[Comparative study of retinopathy in C57BL/6 and eNOS-knockout mouse models of type 1 diabetes mellitus]

Area of Science:

• Ophthalmology
• Endocrinology
• Genetics

Background:

• Type 1 diabetes mellitus (T1DM) is a metabolic disorder with significant ocular complications.
• Diabetic retinopathy (DR) is a leading cause of vision loss, necessitating robust animal models for research.
• Endothelial nitric oxide synthase (eNOS) plays a crucial role in vascular health and may be implicated in DR pathogenesis.

Purpose of the Study:

• To compare retinal function and vascular pathologies in C57BL/6 and eNOS-knockout (eNOS(-/-)) mouse models of T1DM.
• To evaluate the utility of these models in representing the development of diabetic retinopathy.

Main Methods:

• Type 1 diabetes mellitus was induced using streptozotocin (STZ) in C57BL/6 and eNOS(-/-) mice.
• Retinal function was assessed using electroretinogram (ERG).
• Retinal vascular pathologies were evaluated via fluorescein angiography (FFA), immunofluorescence staining, and retinal ganglion cell counts.

Main Results:

• Both diabetic C57BL/6 and eNOS(-/-) mice exhibited reduced ERG a-wave and b-wave amplitudes and fewer retinal ganglion cells.
• Diabetic eNOS(-/-) mice displayed tortuous retinal vessels.
• eNOS(-/-) mice showed more severe retinal functional and vascular pathologies with a faster onset compared to C57BL/6 mice.

Conclusions:

• The eNOS(-/-) mouse model demonstrates a more pronounced and rapid development of diabetic retinopathy features.
• eNOS(-/-) mice provide a more representative model for studying diabetes and diabetic retinopathy.
• This study highlights the importance of eNOS in the pathogenesis of diabetic vascular complications in the retina.