title: Experiment study of retinal ultrastructure after intravitreal FK506.
abstract: OBJECTIVE
  To investigate the retinal toxicity of FK506 by intravitreal administration.
  
  
  METHODS
  Twenty-two eyes of 14 New Zealand rabbits were investigated. FK506 at concentrations of 5,25 and 50 micrograms/eye was injected into the vitreous cavities respectively. The control eyes were received mixed solution of balanced salt and ethanol. All eyes were examined by tonometry, slit lamp and indirect ophthalmoscopy preoperatively and postoperatively at the 1st, 3rd, 7th, and 14th day respectively. In the final examination, all eyes were enucleated and processed for light and electron microscopy.
  
  
  RESULTS
  No evidence of toxic reaction was seen in the eyes received 25 micrograms FK506 or less of FK506. Several eyes received 50 micrograms FK506 and control eyes developed conjunctival congestion and slightly bloody exudates in anterior chamber which may be related to irritation of ethanol. Two of five eyes received 50 micrograms developed transient vitreous opacities. Electron microscopically, the mitochondria of the photoreceptor cells were swelled in the eyes treated with 50 micrograms FK 506.
  
  
  CONCLUSIONS
  It is safety with intravitreal FK506. There are no irritation and toxicity to the rabbits eyes with the intravitreal doses of 25 micrograms FK506 or less. The doses of 50 micrograms FK506 are proved to be toxic to the retina.
authors.affiliation: Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China.
authors.forename: Shuangnong
authors.initials: S
authors.lastname: Li
authors.forename: Shibo
authors.initials: S
authors.lastname: Tang
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Dongping
authors.initials: D
authors.lastname: Li
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D007166:Immunosuppressive Agents / Q000633:toxicity*; D007267:Injections; D011817:Rabbits; D012160:Retina / Q000648:ultrastructure*; D016559:Tacrolimus / Q000633:toxicity*; D014822:Vitreous Body
chemical_list: D007166:Immunosuppressive Agents; D016559:Tacrolimus