curcumin and Ocular-Hypertension

Curcumin (1,7-bis-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5dione) is a polyphenol extracted from turmeric that has long been advocated for the treatment of a variety of conditions including neurodegenerative and inflammatory disorders. Despite this promise, the clinical use of curcumin has been limited by the poor solubility and low bioavailability of this molecule. In this article, we describe a novel nanocarrier formulation comprising Pluronic-F127 stabilised D-α-Tocopherol polyethene glycol 1000 succinate nanoparticles, which were used to successfully solubilize high concentrations (4.3 mg/mL) of curcumin. Characterisation with x-ray diffraction and in vitro release assays localise curcumin to the nanocarrier interior, with each particle measuring <20 nm diameter. Curcumin-loaded nanocarriers (CN) were found to significantly protect against cobalt chloride induced hypoxia and glutamate induced toxicity in vitro, with CN treatment significantly increasing R28 cell viability. Using established glaucoma-related in vivo models of ocular hypertension (OHT) and partial optic nerve transection (pONT), topical application of CN twice-daily for three weeks significantly reduced retinal ganglion cell loss compared to controls. Collectively, these results suggest that our novel topical CN formulation has potential as an effective neuroprotective therapy in glaucoma and other eye diseases with neuronal pathology.

Topics: Animals; Cell Survival; Curcumin; Dynamic Light Scattering; Eye Diseases; Immunohistochemistry; Male; Microscopy, Confocal; Microscopy, Electron, Transmission; Nanoparticles; Nanostructures; Ocular Hypertension; Rats; Spectroscopy, Fourier Transform Infrared; X-Ray Diffraction

The involvement of local and systemic oxidative stress in intraocular pressure (IOP) elevation and optic nerve damage has been hypothesized in the pathogenesis of glaucoma. In this study, we aim to evaluate the antioxidant effects of curcumin in BV-2 microglia oxidative damage and assess its neuroprotective effects in a chronic high IOP rat model.. BV-2 microglia cell line was used in an in vitro study and Wistar rats were used in an in vivo study. Cultured BV-2 microglia cells were pretreated with 10, 1, or 0.1 μM curcumin for 1 h, and sustained oxidative stress was induced by subjecting BV-2 microglia to 200 μM hydrogen peroxide (H2O2) for 24 h. MTT assay was used to determine cell viability. Changes of intracellular reactive oxygen species (ROS) and apoptosis were analyzed by flow cytometry. Three episcleral veins were cauterized to induce high IOP in Wistar rats and measured by Tonopen. After 6 weeks of treatment with curcumin (10 mg/kg/day) by intragastric administration, surviving of retinal ganglion cells was quantified. Activation of caspase 3, cytochrome c, BAX, and BCL2 was quantified by Western blotting both in BV-2 microglia and in animal model. Data were analyzed with the GraphPad Prism 5.0 software, and P<0.05 was considered to be statistically significant.. The in vitro study showed that when BV-2 microglia was pretreated with curcumin, the cell viability increased and the intracellular ROS and apoptosis significantly decreased. In the in vivo study, chronic mild IOP elevation was induced for 4 weeks. In the curcumin-treated group, curcumin protected rat BV-2 microglia from death significantly. In both H2O2-treated BV-2 microglia and glaucoma models, caspase 3, cytochrome c, and BAX were downregulated and BCL2 was upregulated in the curcumin-treated group.. Curcumin affords neuroprotective effects by inhibiting oxidative damage and could be a new or adjunctive treatment for glaucoma.

Topics: Animals; Apoptosis; Cell Line; Cell Survival; Curcumin; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Flow Cytometry; Humans; Intraocular Pressure; Microglia; Neuroprotective Agents; Ocular Hypertension; Oxidative Stress; Rats, Wistar; Reactive Oxygen Species