Looking for the Most Suitable Orthotopic Retinoblastoma Mouse Model in Order to Characterize the Tumoral Development.

Purpose: Because retinoblastoma therapies have many adverse effects, new approaches must be developed and evaluated on animal models. We describe orthotopic xenograft models of retinoblastoma using different strains of mice, suitable for this purpose.

Methods: Human retinoblastoma tumors were established on immunodeficient mice by subcutaneous engraftment of tumors from enucleated eyes. The orthotopic model was obtained by subretinal injections of suspension cells into the right eye of immunodeficient (Swiss-nude, severe combined immunodeficiency [SCID]) and immunocompetent mice (C57BL/6N, B6Albino). In vivo tumor growth was monitored by fundus and spectral-domain optical coherence tomography (SD-OCT) imaging and compared with histology.

Results: Retinal and vitreal tumor growth was achieved both in immunocompetent and immunodeficient strains after the subretinal injection of tumor cells. The best tumor engraftment rate was obtained in the SCID mice (68.8%). No tumor growth was observed in the C57BL/6N strain. Chronic retinal detachment may occur in most strains after the subretinal injection, in particular the Swiss-nude strain, which exhibits retinal degeneration.

Conclusions: The setting up of an orthotopic mouse model depends mainly on the choice of the engrafted cells (cell lines or patient-derived xenografts) but it can also depend on the xenografted mouse strain. Severe combined immunodeficiency mice (an immunodeficient strain) achieved the best tumor engraftment rate (68.8%). However, intraocular tumor growth was also satisfactory (50%) in the immunocompetent strain B6Albino, and this strain will allow to exploit the immune response after a tumor treatment. Both of these strains may therefore be recommended when setting up orthotopic retinoblastoma xenografts.