Objective To observe the morphological characteristics of photoreceptor necroptosis in experimental retinal detachment,and explore the mechanism.Methods A total of 60 Sprague-Dawley male rats were included in this study.Retinal detachment were induced in the right eyes with 1% sodium hyaluronate (50 μl) injection (experimental group),while the left eyes received no treatment (control group).At 3 days after modeling,the morphological characteristics of photoreceptor cell were observed by electron microscopy.Cleaved Caspase 8 and phosphorylation receptor-interacting protein 1 (p-RIP1) were measured by Western blot and immunoprecipitation.Results At 3 days after modeling,photoreceptor necroptosis showed the following morphological features:chromatin condensation,severe vacuolation,early loss of plasma membrane integrity,and many autophagosomes.Western blot showed that the protein expression of cleaved Caspase 8 were 0.78 ± 0.03,0.06 ± 0.01 in experimental group and control group respectively,which was significantly different (F=4 023.21,P<0.05).Immunoprecipitation showed that the protein expression of p-RIP1 were 0.23±0.03,0.14±0.02 in experimental group and control group respectively,which was significantly different (F =56.44,P < 0.05).Conclusions Photoreceptor necroptosis showed chromatin condensation,severe vacuolation,early loss of plasma membrane integrity,and many autophagosomes.Necroptosis activation was associated with the increase of RIP1 phosphorylation. Key words: Retinal detachment/physiopathology; Photoreceptor cells; Apoptosis; Animal experimentation