Protective Effects Of Berberine On Hydrogen Peroxide And Amyloid Beta (25-35)-induced Injury In Rat Pheochromocytoma Cells

Berberine is an isoquinoline alkaloid with a long history of medicinal used in both Ayurvedic and Chinese medicine. The berberine alkaloid can be found in the roots, rhizomes, and stem bark of the plants, such as Hydrastis canadensis (goldenseal), Coptis chinensis (Coptis or goldenthread). These medicinal plants have been used as folk medicine in treatment of jaundice, dysentery, hypertension, inflammation and liver diseases.Recently, Liu et al also reported the cognitive function was greatly improved,with the score of the behavioral syndromes scale for dementia (BSSD) and other tests in probable Alzheimer's disease (PAD) and probable vascular dementia (PVD) significantly higher than those before the administration of berberine in high risking people of aged dementia. Wu et al reported that berberine reduced the generation of lipid peroxide in oxygen/glucose deprived cortical cultures.With the aging of society, Alzheimer's disease (AD) is the most common form of adult onset dementia. The major hurdle in understanding AD is a lack of knowledge about the eitology and pathogenesis of selective death. AD is a multineurotransmitter deficiency disease. In recent years, considerable data have accrued indicating that the brain in AD is under increased oxidative stress and selective neuron loss and shrinkage, synapse loss and these may have a role in the pathogenesis of neuron degeneration and death in this disordor.The rat pheochromocytoma line PC12 cell, which displays phenotypic characteristics of both adrenal chromaffin cells and sympathetic neurons is a reliable system for exploring neuroprotective drugs and widely used as the proper model system for the investigation of neurodegenerative disorders. In this study, we investigated the protective effects and mechanism of berberine on the PC12 cells.1. Protective effects and mechanism of berberine on H₂O₂ -induced cytotoxicity in rat pheochromocytoma cellsIn this study, we investigated the protective effects of berberine on the cell death, the generation of reactive oxygen species (ROS) and elevation of intracellular calcium ([Ca²⁺]i) induced by hydrogen peroxide (H₂O₂) in cultured rat pheochromocytoma (PC12) cells. PC12 cells treated with H₂O₂ (150μM) for 6 h underwent cell death as determined by 3-[4.5-dimemethylthiazol-z-y']-2, 5-diphenyltetrazolium bromide (MTT) evaluation. Meanwhile, the level of lipid peroxidation and antioxidant enzyme activities were measured by assay kits and the apoptotic death was tested by 4',6-diamidine-2'phenylindole (DAPI) nuclei staining. Pretreatment with berberine (0.01 -10μM) for 24 h prior to H₂O₂ exposure significantly elevated the cell survival and antioxidant enzyme activities and decreased the level of MDA. Preincubation with berberine also significantly prevented the cells from H₂O₂-induced apoptosis, ROS generation and [Ca²⁺]i. These results suggest that berberine has protective effects against free radical-induced cell toxicity in a dose-dependent manner, which has therapeutic potential in a treatment of oxidative damage-derived neurodegenerative disorders.2. Protective effects and mechanism of berberine on Aβ(25-35) -induced cytotoxicity in rat pheochromocytoma cellsThe deposition ofβ-amyloid protein (Aβ) a 39-43 amino acid peptide, in the brain is pathological hallmarks of AD. We examined the protective effects of berberine on the cell death, the generation of ROS, [Ca²⁺]i and caspase-3 expression induced by Aβ(25-35) in rat PC12 cells. PC12 cells treated with Aβ(25μM) for 36 h underwent cell death as determined by MTT evaluation. The present study was also conducted by measuring the antioxidant enzyme activities. The apoptotic death has been tested by DAPI nuclei staining. Pretreatment with berberine (0.01 -10μM) for 24 h prior to Aβexposure significantly elevated the cell survival and antioxidant enzyme activities. Preincubation with berberine also significantly prevented the cells from Aβ-induced apoptosis, ROS generation and [Ca²⁺]i. These results suggest that berberine has protective effect on Aβ-induced PC12 cell death, and its effect may be through antioxidative property, prevented [Ca²⁺]i and decreased expression of caspase-3 in a dose-dependent manner.These results suggest that free radicals and Aβare involved in the neurodegenerative disorders such as AD and berberine has protective effects against free radical and Aβ-induced cell toxicity in a dose-dependent manner, which has therapeutic potential in a treatment of AD.