Protective effects of nano/submicron lycium barbarum fruits against oxidative stress – induced diabetic retinopathy in animal models
Date Issued
2012
Date
2012
Author(s)
Chen, Yun-Ju
Abstract
Diabetes mellitus (DM) is an important disease not only because of its high prevalence but also the disabling systemic complications. In eyes, DM can cause microvascular complication, called diabetic retinopathy (DR). It is a major cause of vision loss in young adults in the developing world and therefore a critical public health issue. Multiple biochemical abnormalities have been documented to be responsible for the pathogenesis of diabetic retinopathy. However, no single event predominates. Among the various pathways and effector molecules, oxidative stress plays a crucial role. Hyperglycemia in DM patients can induce ROS (Reactive oxygen species) production, which stimulates downstream inflammatory mediators and finally causes retinal capillary cells apoptosis. These inflammation-related chemokines and cell adhesion molecules are proved to be related to DR.
Lycium barbarum (LB) fruits, a kind of medicinal plant used in East Asia for over 2300 years, have been studied to posses anti-aging, antioxidant and neuroprotective effects. The active biological activity of LB fruits comes from LBP (Lycium barbarum polysaccharide), zeaxanthin and other small molecules. Some studied showed its antioxidant capacity in various animal models with oxidative stress induced in skin, muscle and liver. However, its protective effect on eyes or retinal tissues has not been fully elucidated.
Therefore, in our study, we investigated if LB fruits had protective effects on DR via antioxidation and anti-inflammation properties. Besides, we also applied nano-technique to prepare LB fruits and assumed this would increase its bioavailability.
In this study, we successfully established a diabetic animal model by intraperitoneal injection of STZ. The result proved that treatment with LB fruits for 60 days could reduce systemic total cholesterol, triglyceride and free radicals as well as urine sugar. In eyes, free radicals and some inflammatory markers including ICAM-1, MCP-1, RANTES, IL-8 and iNOS expressions in aqueous humor and retinas also decreased after treatment of LB fruits. Expression of three oxidative stress responders：HO-1, Prx-1 and TRX also attenuated, reflecting suppressed oxidative stress. In histological changes, retinal sections showed less staining for acrolein, nitrotyrosin and 8-OHdG after LB fruits treatment, indicating inhibited oxidative damages on lipid, protein and DNA.
Milled LB fruits had better protection over blended ones in some aspects, bot not all of the tested markers. So the superior effects of LB fruits after nanotechnology -processing may need further investigations.
Our study concluded that LB fruits had antioxidation and anti-inflammation effects in eyes, in diabetic animal models. The milled LB fruits may have enhanced protection over blended ones. Therefore, LB fruits may serve as an alternative or supplementary treatment in diabetic retinopathy.
Subjects
Lycium barbarum
diabetic retinopathy
oxidative stress
SDGs
Type
thesis
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