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Joy Zhang, Yue Li, Tongrong Zhou, Paul A Edwards, Hua Gao, Xiaoxi Qiao; Effects of Metformin Treatment on Retinal Blood Flow in Diabetic Mice. Invest. Ophthalmol. Vis. Sci. 2017;58(8):78.
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© ARVO (1962-2015); The Authors (2016-present)
Metabolic alterations in diabetes can affect retinal blood flow. In this study, we qualitatively assess the effect of metformin treatment on retinal blood flow in a diabetic mouse model.
Diabetes was induced in young adult C57BL/6 mice by intraperitoneal injection of streptozotocin (STZ) in 5 consecutive days. Metformin hydrochloride oral solution was given to the mice by gavage at 200 mg/kg/d after STZ injection for 10 weeks. The retinal vasculature was evaluated by fluorescent angiography (FA) at 6 and 10 weeks in wild-type, STZ-induced diabetic, and metformin-treated STZ diabetic mice. FA videos were recorded using a Micron III retinal imaging microscope and analyzed using ImageJ and MATLAB.
There were no notable abnormal changes in all mice on Fundus examination. FA revealed no visible retinal vascular leakage in any mice. In pixel-by-pixel analysis of FA videos, the ratio of pixels that corresponds to early perfusion was similar among the three groups. A smooth and moderate increase of pixel ratio that represents late-stage perfusion was seen in wild type mice. In contrast, the ratio of late-stage pixels in STZ diabetic mice was almost doubled when compared with wild type controls, indicating a significantly delayed and prolonged retinal circulation time at late stage in these diabetic mice. With metformin treatment, a lower ratio of late-stage pixels was observed in the diabetic mice, suggesting a potentially partial protective effect on late stage perfusion. Overall, these retinal perfusion changes were noticed at 6 weeks and remained unaltered at 10 weeks.
These results indicate that diabetes causes significant delay and prolongation of retinal perfusion in mice, and that metformin treatment may inhibit such alterations.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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