Mimicking chronic glaucoma over 6 months with a single intracameral injection of dexamethasone/fibronectin-loaded PLGA microspheres

Abstract

To create a chronic glaucoma animal model by a single intracameral injection of biodegradable poly lactic-co-glycolic acid (PLGA) microspheres (Ms) co-loaded with dexamethasone and fibronectin (MsDexaFibro). MsDexaFibro were prepared by a water-in-oil-in-water emulsion method including dexamethasone in the organic phase and fibronectin in the inner aqueous phase. To create the chronic glaucoma model, an interventionist and longitudinal animal study was performed using forty-five Long Evans rats (4-week-old). Rats received a single intracameral injection of MsDexafibro suspension (10%w/v) in the right eye. Ophthalmological parameters such as clinical signs, intraocular pressure (IOP), neuro-retinal functionality by electroretinography (ERG), retinal structural analysis by optical coherence tomography (OCT), and histology were evaluated up to six months. According to the results obtained, the model proposed was able to induce IOP increasing in both eyes over the study, higher in the injected eyes up to 6 weeks (p < 0.05), while preserving the ocular surface. OCT quantified progressive neuro-retinal degeneration (mainly in the retinal nerve fiber layer) in both eyes but higher in the injected eye. Ganglion cell functionality decreased in injected eyes, thus smaller amplitudes in PhNR were detected by ERG. In conclusion, a new chronic glaucoma animal model was created by a single injection of MsDexaFibro very similar to open-angle glaucoma occurring in humans. This model would impact in different fields such as ophthalmology, allowing long period of study of this pathology; pharmacology, evaluating the neuroprotective activity of active compounds; and pharmaceutical technology, allowing the correct evaluation of the efficacy of long-term sustained ocular drug delivery systems.

Immune Analysis Using Vitreous Optical Coherence Tomography Imaging in Rats with Steroid-Induced Glaucoma

“…The dataset comprised images of the vitreoretinal interface obtained using OCT (HR-OCT Spectralis, Heidelberg ® Engineering, Heidelberg, Germany) in two previous interventional studies on the generation of steroid-induced glaucoma models (MsDx and MsDxF) [ 19 , 20 ], which detail the methodology followed. The experiment was previously approved by the Ethics Committee for Animal Research (PI34/17) of the University of Zaragoza (Spain) and was carried out in strict accordance with the Association for Research in Vision and Ophthalmology’s Statement on the Use of Animals.…”

“…The MsDx model was generated by injecting a 2-microlitre suspension (10% w) of biodegradable PLGA microspheres [ 23 ] loaded with dexamethasone into the anterior chamber of Long–Evans rats’ right eyes at 0 and 4 weeks [ 19 ]. The second model (MsDxF) was generated by administering a 2-microlitre suspension (10% w) of biodegradable PLGA microspheres co-loaded with dexamethasone and fibronectin at baseline in a single injection [ 20 ]. The left eyes did not undergo intervention.…”

“…This paper aims to corroborate the reliability of using computational OCT image analysis of hyperreflective opacities in the vitreous as a biomarker of vitreous immunity, in this case in two chronic steroid-induced glaucoma (SIG) rat models previously developed by our research group by injecting biodegradable microspheres (Ms) loaded with dexamethasone (MsDx) and a combination of dexamethasone and fibronectin (MsDxF) (with sustained release of the active compounds) into the anterior chamber of the eye [ 19 , 20 ]. Chronic exposure to glucocorticoids can raise IOP and is known to exert a negative effect in the form of maladaptive glial cell alterations and neuron damage or loss [ 21 ], leading to SIG [ 22 ].…”

Application of Biomedical Microspheres in Wound Healing

“…Among them, specific preparation method of W1/O/W2 emulsification is as follows: the drug is first dissolved in water, and then a polymer is dissolved in organic solvents, and then both are stirred at high speed and emulsify to form W1/O droplets, and W1/O droplets are finally placed in the external water phase (W2) containing an emulsifier to further emulsify to form W1/O/W2 droplets [ 33 ] ( Figure 3 b). The method is simple to operate and easy to control the parameters of process and does not require pH adjustment or temperature changes [ 44 ]. However, due to the poor lipophilicity of the encapsulated drugs, the microspheres generated with this method have drugs loading capacity (LC) as well as poor encapsulation efficiency (EE).…”

Evaluation of trabecular meshwork-specific promoters in vitro and in vivo using scAAV2 vectors expressing C3 transferase

“…This was likely caused by C3-induced RhoA inactivation which was accompanied by increased mRNA expression. Currently, classic pressure-dependent rat models generated by a series of methods, including intracameral injection of microbead [38][39][40] or viscous agent [41][42] , laser photocoagulation of outflow pathway [38,[43][44] , cautery of extraocular veins [45][46] , glucocorticoid induction [47][48] , transduction of the TM with glaucoma related genes [49][50][51] , or in combination with each other [52][53] , are widely used to understand the pathogenic mechanism of glaucoma, and regarded as relatively costefficient tools for developing potential glaucoma therapies. In this study, normal rats were used to evaluate initiation efficiencies of two TM-specific promoters in the scAAV2 vector.…”