Disease Course And Lipid Metabolism Research Of Cyp4v3^-/- Mice Model Of Bietti Crystalline Dystrophy

Purposes:To identify the phenotype of Cyp4v3-/-mice model of Bietti crystalline dystrophy,observe the natural disease course of this mice model and analyze the blood metabolomics.To explore the possible mechanism affecting the occurrence and development of disease and to evaluate whether this mouse model can be used as a suitable preclinical treatment research model.Methods:Cyp4v3-/-mice were constructed by CRISPR/Cas9 gene editing technology,and were massively propagated.First,the protein expression was identified by immunofluorescence of retina.Cyp4v3-/-mice of Bietti crystalline dystrophy were divided into two groups,one group was fed with a high-fat diet,and the other group was fed with a normal diet.C57BL/6J mice were used as normal control.Fundus photography,optical coherence tomography(OCT),fundus autofluorescence and electroretinogram(ERG)were performed in three groups of mice every 4 weeks until week 20.In addition,C57BL/6J mice were fed with high fat for 8 weeks,and their fundus and ERG were examined.Cyp4v3-/-mice and wild-type mice of the same age were sacrificed,and their eyeballs were removed for retinal sections,HE staining and transmission electron microscopy.To collect blood samples from Cyp4v3-/-mice and wild-type mice,and untargeted lipid profiling was performed with Ultra-performance liquid chromatography-mass spectrometry(UPLC-MS).Results:Retinal immunofluorescence of retina showed no Cyp4v3 protein expression in the mice model.Compared with wild type mice,fundus of Cyp4v3-/-mice model of Bietti crystalline dystrophy appeared yellow large lesions with a variety of shapes.High signal reflection material depositions can be seen in the outer retina from OCT,mottled high fluorescence signal can be seen at the fundus lesions from autofluorescence,and ERG showed a gradual decline in the process and HE staining showed a thin retina.Transmission electron microscopy(TEM)showed the photoreceptor was sparse and disorderly,and some materials were secreted from the photoreceptor.In addition,Cyp4v3-/-mice fed with high-fat diets showed earlier onset of fundus lesions with larger and more severe lesions,more significant ERG decline,and thinner retinal thickness than mice fed with normal diets.The wild-type mice fed with high fat showed normal fundus and retinal function.Lipid metabolism analysis showed that more than ten kinds of lipid compounds in the mouse model were different from the normal control.Conclusions:The fundus of Cyp4v3-/-mice of Bietti crystalline dystrophy have characteristic changes,decreased retinal function and abnormal lipid metabolism,which are similar to human patients.In addition,high-fat feeding can accelerate and aggravate the appearance of the phenotype of disease,and this mice model can be used as a promising model for treatment research.