The effects of fibroblast growth factors 1 and 2 on fibre growth of wool follicles in culture.

The effects of fibroblast growth factor-1 (FGF-1) and FGF-2 on fibre growth and follicle function were examined using a previously described procedure to culture wool follicles. Because the FGFs bind to glycosaminoglycan components of the extra-cellular matrix, we also investigated interactions between FGF-1 and FGF-2 with heparin on wool fibre growth. Individual follicles were microdissected from Merino sheepskin and transferred to culture. Follicles increased in length for 6 days, and in all groups, no significant differences in follicle length were observed. Increase in follicle length was associated with fibre growth, follicles maintained normal anagen morphology and incorporated [3H]thymidine into the bulb and outer root sheath cells. Follicles in all treatments continued to produce fibre keratins, as detected by immunohistochemistry. However, the patterns of fibre and cytoskeletal proteins incorporating [35S]methionine in control and treated follicles were significantly different. We found a considerable decrease in the intermediate filament keratins or low sulphur proteins in follicles cultured in the presence of FGF-1 and FGF-2 compared to controls. The majority of proteins detected in these samples were acidic high sulphur proteins. These studies provide evidence for a specific role for the fibroblast growth factors in the regulation of fibre differentiation.