit corneal cells cultured in a collagen matrix

Abstract

Corneal fibroblasts, also known as keratocytes are surrounded by an extracellular matrix of collagen in vivo. To understand the physiology and pathology of these corneal fibroblasts, it is important to study their interactions with this extracellular matrix. We cultured rabbit corneal fibroblasts on tissue culture plastic dishes or in a hydrated collagen gel and compared the changes in morphology and mitotic activity. Corneal fibroblasts on plastic dishes were flattened and widely spread, whereas those in collagen gel became spindle-shaped with long processes. Examination with an electron microscope revealed that the corneal fibroblasts in collagen gel formed gap junctions with neighboring cells. Gap junctions were hardly ever observed between corneal fibroblasts cultured on plastic dishes. Corneal fibroblasts cultured in a collagen matrix showed much less incorporation of [3H]thymidine than did corneal fibroblasts cultured on plastic, and this incorporation decreased with increasing concentration of collagen. Our present results suggest that the morphologic and biochemical characteristics of corneal fibroblasts cultured in collagen gel are different from those cultured on plastic.

Galardin Inhibits Collagen Degradation by Rabbit Keratocytes by Inhibiting the Activation of Pro-Matrix Metalloproteinases

“…In the corneal stroma, keratocytes are embedded in extracellular matrix proteins, mainly type I collagen ; the cells' functions are continuously modulated by interaction with this extracellular matrix. Thus, threedimensional culture of keratocytes in collagen gel represents the conditions more closely related to the situation in vivo than does monolayer culture (Ueda et al, 1987 ;Nishida et al, 1988). The present study used this model to examine the inhibitory action of Galardin on collagen degradation by keratocytes.…”

Extracellular Collagen Promotes Interleukin-1β–Induced Urokinase-Type Plasminogen Activator Production by Human Corneal Fibroblasts

“…addition, our previous 4 and present results show that the morphology of corneal fibroblasts embedded in such a gel resembles that of corneal fibroblasts in vivo, suggesting that three-dimensional culture of the cells in a collagen matrix more closely reflects the in vivo situation than does their twodimensional culture on plastic.…”

“…4 In FIGURE 8. Inhibition of the stimulatory effect of IL-1b on uPA expression in corneal fibroblasts by knockdown of IL-1R.…”

“…4 In brief, type I collagen (Nitta Gelatin) was mixed with 103 MEM and neutralized with 0.2 M NaOH before the addition of corneal fibroblasts to a final density of 1 3 10 5 cells/mL and final collagen concentration of 2 mg/mL (unless indicated otherwise). A portion (300 lL) of the cell suspension was transferred to the wells of a 24-well tissue culture plate, which was then incubated at 378C for 1 hour to allow gel formation.…”

“…3 Under normal conditions and during wound healing, extracellular collagen not only maintains corneal stromal morphology but is also thought to regulate the structure and function of keratocytes. The shape of the corneal stromal cells in vitro has thus been found to be affected by the presence of an extracellular collagen matrix, 4 whereas collagen has been shown to regulate cell movement and migration, cytoskeletal organization, and cell proliferation in other cell types. [5][6][7] A proteolytic cascade including urokinase-type plasminogen activator (uPA), plasmin, and matrix metalloproteinases (MMPs) plays a key role in the degradation of collagen fibrils.…”