in-vivo-multimodal-imaging-analysis-mouse-laser-induced-choroidal

<em>In Vivo</em> Multimodal Imaging and Analysis of Mouse Laser-Induced Choroidal Neovascularization Model

Laser-induced choroidal neovascularization (CNV) is a well-established model to mimic the wet form of age-related macular degeneration (AMD). In this ...

oxygen-induced-retinopathy-model-for-ischemic-retinal-diseases

Oxygen-Induced Retinopathy Model for Ischemic Retinal Diseases in Rodents

One of the commonly used models for ischemic retinopathies is the oxygen-induced retinopathy (OIR) model. Here we describe detailed protocols for the OIR ...

Experimentica Ltd.

Experimentica Ltd

Huntington's disease (HD) is an inherited neurodegenerative disorder that primarily affects the medium-size GABAergic neurons of striatum. The R6/2 mouse line is one of the most widely used animal models of HD. Previously the hallmarks of HD-related pathology have been detected in photoreceptors and interneurons of R6/2 mouse retina. Here we aimed to explore the survival of retinal ganglion cells (RGCs) and functional integrity of distinct retinal cell populations in R6/2 mice. The pattern electroretinography (PERG) signal was lost at the age of 8 weeks in R6/2 mice in contrast to the situation in wild-type (WT) littermates. This defect may be attributable to a major reduction in photopic ERG responses in R6/2 mice which was more evident in b- than a-wave amplitudes. At the age of 4 weeks R6/2 mice had predominantly the soluble form of mutant huntingtin protein (mHtt) in the RGC layer cells, whereas the aggregated form of mHtt was found in the majority of those cells from the 12-week-old R6/2 mice and onwards. Retinal astrocytes did not contain mHtt deposits. The total numbers of RGC layer cells, retinal astrocytes as well as optic nerve axons did not differ between 18-week-old R6/2 mice and their WT controls. Our data indicate that mHtt deposition does not cause RGC degeneration or retinal astrocyte loss in R6/2 mice even at a late stage of HD-related pathology. However, due to functional deficits in the rod- and cone-pathways, the R6/2 mice suffer progressive deficits in visual capabilities starting as early as 4 weeks; at 8 weeks there is severe impairment. This should be taken into account in any behavioral testing conducted in R6/2 mice. 

Early retinal function deficit without prominent morphological changes in the R6/2 mouse model of Huntington's disease.

The purpose of the study was to devise a fast, reliable and sensitive cell viability assay for assessment of acute cytotoxicity on human corneal epithelial cells by using a clinically relevant exposure time. Acute cytotoxic effects of the pharmaceutical excipients benzalkonium chloride (BAC), macrogolglycerol hydroxystearate (MGHS40), polysorbate 80 (PS80) and marketed ophthalmic formulations (Lumigan(®), Monoprost(®), Taflotan(®), Travatan(®), Xalatan(®)) containing these excipients were tested. Human corneal epithelial cell (HCE-T) viability was assessed by measuring the reduction of resazurin to highly fluorescent resorufin. Expression of the tight junction proteins in HCE-T cells were characterized by immunofluorescence staining. Presence of tight junction proteins in HCE-T cells was demonstrated. BAC preserved ophthalmic formulations showed concentration-dependent and time-dependent cytotoxicity to human corneal epithelium. In contrast, no acute cytotoxicity of non-ionic stabilizing/solubilizing excipients (MGSH40 and PS80) or ophthalmic formulation containing these excipients was observed. Marketed ophthalmic formulations used for glaucoma medication show differential toxicity on human corneal epithelial cells. The present study revealed that BAC-preserved ophthalmic formulations were able to induce acute cytotoxic effects even during a clinically relevant exposure time, which was not observed with MGSH40 and PS80 excipients or ophthalmic formulations containing these excipients.

Acute cytotoxic effects of marketed ophthalmic formulations on human corneal epithelial cells.

BACKGROUND In glaucoma, non-intraocular pressure (IOP)-related risk factors can result in increased levels of extracellular glutamate, which triggers a cascade of neurodegeneration characterized by the excessive activation of N-methyl-D-aspartate (NMDA). The purpose of our study was to evaluate the glioprotective effects of memantine as a prototypic uncompetitive NMDA blocker on retinal astrocytes in the optic nerve crush (ONC) mouse model for glaucoma. MATERIAL AND METHODS Optic nerve crush was performed on all of the right eyes (n=8), whereas left eyes served as contralateral healthy controls (n=8) in Balb/c/Sca mice. Four randomly assigned mice received 2-µl intravitreal injections of memantine (1 mg/ml) after ONC in the experimental eye. One week after the experiment, optic nerves were dissec-ted and stained with methylene blue. Retinae were detached from the sclera. The tissue was immunostained. Whole-mount retinae were investigated by fluorescent microscopy. Astrocyte counts for each image were performed manually. RESULTS Histological sections of crushed optic nerves showed consistently moderate tissue damage in experimental groups. The mean number of astrocytes per image in the ONC group was significantly lower than in the healthy control group (7.13±1.5 and 10.47±1.9, respectively). Loss of astrocytes in the memantine-treated group was significantly lower (8.83±2.2) than in the ONC group. Assessment of inter-observer reliability showed excellent agreement among observations in control, ONC, and memantine groups. CONCLUSIONS The ONC is an effective method for investigation of astrocytic changes in mouse retina. Intravitreally administered memantine shows a promising glioprotective effect on mouse retinal astrocytes by preserving astrocyte count after ONC.

Glioprotection of Retinal Astrocytes After Intravitreal Administration of Memantine in the Mouse Optic Nerve Crush Model.

The Finnish variant of late infantile neuronal ceroid lipofuscinosis (CLN5 disease) belongs to a family of neuronal ceroid lipofuscinosis (NCLs) diseases. Vision loss is among the first clinical signs in childhood forms of NCLs. Mutations in CLN5 underlie CLN5 disease. The aim of this study was to characterize how the lack of normal functionality of the CLN5 protein affects the mouse retina. Scotopic electroretinography (ERG) showed a diminished c-wave amplitude in the CLN5 deficient mice already at 1 month of age, indicative of pathological events in the retinal pigmented epithelium. A- and b-waves showed progressive impairment later from 2 and 3 months of age onwards, respectively. Structural and immunohistochemical (IHC) analyses showed preferential damage of photoreceptors, accumulation of autofluorescent storage material, apoptosis of photoreceptors, and strong inflammation in the CLN5 deficient mice retinas. Increased levels of autophagy-associated proteins Beclin-1 and P62, and increased LC3b-II/LC3b-I ratio, were detected by Western blotting from whole retinal extracts. Photopic ERG, visual evoked potentials, IHC and cell counting indicated relatively long surviving cone photoreceptors compared to rods. In conclusion, CLN5 deficient mice develop early vision loss that reflects the condition reported in clinical childhood forms of NCLs. The vision loss in CLN5 deficient mice is primarily caused by photoreceptor degeneration.

Retinal Degeneration In A Mouse Model Of CLN5 Disease Is Associated With Compromised Autophagy.

The eye possesses unique anatomical features that make it a valuable target for gene therapy applications.

Comparative Study of Adeno-associated Virus, Adenovirus, Bacu lovirus and Lentivirus Vectors for Gene Therapy of the Eyes.

To determine the efficacy of trabodenoson, an adenosine mimetic with highly selective adenosine A1 receptor binding properties, in a preclinical mouse model for dry-eye disease.

Efficacy of Trabodenoson in a Mouse Keratoconjunctivitis Sicca (KCS) Model for Dry-Eye Syndrome.

To determine the efficacy of the superoxide dismutase mimetic, manganese(III) tetrakis(1-methyl-4-pyridyl) porphyrin (Mn-TM-2-PyP), in vitro in human corneal epithelial (HCE-T) cells and in vivo in a preclinical mouse model for dry-eye disease (DED).

Manganese(III) tetrakis(1-methyl-4-pyridyl) porphyrin, a superoxide dismutase mimetic, reduces disease severity in in vitro and in vivo models for dry-eye disease.

Retinal explant cultures provide simplified systems where the functions of the retina and the effects of ocular therapies can be studied in an isolated environment. The purpose of this study was to provide insight into long-term preservation of retinal tissue in culture conditions, enable a deeper understanding of the interdependence of retinal morphology and function, and ensure the reliability of the explant technique for prolonged experiments.

Giedrius Kalesnykas

Experimentica Ltd.

In Vivo Multimodal Imaging and Analysis of Mouse Laser-Induced Choroidal Neovascularization Model

Oxygen-Induced Retinopathy Model for Ischemic Retinal Diseases in Rodents