Effect of Albiziae Flos and Polygalae Radix Alone and Their Combination on Depression-like Behavior and CREB and NOX2 Expression in Hippocampus of Chronic Unpredictable Stress-induced Rats / 中国实验方剂学杂志

ABSTRACT

Objective:To observe the effects of Albiziae Flos （AF） and Polygalae Radix （PR） alone and their combination on the improvement of depression-like behavior in rats with chronic unpredictable stress （CUS） as well as on hippocampal ultrastructure and the expression of cyclic adenosine monophosphate response element binding protein （CREB） and nicotinamide adenine dinucleotide phosphate oxidase 2 （NOX2）， to explore their action mechanisms. Method:Seventy-two Wistar rats were randomly divided into the normal group， model group， AF group， PR group， AF-PR group， and fluoxetine group. Rats in all groups except for the normal group were exposed to CUS and separated feeding to induce depression. Since the first day of modeling， rats in the AF group， PR group， AF-PR group were provided with the corresponding decoction containing 1.05 g·kg^-1 total crude drug by gavage， the ones in the fluoxetine group with 2.1 mg·kg^-1 fluoxetine hydrochloride aqueous solution， and those in the normal group and model group with the distilled water， for 28 successive days. The open field test and forced swimming test were performed 1 d before modeling and 7， 14， 21， 28 d after modeling， respectively. The morphological changes in hippocampus were observed under an electron microscope on the 28^th day. The superoxide dismutase （SOD） and malondialdehyde （MDA） levels in hippocampus were detected by ultraviolet spectrophotometry， and the expression levels of CREB and NOX2 were detected by real-time polymerase chain reaction （Real-time PCR） and Western blot. Result:The behavioral experiment results showed that the number of horizontal activities and sugar water consumption in the model group declined as compared with those in the normal group， while the immobility time in the forced swimming test was prolonged （<italic>P</italic><0.05， <italic>P</italic><0.01）. Compared with the model group， the AF group， PR group， and AF-PR group exhibited elevated number of horizontal activities， increased sugar water consumption but shortened immobility time in the forced swimming test （<italic>P</italic><0.05， <italic>P</italic><0.01）. Compared with the AF group or PR group， the AF-PR group showed significantly different behavioral indexes （<italic>P</italic><0.05）. Morphological results showed that the mitochondria of the model group were obviously swollen and the ultrastructure of the hippocampus was destroyed. By contrast， the hippocampal ultrastructure in each administration group was close to normal. The comparison with the normal group revealed that the activity of SOD in the hippocampus of the model group was significantly reduced， whereas the content of MDA was elevated （<italic>P</italic><0.01）. Compared with the model group， the AF group， PR group， and AF-PR group displayed increased activity of SOD and decreased content of MDA in the hippocampal tissues （<italic>P</italic><0.05， <italic>P</italic><0.01）. Compared with AF or PR alone， the herbal pair AF-PR resulted in significant differences in the above-mentioned indexes （<italic>P</italic><0.05， <italic>P</italic><0.01）. The results of Real-time PCR and Western blot demonstrated that NOX2 expression in the hippocampus of the model group was up-regulated in comparison with that in the normal group， while the CREB expression was down-regulated （<italic>P</italic><0.05， <italic>P</italic><0.01）. Compared with the model group， the AF group， PR group， and AF-PR group all showed diminished NOX2 expression but elevated CREB expression in the hippocampal tissues （<italic>P</italic><0.05， <italic>P</italic><0.01）. The protein expression levels of NOX2 and CREB in the AF group or PR group were significantly different from those in the AF-PR group （<italic>P</italic><0.01）. Conclusion:AF and PR alone and their combination improve the depression-like behavior of rats exposed to CUS， which may be related to the reduction of oxidative stress， the up-regulation of CREB expression， and the down-regulation of NOX2 expression in hippocampus.