PROTECTIVE ROLE OF BACOSIDE A ON BLOOD BRAIN BARRIER INTEGRITY

Abstract

Oxidative stress induced loss of neuronal function with age is related to disruption of the blood brain barrier (BBB)integrity. The protective effect of Bacopa monnieri in combating oxidative stress induced dysfunction of BBB is being studied. We extracted, isolated and quantified bacoside A from bacopa leaf powder. An invivo trial was conducted in rats, which were treated with two doses of Bacoside A (200 and 400 mg/kg BW), through intra-peritoneal route for 7 consecutive days and the efficacy of the treatment was tested by studying the integrity of BBB using Evan’s Blue (EB) dye extravasation, antioxidant enzyme activity and Lipid peroxidation and expression of tight junction (TJ) protein occludin and ROS induced factor Nrf2in the brain. Bacoside A treatment for 7 days resulted in a dose dependent significant (p<0.001) decrease in concentration of EB into the brain indicative of minimum disruption in BBB integrity compared to control rats. Similarly, bacoside A significantly (p<0.001) increased the activity of antioxidant enzymes viz. SOD, catalyse and GPx, with a concomitant significant (p<0.001) decrease in lipid peroxidation in brain. Further, a small dose depended increase in the relative mRNA expression of occludin and Nrf2 was observed in brain of rats treated with bacoside A. Hence, it is concluded that the beneficial effect of Bacoside A in restoring integrity of BBB could be associated with the increased expression TJ protein occludin and ROS induced transporter Nrf2 that might have strengthened the TJ and minimized ROS induced damage of the BBB.