Preclinical investigation of the retinal biocompatibility of six novel vital dyes for chromovitrectomy.
OBJECTIVE
To investigate the retinal biocompatibility of six novel vital dyes for chromovitrectomy.


METHODS
An amount of 0.05 mL of 0.5% and 0.05% light green (LG), fast green (FG), Evans blue (EB), brilliant blue (BriB), bromophenol blue (BroB), or indigo carmine (IC) was injected intravitreally in the right eye, whereas in the left eye balanced salt solution was applied for control in rabbits' eyes. Clinical examination, fluorescein angiography, histology with light microscopy, and transmission electron microscopy were performed after 1 and 7 days. Retinal cell layers were evaluated for morphologic alterations and number of cells. The electroretinographic changes were assessed at baseline, 24 hours and 7 days.


RESULTS
Fluorescein angiography disclosed hypofluorescent spots only in the 0.5% EB group. Light microscopy and transmission electron microscopy disclosed slight focal morphologic changes in eyes exposed to 0.05% IC, FG, BriB, similar to the control at 1 and 7 days. In the lower dose groups, EB, LG, and BroB caused substantial retinal alterations by light microscopy. At the higher dose, BroB and EB produced diffuse cellular edema and vacuolization within the ganglion cells, bipolar cells, and photoreceptors. FG and IC at 0.5% caused slight retinal alterations similar to balanced salt solution injection. LG at 0.5% caused diffuse vacuolization of bipolar cells after 1 and 7 days. Injection of 0.5% EB caused a significant decrease in neuroretinal cell counts in comparison to control eyes in the 7-day examination (P < 0.05). Electroretinography revealed intermittent prolonged latency and decreased amplitude in eyes injected with 0.5% EB, LG, BriB, and BroB, while at the lower dose, only LG and EB induced few functional changes.


CONCLUSIONS
The progressive order of retinal biocompatibility, from safest to most toxic, was IC, FG, BriB, BroB, LG, EB.
Rodrigues
Eduardo B
EB
Department of Ophthalmology, Vision Institute (IPEPO), Federal University of São Paulo, Brazil. edubrodriguess@yahoo.com.br
Penha
Fernando Marcondes
FM
Farah
Michel Eid
ME
de Paula Fiod Costa
Elaine
E
Maia
Mauricio
M
Dib
Eduardo
E
Bottós
Juliana
J
Freymuller
Edna
E
Furlani
Bruno
B
Meyer
Carsten H
CH
Magalhães
Octaviano
O
Lima-Filho
Acácio Alves Souza
AA
Safatle
Angélica
A
D000818:Animals; D002452:Cell Count; D004396:Coloring Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000633:toxicity; D004305:Dose-Response Relationship, Drug; D004487:Edema / Q000139:chemically induced; D004596:Electroretinography; D005451:Fluorescein Angiography; D007267:Injections; D008297:Male; D008422:Materials Testing; D008854:Microscopy, Electron; D011817:Rabbits; D011930:Reaction Time / Q000187:drug effects; D012160:Retina / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology; D012164:Retinal Diseases / Q000139:chemically induced; D014617:Vacuoles / Q000473:pathology; D014821:Vitrectomy / Q000379:methods*; D014822:Vitreous Body
D004396:Coloring Agents