Because there are no reports on ET-1 and its effect in RP animal models, this study was designed to investigate the pattern of plasma ET-1 in rd10 mice, a typical RP model with a nonsense mutation of the pde6β gene, using bosentan, a dual endothelin receptor antagonist, to determine whether ET-1 blockade could slow down the progression of RP by regulating choroidal microvascular morphology in this model. The gene discussed is PDE6B; the disease is retinitis pigmentosa 1.