ABSTRACT
ObjectiveTo investigate the protective effect of the extract of Liuwei Dihuangwan （LW） on mitochondrial damage in the Alzheimer's disease （AD） model of Caenorhabditis elegans （C. elegans）. MethodC. elegans transfected with human β-amyloid protein （Aβ） 1-42 gene was used as an AD model. The rats were divided into blank group， model group， metformin group （50 mmol·L-1）， and low， medium， and high dose （1.04， 2.08， 4.16 g·kg-1） LW groups. Behavioral methods were used to observe the sensitivity of 5-hydroxytryptamine （5-HT） in nematodes. Western blot was used to detect the expression of Aβ in nematodes. Total ATP content in nematodes was detected by the adenine nucleoside triphosphate （ATP） kit， and mitochondrial membrane potential was detected by the JC-1 method. In addition， the mRNA expression of Aβ expression gene （Amy-1）， superoxide dismutase-1 （SOD-1）， mitochondrial transcription factor A homologous gene-5 （HMG-5）， mitochondrial power-associated protein 1 （DRP1）， and mitochondrial mitoprotein 1 （FIS1） was detected by real-time fluorescence quantitative polymerase chain reaction （RT-PCR）. ResultThe extract of LW could reduce the hypersensitivity of the AD model of nematodes to exogenous 5-HT （P<0.05） and delay the AD-like pathological characteristics of hypersensitivity to exogenous 5-HT caused by toxicity from overexpression of Aβ in neurons of the AD model of nematodes. Compared with the blank group， in the model group， the mRNA expression of Aβ protein and Amy-1 increased （P<0.01）， and the mRNA expression of SOD-1 and HMG-5 decreased （P<0.01）. The mRNA expression of DRP1 and FIS1 increased （P<0.01）， and the level of mitochondrial membrane potential decreased （P<0.05）. The content of ATP decreased （P<0.01）. Compared with the model group， in the positive medicine group and medium and high dose LW groups， the mRNA expression of Aβ protein and Amy-1 decreased （P<0.05，P<0.01）， and the mRNA expression of SOD-1 and HMG-5 increased （P<0.01）. The mRNA expression of DRP1 decreased （P<0.05，P<0.01）， and that of FIS1 decreased （P<0.01）. The level of mitochondrial membrane potential increased （P<0.01）， and the content of ATP increased （P<0.05，P<0.01）. ConclusionThe extract of LW may enhance the antioxidant ability of mitochondria， protect mitochondrial DNA， reduce the fragmentation of mitochondrial division， repair the damaged mitochondria， adjust the mitochondrial membrane potential， restore the level of neuronal ATP， and reduce the neuronal damage caused by Aβ deposition.
ABSTRACT
Objective:To study the effect of total flavonoids of Rhizoma Drynariae on learning and memory impairment mice induced by sodium nitrite. Methods:75 mice were divided into blank group, model group, Kangnaoshuai capsule group, Rhizoma Drynariae total flavonoids group and Rhizoma Drynariae total flavonoids+inhibitor group according to the random number table method, with 15 mice in each group. The Kangnaoshui Capsule group was administered with Kangnaoshui Capsule 585 mg/kg, the Rhizoma Drynariae total flavonoids group was administered with the Rhizoma Drynariae total flavonoids 97.5 mg/kg, the Rhizoma Drynariae total flavonoids group and the inhibitor group were administered with the Rhizoma Drynariae total flavonoids by intragastric administration 97.5 mg/kg, and intraperitoneal injection of 0.072 mg/kg ICI182780 for 21 days, once a day. The model was established on the 22nd day. Except for the blank group, the other mice were injected with sodium nitrite intraperitoneally to replicate the mice model with impaired learning and memory capability. The learning and memory capabilit of mice were detected with water maze method, and the estrogen receptor in hippocampus was detected by immunohistochemistry β (estrogen receptor β, ERβ). The expression of ERβ in hippocampus and the expression of phosphorylated P38 (P-P38) and the protein contents of B-cell lymphoma-2 (Bcl-2), Bcl-2 associated death promoter (Bad) and Caspase-3 in the apoptotic system was detected by Western blot. The kit was used to detect MDA,SOD and NO protein content in hippocampus. Results:The latency of Rhizoma Drynariae total flavonoids group was significantly shorter than the model group, the number of crossing platform and the residence time in the target quadrant were significantly increased ( P<0.01); The expression of ERβ Protein in mice hippocampus (0.371 ± 0.010 vs. 0.124 ± 0.009), Bcl-2 protein (1.146 ± 0.028 vs. 0.726 ± 0.016) and the contents of SOD [(153.657 ± 6.385) U/mg vs. (67.719±5.845) U/mg] increased significantly ( P<0.01); The expression of P-P38/P38 protein (0.412 ± 0.043 vs.0.806 ± 0.069), Bad protein (0.421 ± 0.010 vs.0.633 ± 0.010), Caspase-3 protein (0.923 ± 0.042 vs.1.437 ± 0.033), and the content of MDA [(8.669 ± 0.662) nmol/mg vs. (11.772 ± 1.054) nmol/mg] and NO [(4.259 ± 0.225) nmol/mg vs. (10.805 ± 0.415) nmol/mg] decreased significantly ( P<0.01). In addition, ER blocker can antagonize the above recovery and improvement effects of Rhizoma Drynariae total flavonoids group. Conclusion:Rhizoma Drynariae total flavonoids can regulate memory impairment, inhibit neuronal apoptosis and reduce oxidative stress in sodium nitrite model mice through ER-P38/MAPK signal pathway.