Lens epithelial cells attached to the anterior capsules of patients with nuclear or anterior polar cataracts were analyzed quantitatively for α-crystallin proteins and mRNAs using Western blot and RT-PCR analysis., respectively. The degree of modification of α-crystallins was determined by 2-dimensional gel electrophoresis followed by Western blotting.

Higher molecular weight protein bands that were immunoreactive to anti-αA- and anti-αB-crystallin antibodies around 45 kDa accumulated more in the anterior polar cataract samples than in those with the nuclear type of cataracts. Also monomeric αB-crystallins accumulated more in lens epithelial cells of patients with anterior polar cataracts. By comparison, no significant changes were found in the levels of the mRNAs encoding αA- and αB-crystallins in the different types of cataracts. Both αA- and αB-crystallin proteins seemed to undergo more extensive modification in anterior polar cataracts.

Conclusion. In addition to fibrotic changes, which accompany increased levels of extracellular matrix molecules, accumulation and abnormal modification of α-crystallins might be implicated in the pathogenic mechanism of this type of cataract.