ABSTRACT
This study was to investigate the effect of peoniflorin on the expressions of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream signal molecules in the hippocampus of Alzheimer's disease (AD) rats for exploring the mechanism of peoniflorin protecting hippocampal neurons. AD model rats were established by bilateral intrahippocampal injection of beta-amyloid(1-42) (Abeta(1-42)) and divided randomly into 3 groups: AD model group, peoniflorin low-dose (15 mg x kg(-1)) group and peoniflorin high-dose (30 mg x kg(-1)) group. The vehicle control rats were given bilateral intrahippocampal injection of solvent with the same volume. After peoniflorin or saline was administered (ip) once daily for 14 days, the hippocampuses of all animals were taken out for measuring the expressions of Nrf2, heme oxygenase-1 (HO-1) and gamma-glutamylcysteine synthethase (gamma-GCS) mRNA by reverse transcription PCR, determining the contents of glutathione (GSH), malondialdehyde (MDA) and carbonyl protein (CP) using colorimetric method, and for assaying the expressions of neuronal apoptosis inhibitory protein (NAIP) and Caspase-3 by immunohistochemical staining method. The results showed that peoniflorin markedly increased the expressions of Nrf2, HO-1 and gamma-GCS mRNA, enhanced the level of GSH and decreased the contents of MDA and CP in the hippocampus, as compared with the model group. Peoniflorin also improved the NAIP expression and reduced the Caspase-3 expression in the hippocampus neurons. In conclusion, peoniflorin protects against the Abeta(1-42)-mediated oxidative stress and hippocampal neuron injury in AD rats by activating the Nrf2/ARE pathway.
ABSTRACT
<p><b>OBJECTIVE</b>To study the mechanisms of Danggui Shaoyao San (DSS) on Alzheimer's diseases (AD) focusing on anti-inflammation.</p><p><b>METHOD</b>AD rats were established by intrahippocampal bilateral injection of Abeta1-42 protein. The AD rats were randomly divided into three groups: AD model group, DSS high-dose group, DSS low-dose group. Vehicle group rats were intrahippocampal bilateral injection of solvent with the same dose. The learning ability and memory of rats was investigated in step-down passive avoidance test and Morris water maze test, expression of IL-1beta, IL-6, TNF-alpha mRNA were observed by reverse transcriptase PCR (RT-PCR), levels of NO was measured by colorimetric method and neuron apoptosis in the hippocampus was investigated by tag method of TdT-mediated end-labeling of fragmented DNA (TUNEL).</p><p><b>RESULT</b>DSS significantly reduced the escape latency and increased the time that rats spent in the target quadrant in Morris water maze test, shortened the responsive latency and decreased the error numbers in step-down passive avoidance test, reduced the expression of the IL-1beta, IL-6, TNF-alpha mRNA, and the level of the NO depressed the neuron apoptosis in the hippocampus.</p><p><b>CONCLUSION</b>DSS improving cognition of the rats might be related to attenuate inflammatory reaction and reduce cell apoptosis in the hippocampus.</p>