The Effect of Water Extract of Zataria multiflora on Microvascular Permeability in Streptozocin Induced Diabetic Rats

Objectives: The present investigation was aimed to study the effect of water extract of Zataria multiflora (Z. multiflora) on microvascular permeability in streptozocin (STZ)-induced diabetic rats.
Place and Duration of Study: Physiology Research Center, Kerman University of Medical Sciences, Kerman, Iran, between June, 2011 and June 2012.
Materials and Methods: diabetes was induced in rats by administration of STZ (55 mg/kg, i.p.). Z. multiflora (1000mg/kg/d) and glibenclamide (5mg/kg) were administered by intragastric gavage for 8 weeks after the induction of diabetes. Control, vehicle and STZ_induced diabetes groups received the same volume of distilled water as Z. multiflora treated group. The fasting body weight, blood glucose level and glycated haemoglobin A1c (HbA1c) levels were estimated at the start of experiments and at the end of every 2 week for 8 weeks. Microvascular permeability was evaluated by the evans blue test and water content measurement, 8 weeks after the induction of diabetes.
Results: Z. multiflora caused a significant reduction in extravasated evans blue concentration (31.4±0.8µg/100mg) in STZ diabetics vs 12.3±0.7µg/100mg in Z. multiflora treated diabetic rats), (P< .001) as an indicator of microvascular permeability. However, Z. multiflora had no significant effect on water content percentage (80.2±0.1%) compared to STZ diabetic rats (81.4±0.5%). Also Z. multiflora administration caused a significant decrease in blood glucose level (P=.05), HbA1c level (P<.001) and body weight loss (P=.01) in STZ diabetic rats.
Conclusion: this study showed that Z. multiflora reduced microvascular permeability in STZ diabetic rats. The underlying mechanism(s) is not determined yet, but the H1-receptor inhibition, antioxidant and/anti-inflammatory effect of Z. multiflora may be involved in its benefit effects on STZ- induced diabetes.