Abstract
Diabetic retinopathy remains a primary source of blindness with the growing pandemic of diabetes. Numerous studies have shown that early neurodegeneration caused by elevated oxidative stress may initiate microvascular damage in the diabetic retina during the last few decades. A variety of preventive and treatment strategies using phytochemicals that possess high antioxidants have shown great promise in reducing diabetes-induced neurodegeneration retinal damage. In this investigation, we employed an extract of Loranthus regularis, a traditional medicinal herb which is found to improve diabetes and associated complications in experimental studies. We orally treated STZ-induced diabetic rats with L. regularis and analyzed the neurodegenerative factors in the retina. After treatments, we used Western blotting techniques to analyze the protein content of neurotrophic factors (NGF, BDNF, TrkB), apoptotic factors (cytochrome c, Bcl-2, Bax), and phosphorylation of AKT in the diabetic retina. Additionally, we used ELISA methods to measure the contents of BDNF and the activity of Caspase-3 and biochemical procedures to determine the levels of glutathione and lipid peroxidation (TBARS). Our findings show that L. regularis treatments resulted in a considerable increase in neurotrophic factors and a decrease in apoptotic factors in the diabetic retina. Furthermore, in diabetic retina treated with L. regularis, the level of Bcl-2 protein increased, while the phosphor-AKT signaling improved. As a result, L. regularis may protect against diabetic-induced retinal neuronal damage by increasing neurotrophic support and reducing oxidative stress and apoptosis. Therefore, this study suggests that in diabetic retinopathy, L. regularis could be a potential therapy option for preventing neuronal cell death.