Downregulation of VEGF mRNA expression by triamcinolone acetonide acetate-loaded chitosan derivative nanoparticles in human retinal pigment epithelial cells

BACKGROUND: The purpose of this study was to investigate the downregulation of mRNA expression of vascular endothelial growth factor (VEGF) by triamcinolone acetonide acetate (TAA)-loaded chitosan nanoparticles in human retinal pigment epithelial cells. METHODS: TAA-loaded deoxycholic acid-modified chitosan (TAA/DA-Chit) nanoparticles were prepared via a self-assembly mechanism, and their morphology and zeta potential were examined by transmission electron microscopy and zeta potential analysis, respectively. DA-Chit and TAA/DA-Chit nanoparticle toxicity was evaluated using a Cell Counting Kit-8 assay. The efficiency of cellular uptake was determined using fluorescein isothiocyanate-labeled DA-Chit nanoparticles, in place of TAA/DA-Chit nanoparticles, assessed by both inverted fluorescence microscopy and flow cytometry. Downregulation of VEGF mRNA expression by TAA/DA-Chit nanoparticles was further investigated by real-time reverse transcription polymerase chain reaction (RT-PCR) assay of the treated human retinal pigment epithelial cells. RESULTS: TAA/DA-Chit nanoparticles were prepared with a TAA-loading capacity in the range of 12%–82%, which increased the water solubility of TAA from 0.3 mg/mL to 2.1 mg/mL. These nanoparticles showed oblate shapes 100–550 nm in size in transmission electron microscopic images and had positive zeta potentials. The Cell Counting Kit-8 assay indicated that the DA-Chit and TAA/DA-Chit nanoparticles had no toxicity and low toxicity, respectively, to human retinal pigment epithelial cells. Fluorescein isothiocyanate-labeled DA-Chit nanoparticle uptake by human retinal pigment epithelial cells was confirmed by inverted fluorescence microscopy and flow cytometry. Real-time RT-PCR assay showed that the VEGF mRNA level decreased after incubation of human retinal pigment epithelial cells with TAA/DA-Chit nanoparticles. CONCLUSION: TAA/DA-Chit nanoparticles had a downregulating effect on VEGF mRNA expression in human retinal pigment epithelial cells and low cytotoxicity, which might be beneficial characteristics for the development of future treatment for diabetic retinopathy.