An Aqueous Extract of Radix Astragali, Angelica sinensis, and Panax notoginseng Is Effective in Preventing Diabetic Retinopathy

Diabetic retinopathy (DR), in which inflammation has been implicated playing important roles, is one of the most common diabetes complications. Dang Gui Bu Xue Tang (DBT), an aqueous extract of Radix Astragali and Radix Angelica sinensis, is a classical prescription in Traditional Chinese Medicine for treating inflammation and ischemic diseases. Here, we investigated the effects of a modified recipe of DBT, with addition of Panax notoginseng, in treating diabetic retinopathy. An aqueous extract of Radix Astragali, Radix Angelica sinensis, and Panax notoginseng (RRP) was given to Goto-Kakizaki (GK) rats and streptozotocin-induced Sprague-Dawley (SD) rats. Leukostasis, vascular leakage, and acellular capillaries in retinal vasculature of animals were determined. Expression of retinal inflammatory biomarkers was assessed. We found that RRP reduced leukostasis, acellular capillaries, and vascular leakage compared to diabetic control rats. We also found that RRP decreased the expression of inflammatory factors including IL-1 beta, IL-6, TNF-alpha, NF-kappa B, MCP-1, ICAM-1, or VCAM-1 in the retinas of GK rats and reversed high glucose-induced inhibition of endothelial cell migration and proliferation in vitro. We conclude that RRP has a potent effect in preventing the pathogenesis and/or progression of DR and thus may serve as a promising nontoxic therapeutic approach of DR.