Light Scattering and Morphology of Cataract Formation in Transgenic Mice Containing the HIV-1 Protease Linked to the Lens αA-Crystallin Promoter

Two constructs of transgenic mice, TG61and TG72, containing the HIV-1 protease linked to the lens αA-crystallin promoter develop cataract. The TG61construct develop cataract in utero, while the TG72construct exhibit frank opacities on the 24th day (homozygotes) and 26th day (hemizygotes) post natum. Polarized light scattering measurements were performed on cortical and nuclear sections of TG72lenses from day 19 to day 26 as a function of scattering angle. The parallel components of the scattered light intensity increase gradually during opacification, the perpendicular components show very low values from day 19 to day 22 after which they increase exponentially. Analysis of the scattered light intensities yielded parameters describing the size of the protein aggregates, the size of the domains exhibiting optical anisotropy/birefringence, the difference in refractive index between (a) the protein aggregates and their surroundings and (b) the birefringent units and their surroundings. The last parameter accounts for the major portion of the increase in lens turbidity.