Effects of Usnic Acid on Hyperglycemia and Renal Function in Streptozotocin-Induced Diabetic Rats

Abstract

1. Abstract 1.1. Background : Diabetic hyperglycemia and glomerular hyper filtration play a causative role in the progression of chronic kidney disease. Renal glucose handling via Sodium-Glucose Cotransporter (SGLT)-2 is a targetable approach and SGLT-2 inhibitors have proven therapeutic benefits in diabetic kidney disease. Usnic Acid (UA) is an active constituent of lichen species and symbiotic organism of algae and fungi, which is variously studied in folk medicine. The objective of this study was to demonstrate the beneficial effects of UA on glucose homeostasis and renal function in streptozotocin-induced diabetic Sprague-Dawley rats and to determine whether UA has an effect on regulation of SGLT that may further aid in glucoregulation and renal function. 1.2. Methods : Type 1 diabetes was induced in Sprague-Dawley rats with Streptozotocin (STZ, 60mg/kg) by intraperitoneal route on day 0. Diabetic rats were treated with UA (75 mg/kg) from day 15 to 35 via oral gavage. On day 35, urine was collected and Oral Glucose Tolerance Test (OGTT) was performed. After OGTT, blood was collected through cardiac puncture and kidneys were preserved for biochemical analysis. The results are expressed as mean ± standard error of the mean for n=8 rats per study group. The data were subjected to 1-way or 2-way ANOVA with Bonferroni’s multiple comparison post hoc test using Graph Pad Prism 5 and were considered significant at p ≤ 0.05. 1.3. Results : Diabetic rats chronically treated with UA had improved hyperphagia, hyperglycemia and glucose intolerance, glomerular hyper filtration, and urinary protein excretion (p 1.4. Conclusions : Based on preliminary findings we conclude that chronic treatment of UA may act in an insulin-independent manner in lowering of diabetic hyperglycemia and improvement of renal function. 2. Keywords: Glucosuria; Hyperglycemia; Renal Function; Sodium-Glucose Cotransporter; Usnic Acid