HYPOCHOLESTEROLEMIC EFFECT OF NIGELLA SATIVA AND WITHANIA SOMNIFERA IN LAYERS WITH REFERENCE TO HEPATIC AND OVARIAN FOLLICLE EXPRESSION OF CHOLESTEROL RELATED GENES

Abstract

The regulation of cholesterol synthesis and uptake from plasma is dependent on coordinated changes in the level of mRNAs of key genes that are known to regulate cholesterol synthesis and cholesterol uptake. Sterol regulatory element binding proteins (SREBP)-1 and -2 are transcription factors for the LDLr gene and are critical molecules in the feedback system of cholesterol metabolism. In the present study, the effect of Nigella Sativa and                          Withania Somnifera on serum and egg cholesterol and expression of SREBP-2 and LDLr gene was determined in liver and ovarian follicles of layers. The experimental birds were fed one of four different diets supplemented with Nigella Sativa and Withania Somnifera for 84 days. Blood and egg samples were collected for determining cholesterol content and liver and ovarian follicles were collected for the gene expression analysis. Total RNA was isolated from the collected tissues following standard TRIzol method for first- strand cDNA synthesis. Expression of SREBP-2 and LDLr genes was quantified using gene specific primer pairs with Real–Time PCR. Nigella Sativa and Withania Somnifera alone and in combination, significantly decreased the serum and egg cholesterol and significantly increased the mRNA expression levels of Sterol Regulatory Element Binding Protein-2 (SREBP-2) and Low-Density Lipoprotein receptor (LDLr) gene in liver and ovarian follicles of layers indicating the hypocholesterolemic activity of these herbs.