Effects of Subretinal Injection of Patent Blue and Trypan Blue in Rabbits

Abstract

Purpose:: To investigate the histologic and clinical effects of subretinal injection of patent blue (PB) and trypan blue (TB) in rabbits

Methods:: Dutch-belted rabbits (n= 8) were vitrectomized followed by subretinal injection of 2.4 mg/ml PB (285 mOsm) and 1.5 mg/ml TB (312 mOsm); balanced salt solution (BSS) (300 mOsm) served as the control. Animals were examined 6, 12, and 24 hours and 14 days after the procedure by fluorescein angiography (FA) and indirect ophthalmoscopy; for retinal toxicity evaluation histologic studies were performed by light and transmission electron microscopy.

Results:: FA examination demonstrated window defects suggestive of RPE atrophy in positions of subretinal TB injection, but this was not observed following subretinal injection of PB or BSS. Histological evaluation disclosed only minimal abnormalities on the photoreceptor outer segment (POS) after subretinal injection of BSS during all follow-up. Subretinal injection of PB caused POS and photoreceptor inner segment (PIS) abnormalities 12 and 24 hours following surgery as well as outer nuclear layer (ONL) damage 14 days after surgery. Subretinal TB injection resulted in POS and PIS damage at 12 hours follow-up. The ONL damage was observed 24 h after surgery; additionally, POS, PIS, ONL and RPE abnormalities were observed 14 days following surgery after TB injection.

Conclusions:: Subretinal injection of TBinduced more significant clinical and histological damage of neurosensory retina/RPE than did PB or BSS. Future human studies are necessary to access the clinical relevance of these in vivo experiments.

Keywords: retina • photoreceptors • pathology: experimental