Abstract
Purpose: :
Evaluation of the efficacy of a chorioretinitis model induced by subretinal injection of lipopolysaccharide(LPS) or M. butyricum suspension.
Methods: :
New Zealand White rabbits(n=17) were randomly assigned to a control group challenged by a subretinal injection of hyaluronic acid(HA), one group challenged by subretinal injection of Escherichia coli 0113:H10 LPS in HA with a final concentration of 0.8 mg/ml and 400 ug/g of LPS with respect to HA, and three experimental groups challenged by subretinal injection of M. butyricum suspended in HA for a final concentration of 1.0 mg/ml, and sensitized by subcutaneous injection as follows: 1) rabbit receiving two 0.25 ml antigen/IFA, 2) rabbit receiving two 0.5 ml antigen/IFA, and 3) non-sensitized rabbits. Sham and LPS subretinal injection rabbits were challenged on Day 1; heat-killed M. butyricum rabbits were sensitized on Day 1, and challenged on Day 4. Subretinal injection consisted of ~ 20 µl of LPS, M. butyricum or sham suspension adjacent to optic nerve. Ophthalmic examination, color fundus photography and fluorescein angiography (FA) were evaluated over 30-days. Eyes were evaluated histopathologically.
Results: :
Sham group demonstrated no evidence of chorioretinitis. Group challenged with LPS suspension showed acute panuveitis (Day 2); clinical findings consisted of moderate-to-severe cellular/aqueous flare in the anterior chamber initially. Severe cellular response of the posterior chamber progressed to mildly involve the anterior vitreous accompanied by a snow ball like formation in the inferior vitreous (up to 10 days) making the subretinal injection difficult to visualize. FA findings correlated with ophthalmic findings of moderate-to-severe choroid/retina inflammation and retinal vasculitis. All groups (sensitized or not) challenged by M. butyricum suspension demonstrated prolonged period (~30 days) of chorioretinitis with minimal involvement of the anterior chamber. Ocular exams and fundus photography revealed mild-to-moderate choroid/retinal inflammation, retinal hemorrhage and vitreal opacities. FA demonstrated vasculature leakage. Histopathology indicated granulomatous inflammation in LPS and M. butyricum groups.
Conclusions: :
Subretinal injection of LPS provides an acute model of chorioretinitis with initial anterior chamber involvement. Subretinal injection of M. butyricum is a good model for prolonged chorioretinitis with minimal involvement of the anterior chamber.
Keywords: uveitis-clinical/animal model • chorioretinitis • retinitis