New mechanism in the modulation of carbon tetrachloride hepatotoxicity in rats using different natural antioxidants.

Transforming growth factor-ß (TGF-ß1) enhances the expression of apoptosis induced by certain cytokines and oncogenes. Activation of small mother against decapentaplegic (Smads) by TGF-ß results in fibrotic, apoptotic processes. PI-3/AKT focal adhesion kinase-phosphatidylinositol3-kinase (AKT), the mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription-3 (STAT3) pathways are influence in COX-2 and VEGF-stimulating pathways. NF-E2-related factor-2 (Nrf2) is an essential transcription factor that regulates an array of detoxifying and antioxidant defense genes expression in the liver. The objective of this study is to examine whether silymarin alone or in combination with vitamin E and/or curcumin plays a modulatory role against MAPK, STAT3, AKT, Smad-2 and TGF-ß protein expressions that produced apoptotic damage in rat's liver by the administration of carbon tetrachloride (CCl4). The results of the present work revealed that CCl4-induced an elevation of serum alanine aminotransferase (ALT) with concomitant increase in MAPK, STAT3, AKT, Smad-2 and TGF-ß hepatic protein expression, administration of silymarin alone down regulates these expressions. Treatment with vitamin E and/or curcumin along with silymarin produced best results in this concern. On the other hand, Nrf2 protein expression was down regulated by CCl4 whereas concurrent treatment with vitamin E and/or curcumin along with silymarin increased this expression. It was concluded that CCl4-induced protein expression of apoptotic and fibenorgenic factors. Whereas administration of silymarin alone or in combination with vitamin E and/or curcumin plays a modulatory role against the previous aforementioned apoptotic factors expressions. The use of vitamin E and/or curcumin potentiates the anti-apoptotic action of silymarin. So this combination can be used as hepatoprotective agent against other hepatotoxic substances.

Down-Regulation of NFkB, Bax,TGF-β, Smad-2mRNA expression in the Livers of Carbon Tetrachloride Treated Rats using Different Natural Antioxidants

The objective of this study is to examine whether silymarin alone or in combination with chlorogenic acid and/ or melatonin plays a modulatory role against apoptotic damage in rats liver induced by of CCl4. The present work revealed that CCl4 induced elevation of in Bax, Smad, TGF-β and NFkBhepatic mRNA expression, administration of silymarin alone down regulates these expressions. Treatment with chlorogenic acid and/ or melatonin along with silymarin produced best results in this concern. Bcl-2 expression was down regulated by CCl4 whereas concurrent treatment of chlorogenic acid and/ or melatonin along with silymarin increased this expression. On conclusion, the use of chlorogenic acid and/ or melatonin potentiates the anti-apoptotic action of silymarin.