Purpose: To evaluate the potential of gene therapy with a recombinant adeno-associated virus vector encoding the interleukin-1 receptor antagonist gene (rAAV-IL-1Ra) in the treatment of experimental uveitis.
Methods: The vitreal cavity of New Zealand white rabbits was injected with rAAV-IL-1Ra (4x10(7) infectious units), and the contralateral eye was injected with the same amount of rAAV-LacZ or PBS as a control. Transgene expression was evaluated by immunohistochemistry, ELISA, and RT-PCR. To evaluate the therapeutic potential of rAAV-IL-1Ra, experimental uveitis was induced by intravitreal injection of IL-1alpha at 10 and 100 days after rAAV-IL-1Ra administration. The effects of rAAV-IL-1Ra on experimental uveitis were investigated using histological and aqueous analysis.
Results: Following intravitreal injection of rAAV-IL-1Ra, transgene expression was found in various cell types of the ocular tissues, such as ciliary epithelial cells, retinal ganglion cells, and retinal pigment epithelial cells. RT-PCR and ELISA showed that the IL-1Ra transgene persisted in the rabbit eye for at least 100 days. Compared with the control eyes, the transgene expression ameliorated experimental uveitis at 10 and 100 days after a single administration of rAAV-IL-1Ra.
Conclusions: Intravitreal administration of rAAV-IL-1Ra led to sustained human IL-1Ra transgene expression in rabbit eyes for 100 days. The transgene expression suppressed uveitis episodes at 10 and 100 days after rAAV-IL-1Ra injection. Long-term suppression of experimental uveitis could be achieved by gene therapy with rAAV-IL-1Ra.