ABSTRACT
OBJECTIVE To study the ameliorative effect and potential mechanism of curcumin on diabetes model rats with depression based on cAMP response element binding protein （CREB）/brain-derived neurotrophic factor （BDNF） signaling pathway. METHODS The diabetes model rat with depression was established by high fat and high sugar diet+intraperitoneal injection of streptozotocin+chronic unpredictable stress-induced depression. The successfully modeled rats were randomly divided into model group， positive control group （0.18 g/kg metformin and 1.8 mg/kg fluoxetine， gavage）， curcumin low-dose and high-dose groups （30， 60 mg/kg， gavage） and curcumin high-dose+CREB inhibitor group [60 mg/kg curcumin （gavage）+5 mg/kg CREB inhibitor 666-15 （intraperitoneal injection）]， with 12 rats in each group. Another 12 healthy rats were selected as the normal group. Each group was given a corresponding intervention for 4 weeks， the fasting blood glucose level of rats was detected， and the depression of rats was assessed. The levels of corticosterone （CORT） and inflammatory factors [tumor necrosis factor-α （TNF-α）， interleukin- 1β （IL-1β）， IL-6] in serum， and the levels of norepinephrine （NE） and 5-hydroxytryptamine （5-HT） in hippocampal tissue were determined. The pathological changes and neuronal apoptosis were observed in the hippocampal tissue of rats in each group； the expression levels of CREB， BDNF mRNA and protein in hippocampal tissue were detected. RESULTS Compared with the normal group， the hippocampal tissue of rats in the model group was severely damaged， and neurons were scattered， while the fasting blood glucose， the forced swimming immobility time， the tail suspension immobility time， serum levels of CORT， TNF-α， IL-1β and IL-6， and neuron apoptosis indexes were all increased or prolonged significantly （P＜0.05）. The levels of NE and 5-HT， the number of surviving neurons， and the expression levels of CREB and BDNF mRNA and protein in hippocampal tissue were decreased significantly （P＜0.05）. Compared with the 的model group， the damage to hippocampal tissue was relieved in the positive control group and curcumin groups， while the above indexes were improved significantly （P＜0.05）. The improvement effect of curcumin high-dose group was better than that of curcumin low-dose group （P＜0.05）. CREB inhibitor could significantly reverse the ameliorative effect of high-dose curcumin on the model rats （P＜0.05）. CONCLUSIONS Curcumin can improve the depression of diabetes model rats with depression， and relieve neuronal damage and inflammatory response， the mechanism of which may be associated with activating CREB/BDNF signaling pathway.
ABSTRACT
OBJECTIVE To study the neuroprotective effects of Shenzao jianna o oral liquid （SZJN）on Alzheimer ’s disease （AD）model mice and its mechanism. METHODS The mice were randomly divided into sham operation group ，model group ， Donepezil hydrochloride tablet group （0.65 mg/kg），SZJN low-dose ，medium-dose and high-dose groups （0.3，1.5 and 7.5 g/kg， calculated by crude drug quantity ），with 12 mice in each group ，half male and half female. Each group was given relevant medicine（intragastric administration of water at constant volume in sham operation group and model group ），twice a day ，for consecutive 28 d. On the 15th day of administration ，intracerebroventricular injection of β-amyloid 1-42（Aβ1-42）combined with intraperitoneal injection of scopolamine hydrobromide were used to induce AD model. Morris water maze was used to detect the learning and memory ability of mice. HE staining and Nissl staining were used to evaluate the pathological changes of brain tissue in mice. The levels of MDA and SOD in brain tissue of mice were detected. The phosphorylation level of cyclic adenosine monophosphate response element binding protein （CREB） and expression of brain-derived neurotrophic factor （BDNF） in hippocampal tissues were detected by Western blot. RESULTS Compared with sham operation group ，the escape latency of the model group was significantly prolonged ，and the number of crossing the platform and the percentage of residence time in the target quadrant were significantly reduced （P＜0.01）. The level of SOD in brain tissue ，the phosphorylation level of CREB and the expression level of BDNF in hippocampus decreased significantly （P＜0.01），while the level of MDA increased significantly （P＜ 0.01）. In hippocampal CA 1 area and cortical tissue ，nerve cells showed significantly decreased number ，the disordered arrangement and large gap ；the shape of nucleus was irregular and deeply stained ，and Nissl body was blurred ，loosely arranged and the number decreased. Compared with model group ，the escape latency of mice in each dose group of SZJN was significantly shortened ，and the times of crossing the platform and the percentage of residence time in the target quadrant were significantly jing- increased（P＜0.01）. Above indexes of brain tissue in mice were reversed sig nificantly in SZJN high-dose group （P＜0.01），and pathological damage of brain tiss ue was improved. CONCLUSIONS SZJN can significantly improve the learning and memory ability of AD model mice ，and alleviate the pathological injury and oxidative stress of brain tissue ，which may be related to the activation of CREB/BDNF signaling pathway.