International Journal of Ophthalmology (Jun 2017)

Scutellaria barbata attenuates diabetic retinopathy by preventing retinal inflammation and the decreased expression of tight junction protein

  • Xi-Yu Mei,
  • Ling-Yu Zhou,
  • Tian-Yu Zhang,
  • Bin Lu,
  • Li-Li Ji

DOI
https://doi.org/10.18240/ijo.2017.06.07
Journal volume & issue
Vol. 10, no. 6
pp. 870 – 877

Abstract

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AIM: To observe the attenuation of ethanol extract of Herba Scutellaria barbata (SE) against diabetic retinopathy (DR) and its engaged mechanism. METHODS: C57BL/6J mice were intraperitoneally injected with streptozotocin (STZ, 55 mg/kg) for 5 consecutive days to induce diabetes. The diabetic mice were orally given with SE (100, 200 mg/kg) for 1mo at 1mo after STZ injection. Blood-retinal barrier (BRB) breakdown was detected by using Evans blue permeation assay. Real-time polymerase chain reaction (RT-PCR), Western blot and immunofluorescence staining were used to detect mRNA and protein expression. Enzyme-linked immunosorbent assay (ELISA) was used to detect serum contents of tumor necrosis factor-α (TNF-α) and interleukin (IL)-1β. RESULTS: SE (100, 200 mg/kg) reversed the breakdown of BRB in STZ-induced diabetic mice. The decreased expression of retinal claudin-1 and claudin-19, which are both tight junction (TJ) proteins, was reversed by SE. SE decreased the increased serum contents and retinal mRNA expression of TNF-α and IL-1β. SE also decreased the increased retinal expression of intercellular cell adhesion molecule-1 (ICAM-1). SE reduced the increased phosphorylation of nuclear factor kappa B (NFκB) p65 and its subsequent nuclear translocation in retinas from STZ-induced diabetic mice. Results of Western blot and retinal immunofluorescence staining of ionized calcium-binding adapter molecule 1 (Iba1) demonstrated that SE abrogated the activation of microglia cells in STZ-induced diabetic mice. CONCLUSION: SE attenuates the development of DR by inhibiting retinal inflammation and restoring the decreased expression of TJ proteins including claudin-1 and claudin-19.

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