Noscapine Alleviates Hyperglycemia-triggered Retinal Microangiopathy in STZ-treated Rats

Background As diabetes continues to be a global epidemic, the prevalence of retinopathy, a frequent microvascular complication, is anticipated to increase significantly. Effective management of blood glucose, blood pressure, and lipid levels may reduce the risk of diabetic retinopathy (DR); however, maintaining optimal control remains challenging in clinical practice. In advanced stages, therapeutic interventions such as anti-vascular endothelial growth factor (VEGF) medication, laser photocoagulation, and vitrectomy are necessary to preserve vision; however, they render side effects, and vision recovery is not 100%. Purpose We aimed to investigate the efficacy of bioactive alkaloid noscapine to mitigate DR. Materials and Methods Hyperglycemia was triggered in male Wistar rats with streptozotocin (STZ) and treated with noscapine. The impact of noscapine on regulating STZ-induced hyperglycemia was analyzed by quantifying the glycated hemoglobin and blood glucose levels. The body weight, feed intake, and cholesterol levels of the experimental animals were monitored to assess the lipid-lowering efficacy of noscapine. To assess the inhibitory potency of noscapine against hyperglycemia-triggered oxidative stress, the malondialdehyde (MDA) levels and the anti-oxidant levels were quantified. Inflammatory proteins were measured to evaluate the efficacy of noscapine in hyperglycemic rats. VEGF, MCF-1, and matrix metallopeptidase 9 (MMP-9) protein levels were quantified in the experimental rats to analyze the mitigating potency of noscapine against hyperglycemia-triggered DR. The retinal histopathological analysis and apoptotic protein levels in the experimental animals were performed to confirm the ameliorative efficacy of noscapine against hyperglycemia-induced retinopathy. Results Results from various analyses proved noscapine treatment effectively attenuated hyperglycemia and hypercholesterolemia in the STZ-administered rats. It also scavenged free radicals, enhanced anti-oxidant status, and thereby inhibited ROS-induced inflammation and apoptosis in hyperglycemia-triggered rats. The levels of VEGF, MCF-1, and MMP-9 were significantly decreased with noscapine treatment, which signifies its anti-angiogenic effect in treating DR, and it is further confirmed with our retinal histopathological analysis. Conclusion Overall, our study demonstrates that noscapine is a potent anti-hyperglycemic and anti-oxidant agent, showing significant ameliorative effects against retinopathy in a diabetic rat model.