LOCALIZATION OF ACIDIC FIBROBLAST GROWTH-FACTOR, BASIC FIBROBLAST GROWTH-FACTOR, AND HEPARAN-SULFATE PROTEOGLYCAN IN RAT LENS - IMPLICATIONS FOR LENS POLARITY AND GROWTH-PATTERNS

Purpose. Previous research in this laboratory has shown that fibroblas t growth factor stimulates lens epithelial explants to proliferate, mi grate, and differentiate into fibers in a progressive dose-dependent m anner. The lens has distinct compartments where cells proliferate (ger minative zone), migrate, or get displaced (equator) and differentiate into fibers (transitional zone). These compartments occur in an antero posterior spatial sequence and the authors hypothesized that fibroblas t growth factor plays a critical role in determining these spatial pat terns of lens growth and lens polarity. To investigate this hypothesis the distribution of fibroblast growth factor in the lens was analyzed . Methods. Immunohistochemistry was used to localize acidic fibroblast growth factor and basic fibroblast growth factor in the cells and cap sule of lenses from neonatal, weanling, and adult rats. Because of its functional relationship with fibroblast growth factor, heparan sulpha te proteoglycan was also localized in the lens. Results. In all ages e xamined, cytoplasmic acidic fibroblast growth factor is present in the germinative and transitional zones of the lens and both acidic fibrob last growth factor and basic fibroblast growth factor are present in t he capsule. A major finding is the co-localization of fibroblast growt h factor and heparan sulphate proteoglycan reactivity in the lens caps ule in the form of laminae. These laminae become more prominent as the capsule thickens and differences in arrangement of laminae between an terior, equatorial, and posterior regions of the capsule also become a pparent. Conclusions. The presence of fibroblast growth factor in lens cells and capsule in neonatal, weanling, and adult rats indicates an important role for fibroblast growth factor in lens cell biology. More over, the regional distribution of fibroblast growth factor, particula rly in the lens cells, indicates that it may influence determination o f lens polarity and growth patterns.