Effect of borneol combined with astragaloside IV and Panax notoginseng saponins on transporter proteins of blood-brain barrier after cerebral ischemia-reperfusion / 中草药

ABSTRACT

Objective: To investigate the effects of borneol combined with astragaloside IV (AST IV) and Panax notoginseng saponins (PNS) on promoting the active components into the brain and anti-brain injury through the regulation of transporter proteins of blood-brain barrier (BBB) in the state of cerebral ischemia-reperfusion. Methods: Focal cerebral ischemia-reperfusion model in rats was established, borneol, AST IV, PNS and the combination were administered by gavage, brain infarction rate was evaluated by 2,3,5-triphenyl tetrazolium chloride (TTC) staining, the expressions of efflux proteins such as p-glycoprotein (P-gp), multidrug resistance protein (MRP)-1, MRP-2, MRP-4, MRP-5 and uptake proteins such as organic cation transporter (OCT)-3, organicanion transporting polypep-tides (OATP)-2 in brain tissues were detected by Western blotting. The expressions of multidrug resistance (MDR) such as mdr1a, mdr1b and mrp-1, mrp-2, mrp-4, mrp-5 mRNA in brain tissues were determined by real-time PCR method. Results: The results of TTC staining showed that brain infarct was found after cerebral ischemia-reperfusion. Each drug could significantly reduce brain infarction volume and decrease infarction rate, and the effect of AST IV + PNS was better than that of AST IV and PNS alone, the effect of borneol + AST IV + PNS was better than that of single drug and AST IV + PNS. The results of major efflux proteins and genes detection showed that the protein expressions of P-gp, MRP-1, MRP 2, MRP-4, and MRP-5 were significantly increased in rats after cerebral ischemia-reperfusion. Borneol could significantly down-regulate the expressions of P-gp, MRP-2, MRP-4 proteins, PNS could significantly down-regulate the levels of MRP-4, MRP-5 proteins; AST IV, AST IV + PNS and borneol + AST IV + PNS could significantly down-regulate P-gp, MRP-2, MRP-4, MRP-5 proteins, and the effects of borneol + AST IV + PNS were significantly better than those of single drug and AST IV + PNS; The effects of AST IV + PNS were significantly better than those of AST IV or PNS alone. The results of gene expressions were similar to those of protein expression. The results of major uptake proteins showed that the expression of OCT-3 protein did not change significantly in the model group and drug groups after cerebral ischemia-reperfusion; However, the expression of OATP-2 protein was significantly decreased in the model group. PNS, AST IV + PNS and borneol + AST IV + PNS could significantly up-regulate the expression of OATP-2 protein; Furthermore, the effect of borneol + AST IV + PNS was significantly greater than that of single drug and AST IV + PNS, and the effect of AST IV + PNS was significantly greater than that of AST IV and PNS alone. Conclusion: After cerebral ischemia-reperfusion, brain tissues were damaged, the expressions of major efflux proteins and genes on BBB were significantly increased, while the expression of uptake protein such as OATP-2 was significantly decreased. Borneol combined with AST IV and PNS can enhance the effect of anti-ischemic brain injury, which may be related to the down-regulations of the expressions of efflux proteins such as P-gp, MRP-2, MRP-4, MRP-5 and corresponding genes in BBB, as well as the up-regulation of the expression of uptake proteins such as OATP-2, thus promoting the absorption and the enrichment of borneol, AST IV and the effective components of PNS in brain tissues, playing a better role in pharmacology.