title: Proteomic analysis of retinal proteins in rabbits following intravitreal PBS injection: analysis with tandem mass tag labeling coupled with LC-MS/MS.
abstract: OBJECTIVE
  Intravitreal (IVT) injection has become one of the most commonly performed ophthalmologic procedures. We investigated the changes in retinal function and proteomics in rabbits receiving IVT injection of PBS to evaluate the safety of IVT injection.
  
  
  METHODS
  Twenty Chinchilla rabbits were subjected to IVT injection of 50 µL PBS in the right eyes. On days 0, 4, 7 and day 14, the retinas of the rabbits were isolated after routine ophthalmic and electroretinogram examinations. The protein expressions in the retinas were quantified using tandem mass tag (TMT)-labeling coupled with LC-MS/MS, and bioinformatic analysis of the differentially expressed proteins (DEPs) was performed based on KEGG database to identify significantly enriched pathways. Functional network of the significant DEPs was analyzed using STRING.
  
  
  RESULTS
  No noticeable fundus or functional changes occurred in the rabbit eyes following IVT injection of PBS. A total of 6042 retinal proteins were identified in the retina following the injection, among which 49 proteins (0.81%) exhibited over 5.0-fold up-regulation or over 80% down- regulation relative to the control. Most of the distinctly up-regulated or down-regulated proteins were associated with the cytoskeleton. Significantly enriched pathways involved focal adhesion, tight junction, riboflavin metabolism, extracellular matrix-receptor interaction and regulation of actin cytoskeleton. Functional network analysis showed that ACTC1 and ISG15 played central roles in the protein interaction networks.
  
  
  CONCLUSIONS
  IVT PBS injection in rabbits causes alterations in proteins associated with cell adhesion, morphology, migration, differentiation, signal transduction and riboflavin metabolism, but the alterations of the retinal proteins appear not sufficient to cause observable pathology of the retina.
authors.affiliation: Department of Ophthalmology, the First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing 400016, China.E-mail: 38584586@qq.com.
authors.forename: Jia-Ming
authors.initials: JM
authors.lastname: Wang
authors.forename: Bo
authors.initials: B
authors.lastname: Lei
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid; D004596:Electroretinography; D005136:Eye Proteins / Q000378:metabolism*; D058449:Intravitreal Injections; D020543:Proteome / Q000378:metabolism*; D040901:Proteomics; D011817:Rabbits; D012160:Retina / Q000378:metabolism*; D053719:Tandem Mass Spectrometry
chemical_list: D005136:Eye Proteins; D020543:Proteome