Purchase this article with an account.
Teruyo Kida, Hidehiro Oku, Masanori Fukumoto, Yoshitaka Okuda, Seita Morishita, Taeko Horie, Hiroyuki Suzuki, Takatoshi Kobayashi, Tsunehiko Ikeda; Possible involvement of aquaporin 4 and nitric oxide in the high glucose-induced swelling of Muller cells in rat retina.. Invest. Ophthalmol. Vis. Sci. 2016;57(12):3210.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Aquaporin 4 (AQP4), a water channel protein, is closely associated with brain edema. AQP4 is known to express in the retinal Muller cells. The purpose of this study was to investigate whether AQP4 and nitric oxide (NO) is involved in the retinal edema caused by high glucose condition.
Retinas from diabetic rats and cultured Muller cells were prepared for this study. Intravitreal injection of VEGF or PBS was performed either in the streptozotocin (STZ) induced diabetic (BS > 300 mg/dl) or healthy rats. After perfused fixation under deep anesthesia with pentobarbital, retina tissues were removed. Retinal sections were immunostained by using the following antibodies; mouse anti-glial fibrillary acidic protein (GFAP), rabbit anti-rat AQP4, and VEGF. Intracellular levels of NO were determined in Muller cells that were cultured at high glucose concentrations (25 mM) in the presence or absence of TGN-020, a selective AQP4 inhibitor, using 4,5-diaminofluorescein diacetate and flow cytometry (FACS). Protein levels of nitric oxide synthase (NOS) and VEGF in Muller cells were also determined by western blot analysis.
AQP4 immunoreactivity was concentrated along vessels, in the ganglion cell layer and in the outer plexiform layer. The expression of AQP4 and VEGF were colocalized with GFAP. In addition, immunoreactivity to AQP4 and VEGF in the diabetic rat retina were much higher than the control. The expressions of NOS and VEGF determined by immunoblot were significantly increased in cultured Muller cells under high glucose conditions. Intracellular NO level of Muller cells was increased under glucose condition. Addition of TGN-020 suppressed the increase. In addition, exposure to high glucose caused the enlarged cellular volume and TGN-020 also suppressed the enlargement.
The results that high glucose condition induced NO which then increased AQP4 expression of Muller cells, may suggest NO can be an inducer of diabetic retinal edema associated with Muller cell swelling.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
This PDF is available to Subscribers Only