Curcumin Improves Insulin Sensitivity and Ameliorates Serum Pro-inflammatory Cytokines Levels in Diabetes Rat model Irrespective of type of Diabetes

Objectives: To evaluate the impact of type of diabetes on serum levels of pro-inflammatory cytokines and the effect of chronic administration of curcumin on their levels in experimentally-induced diabetes in albino rats. The study included 60 (20 as control group) male albino rats; diabetes mellitus (DM) was induced using intraperitoneal injection of a single dose of 50 mg/kg of streptozotocin (STZ) after animals were maintained on high-fat diet for 2-weeks (20 rats) for induction of non-insulin dependent DM (NIDDM) or without dieting regimen for induction of IDDM (20 rats). One-week later, rats received oral curcumin (200 mg/kg). Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) and rapid insulin sensitivity test (RIST) were used for clinical assessment. Two fasting venous blood samples were obtained after induction of diabetes and prior to initiation of therapy and at 6-wks after treatment for calorimetric estimation of fasting blood glucose (FBG) and ELISA estimation of fasting plasma insulin (FPI), serum interleukin (IL)-1β and -6 and tumor necrosis factor-α (TNF-α). Results: Curcumin induced significant reduction of FBG levels, irrespective of type of diabetes and in NIDDM animals, post-treatment FPI levels were significantly lower compared to their pre-treatment levels. Diabetes, irrespective of its type, induced significantly higher pre-treatment serum levels of pro-inflammatory cytokines in both study groups compared to control group. However, curcumin significantly lowered serum levels of estimated cytokines at 6-weeks after treatment compared to pre-treatment levels. In group II, post-treatment RIST index was non-significantly higher compared to control index. In group III, pre-treatment HOMA-IR index was significantly higher compared to control index, while post-treatment HOMA-IR index was significantly lower compared to pretreatment levels, despite still being significantly higher compared to control group. It is concluded that chronic administration of curcumin improves insulin sensitivity and thus imposing an anti-diabetic effect manifested as decreased FBG levels with concomitant decreased FPI and ameliorated the increased serum levels of proinflammatory cytokines and such effects are manifested in both types of diabetes. [Mohamed Khaled Mohamed Mahfouz. Curcumin Improves Insulin Sensitivity and Ameliorates Serum Proinflammatory Cytokines Levels in Diabetes Rat model Irrespective of type of Diabetes. Journal of American Science 2011;7(6):794-799]. (ISSN: 1545-1003). http://www.americanscience.org.