Purpose: Uveal melanoma (UM) is the most common malignant intraocular malignancy in adults, leading to visual loss and even death when metastasizes to main organs. Recent treatment modalities have been developed to prevent enucleation-related vision loss and death. Having a proper animal model for intraocular melanoma is necessitated to examine the efficacy of new treatment strategies. This study was conducted to develop a rabbit model of intraocular melanoma.

Methods: Eight-month old New Zealand white rabbits were inoculated with 3 X 106 cultivated human UM cells per 0.1ml FBS following a 5-day immunosuppression with oral cyclosporine. Either trans-scleral or intravitreal approaches were used and the inoculated eyes were examined weekly for any evidence of intraocular tumor formation. Oral cyclosporine was continued for 4 weeks when the rabbits were euthanized and the inoculated eyes were enucleated. Routine histology and immunohistochemistry for melan A were then performed.

Results: Trans-scleral, intravitreal, and a combination of trans-scleral and intravitreal approaches were used in 3, 3, and 1 rabbits respectively. Clinical examinations revealed no evidence of intraocular tumor in any of the inoculated eyes. Light microscopy disclosed either episcleral micronodules or intravitreal sheaths of tumor cells in 3 of 3 intravitral cases, 1 of 3 trans-scleral cases and 1 of 1 combined case.

Conclusion: It seems that intravitreal injection of cultivated human UM cells, is more feasible and effective than trans-scleral approach for development of UM animal model. To our best knowledge, this study was the first experience to induce an animal model of intraocular melanoma in Iran. Further study with longer follow-up and using small rodents with more effective immunosuppression is suggested to obtain a gross intraocular melanoma.