Abstract

PREVENTION OF PROTEIN KINASE C ISOZYMES ELEVATION BY FLAXSEED OIL IN EXPERIMENTAL DIABETES

Jihan Hussein*, Dina Abo El-Matty, Olfat Shaker , Zakaria El-Khayat,Wafaa Rasheed, and Jakleen Raafat

ABSTRACT

Protein kinase C (PKC) is a key enzyme in insulin action and the activation of PKC isoforms prevents phosphoinositide -3- kinase (PI3K) pathway at the insulin receptor substrate level, which affects several signaling molecules related to this pathway. Arachidonic acid(AA) and oleic acid ( OA) are thought to stimulate PKC isoforms activity through direct interactions with binding sites in the regulatory domain of the enzyme. The main objective of this study was to evaluate the role of flaxseed oil supplementation in prevention of protein kinase C isozymes elevation in experimental diabetes and then its role in reducing insulin resistance. Sixty male albino rats were used in this study and divided into four groups : control, flaxseed oil, diabetic and treated groups. After the experimental period ( 8 weeks ) , fasting blood sugar and insulin were estimated. Erythrocyte membrane AA and α linolenic acid (ALA) were determined by HPLC column C 18 ( 260 X 4.6 , particle size 5 μl ) , mobile phase was acetonitrile / water mixture (70/30) v/v by isocratic elution with flow rate 1 ml / min and 200 nm wave length. PKC βII and PKC γ were estimated by PCR . PKC βII , PKC γ and AA were significantly increased in diabetic group while flaxseed oil supplementation significantly decreased these values in treated group. In conclusion, flaxseed oil supplementation increased erythrocyte membrane ALA and decreased AA resulting in a prevention of PKC isozymes elevation and improving insulin sensitivity in experimental diabetes.

Keywords: PKC, fatty acids, flaxseed oil, insulin resistance, HPLC.