chronic glaucoma in rats induced by single injection of fibronectin‐loaded PLGA microspheres

Purpose: To generate a model of chronic glaucoma in rats, by means of a single injection that simulates the pathology that occurs in humans. Methods: A total of 47 Long‐Evans rats of both sexes were used; 30 rats received an intracameral injection of a suspension of fibronectin‐loaded poly‐lactic‐glycolic acid microspheres into the right eye, and the other 17 served as controls. They were followed up for 24 weeks, evaluating intraocular pressure (IOP) with a rebound tonometer, neuro‐retinal structure by optical coherence tomography (OCT) with segmentation protocols for the analysis of the entire retina, the ganglion cell layer (GCL) and the peripapillary retinal nerve fibre layer (pRNFL); as well as retinal functionality by electroretinography (ERG). Results: The IOP of the induced eyes increased progressively and chronically (11.64 ± 1.43 to 21.89 ± 3.94 mmHg) compared to the controls ( p = 0.025) and with higher levels than the contralateral eyes ( p < 0.05) until week 20, when this trend reversed. The induced eyes showed fluctuations in OCT retinal thickness over time. A trend of less thickness in the retina and GCL was measured in the induced eye and its contralateral eye; but at the end of the study, greater thicknesses were quantified than in the control eyes ( p = 0.036). In addition, a lower ERG signal was recorded in the induced eyes. Ganglion cell functionality progressively decreased and was lower than contralateral eyes and control eyes at 12 and 24 weeks ( p < 0.05). Males showed higher IOP ( p < 0.05), greater thicknesses in the retina and lesser in the GCL and pRNFL ( p < 0.05), with decreased functionality at 12 and 24 weeks compared to females. Conclusions: A minimally invasive chronic glaucoma model was obtained using single‐injection by pharmaceutical technology, which produced a progressive increase in intraocular pressure and structural and functional neuro‐retinal damage.