Vehicle Used for Triamcinolone Acetonide is Toxic to Ocular Tissues of the Pigmented Rabbit

Abstract

Purpose: To investigate the potential toxicity of the vehicle used for triamcinolone acetonide (TA) to the cornea, lens, ciliary body, and retina of pigmented rabbits. Methods: Forty chinchilla rabbits (40 eyes) were divided into four groups: group A (control group) eyes received an intravitreal injection of 0.1 ml sterile saline solution; group B eyes received 0.1 ml (1.3 mg) TA plus vehicle; group C eyes received 0.1 ml (1.3 mg) TA alone (vehicle eliminated); group D eyes received 0.1 ml vehicle only. Intraocular pressure (IOP) was measured pre-injection and at 1, 7, 14, 30, and 90 days post-injection. Scotopic and photopic electroretinograms (ERG) were examined pre-injection and 7, 30, and 90 days post-injection. Animals were sacrificed 7, 30, and 90 days post-injection. Eyes were enucleated and examined by light microscopy (LM) and electron microscopy (EM). Results: The IOP of groups B and C was higher than that of other groups on days 1, 7, and 14 post-injection (p < 0.05). ERG amplitudes of groups B and D were lower than those of other groups on days 7 and 30 post-injection (p < 0.05). Histopathological sections indicated morphologic changes in the ciliary body, lens, and retina of eyes in groups B and D. Conclusions: Vehicle used for TA is toxic to the lens, ciliary body, and retina of pigmented rabbit eyes after injection of intravitreal TA.