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Updated: Jun 13, 2026
An Assay to Detect Protection of the Retinal Vasculature from Diabetes-Related Death in Mice
Published on: January 12, 2024
Diabetic eNOS-knockout mice develop accelerated retinopathy
Qiuhong Li1, Amrisha Verma, Ping-Yang Han
1Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, Florida 32610-0284, USA. qli@ufl.edu
Purpose:
Dysfunction of endothelial nitric oxide synthase (eNOS) has been implicated in the pathogenesis of diabetic vascular complications. This study was undertaken to determine the role of eNOS in the development of diabetic retinopathy (DR), by investigating the functional consequences of its deficiency in the diabetic state.
Methods:
Diabetes was induced in eNOS-knockout (eNOS(-/-)) and C57B/6 mice by streptozotocin (STZ) injection. Retinal vasculature was evaluated by albumin extravasation, to quantitatively measure vascular permeability, and by trypsin-digested retinal vascular preparations, to quantify acellular capillaries. Gliosis was evaluated by immunofluorescent techniques. Retinal capillary basement membrane thickness was assessed by transmission electron microscopy. Total retinal nitric oxide level was assessed by measuring nitrate/nitrite using a fluorometric-based assay, iNOS expression was examined by real-time PCR.
Results:
Diabetic eNOS(-/-) mice exhibit more severe retinal vascular permeability than age-matched diabetic C57BL/6 mice, detectable as early as 3 weeks after diabetes induction. Diabetic eNOS(-/-) mice also show earlier onset and an increased number of acellular capillaries, sustained gliosis, and increased capillary basement membrane thickness. Total nitric oxide (NO) level was also increased, concomitant with elevated iNOS expression in diabetic eNOS(-/-) retina.
Conclusions:
Diabetic eNOS(-/-) mice exhibit A significantly wider range of advanced retinal vascular complications than the age-matched diabetic C57BL/6 mice, supporting the notion that eNOS-derived NO plays an essential role in retinal vascular function. This mouse model also faithfully replicates many of the hallmarks of vascular changes associated with human retinopathy, thus providing a unique model to aid in understanding the pathologic mechanisms of and to develop effective therapeutic strategies for diabetic retinopathy.
Insights
Endothelial nitric oxide synthase (eNOS) deficiency exacerbates diabetic retinopathy in mice, increasing vascular permeability and complications. This highlights eNOS-derived nitric oxide's crucial role in maintaining retinal vascular health.
Area of Science:
- Ophthalmology
- Vascular Biology
- Diabetology
Background:
- Endothelial nitric oxide synthase (eNOS) dysfunction is linked to diabetic vascular issues.
- Diabetic retinopathy (DR) is a major microvascular complication of diabetes.
Purpose of the Study:
- To investigate the role of eNOS in diabetic retinopathy development.
- To examine the functional consequences of eNOS deficiency in diabetic conditions.
Main Methods:
- Diabetes induced in eNOS-knockout and wild-type mice using streptozotocin.
- Assessed retinal vascular permeability, acellular capillaries, gliosis, and basement membrane thickness.
- Measured nitric oxide levels and inducible nitric oxide synthase (iNOS) expression.
Main Results:
- Diabetic eNOS-knockout mice showed significantly increased retinal vascular permeability.
- Accelerated onset and increased acellular capillaries, gliosis, and basement membrane thickening were observed.
- Elevated nitric oxide levels and iNOS expression were noted in diabetic eNOS-knockout retinas.
Conclusions:
- eNOS-derived nitric oxide is essential for maintaining retinal vascular function in diabetes.
- The eNOS-knockout mouse model effectively replicates human diabetic retinopathy vascular changes.
- This model aids in understanding DR pathogenesis and developing therapeutic strategies.
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01:27Diabetic Retinopathy
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