Congenital nuclear cataracts and uveitis in HIV-transgenic mice

Patients infected with HIV-1 develop ocular manifestations, some due to opportunistic infections and others attributed to the virus itself. Among the latter are retinal microvasculopathy and uveitis. We have analysed the ocular phenotype in HIV-transgenic mice.

We have studied T26 transgenic mice which bear a gag-pol deleted HIV-1 genome. Transgene RNA was detected by Northern analysis. Ocular pathology was assessed by conventional histology, immunostaining for gp120 envelope protein, and in situ apoptosis detection with end-labelling.

Abnormalities of lens epithelial cell development were detected as early as embryonic day 14.5. Histological changes included the malformation of an embryonal lens nucleus and poor closure of the lens suture lines. This resulted in congenital nuclear cataracts, as occur in congenital viral infections in human patients. In the adult animals, lenses were notable for extensive vacuolation, liquefaction, and degeneration of the cortex. Mild iridocyclitis and vitritis were also noted in adult transgenic mice. Immunostaining demonstrated the expression of gp 120 envelope protein within the lens epithelial and fibre cells. End-labelling with terminal deoxyribonucleotidyl transferase showed increased numbers of apoptotic cells in the adult lens.

These findings suggest that one or more HIV-1 proteins are associated with congenital nuclear cataract formation and uveitis in HIV-transgenic mice.