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Oxidative stress (OS), which increases during diabetes, exacerbates the development and progression of diabetes
complications including renal vascular and proximal tubule cell dysfunction. The objective of this study was to
investigate the changes in the metabolic state of the tissue in diabetic mice kidneys using fluorescence imaging.
Mitochondrial metabolic coenzymes NADH (Nicotinamide Adenine Dinucleotide), and FADH-2 (Flavin Adenine
Dinucleotide) are autofluorescent and can be monitored without exogenous labels by optical techniques. The ratio of the
fluorescence intensity of these fluorophores, (NADH/FAD), called the NADH redox ratio (RR), is a marker of metabolic
state of a tissue. We examined mitochondrial redox states of kidneys from diabetic mice, Akita/+ and its control wild
type (WT) for a group of 8- and 12-week-old mice. Average intensity and histogram of maximum projected images of
FAD, NADH, and NADH RR were calculated for each kidney. Our results indicated a 17% decrease in the mean NADH
RR of the kidney from 8-week-old mice compared with WT mice and, a 30% decrease in the mean NADH RR of kidney
from12-week-old mice compared with WT mice. These results indicated an increase in OS in diabetic animals and its
progression over time. Thus, NADH RR can be used as a hallmark of OS in diabetic kidney allowing temporal
identification of oxidative state.
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