THE EFFECTS OF FIBROBLAST GROWTH-FACTOR-1 AND GROWTH-FACTOR-2 ON FIBER GROWTH OF WOOL FOLLICLES IN CULTURE

The effects of fibroblast growth factor-1 (FGF-1) and FGF-2 on fibre g rowth and follicle function were examined using a previously described procedure to culture wool follicles, Because the FGFs bind to glycosa minoglycan components of the extra-cellular matrix, we also investigat ed interactions between FGF-1 and FGF-2 with heparin on wool fibre gro wth. Individual follicles were microdissected from Merino sheepskin an d transferred to culture. Follicles increased in length for 6 days, an d in all groups, no significant differences in follicle length were ob served. Increase in follicle length was associated with fibre growth, follicles maintained normal anagen morphology and incorporated [H-3]th ymidine into the bulb and outer root sheath cells. Follicles in all tr eatments continued to produce fibre keratins, as detected by immunohis tochemistry. However, the patterns of fibre and cytoskeletal proteins incorporating [S-35]methionine in control and treated follicles were s ignificantly different. We found a considerable decrease in the interm ediate filament keratins or low sulphur proteins in follicles cultured in the presence of PGF-1 and FGF-2 compared to controls. The majority of proteins detected in these samples were acidic high sulphur protei ns. These studies provide evidence for a specific role for the fibrobl ast growth factors in the regulation of fibre differentiation.