Diabetic retinopathy (DR), recognized as a progressive neurovascular and microvascular complication of diabetes, remains one of the leading causes of visual disability worldwide, within the context of a sustained increase in ophthalmic diseases and retinal vascular disorders that compromise vision. This study aimed to characterize the progression of diabetic retinopathy in a streptozotocin (STZ)-induced Wistar rat model. A single dose of 65 mg/kg body weight was administered, with follow-up periods at 2, 4, 8, and 10 weeks, compared to healthy controls. STZ-induced rats exhibited reduced weight gain compared to the control group. They also showed markedly variable hyperglycemia, with glucose concentrations ranging from 250 to 530 mg/dL. Histological analysis of retinal tissue at week 4 revealed early signs of vascular compromise, including early indications of a microenvironment conducive to neovascularization and edema. By week 8, retinal damage had progressed to hemorrhage, persistent edema, and layer-specific vascular disruption. At week 10, intensified neovascularization and exacerbated edema indicated advanced microvascular deterioration. Immunofluorescence analysis demonstrated a temporal accumulation of CD8⁺ T cells in the retina, correlating with photoreceptor degeneration. The coordinated dynamics of CD4⁺ and CD8⁺ T cells suggested transient immune activation during STZ-induced retinal degeneration. Gene expression profiling revealed a proinflammatory and pro-oxidative retinal microenvironment, characterized by the overexpression of angiogenic pathways and proliferative signals. Simultaneously, the antioxidant response appeared partially impaired. Collectively, these findings provide mechanistic perspective on the multifactorial nature of diabetic retinopathy. Oxidative stress, inflammation, and angiogenesis converge to disrupt retinal homeostasis. This experimental model may serve as a reliable platform for future studies aimed at elucidating disease pathophysiology, identifying novel therapeutic targets, and evaluating emerging ophthalmic antidiabetic interventions.

Several chronic inflammatory processes are currently being studied in relation to other systems to better understand the regulation mechanisms and identify potential therapeutic targets. A significant body of evidence supports the role of the nervous system in regulating various immunological processes. This study investigates the relationship between pterygia and the sympathetic nervous system, focusing on their interaction in the inflammatory response and fibrogenic process. Sixteen surgical specimens of primary pterygia and four conjunctival tissue samples were examined, and their morphology was analyzed using hematoxylin–eosin and Masson’s trichrome stains. The gene expression of adrenergic receptors, as well as inflammatory and fibrogenic cytokines, was also assessed. Additionally, both adrenergic receptors and tyrosine hydroxylase were found to be localized within the tissues according to immunohistochemistry and immunofluorescence techniques. Increased expression of proinflammatory, fibrogenic, and adrenergic genes was observed in the pterygium compared to the healthy conjunctiva. Adrenergic receptors and tyrosine hydroxylase were localized in the basal region of the epithelium and within blood vessels, closely associated with immune cells. Neuroimmunomodulation plays a key role in the pathogenesis of pterygia by activating the sympathetic nervous system. At the intravascular level, norepinephrine promotes the migration of immune cells, thereby sustaining inflammation. Additionally, sympathetic nerve fibers located at the subepithelial level contribute to epithelial growth and the fibrosis associated with pterygia.