Inhibitory Effect of Bergenin on TLR-4/NF-κB Signal Pathway in Reducing Allergic Rhinitis in Mice

[Objectives]To explore the effect and possible mechanism of bergenin in relieving allergic rhinitis(AR)in mice.[Methods]50 C57/BL6 mice were randomly divided into blank group(n=10),model group(n=10)and high(100 mg/kg),medium(50 mg/kg)and low(25 mg/kg)dose bergenin groups with 10 mice in each group.Except for the blank group,the other mice were sensitized by basic ways combined with attack to replicate the AR model.From the 15th d of modeling(from the second d after the end of the basic modeling),the drug group was given bergenin orally for 15 d,and the blank group and model group were given the same volume of normal saline once a day.24 h after the last establishment of the model,the content of interleukin 4(IL-4),IL-6,TNF-αand IL-1βin nasal lavage fluid and serum of mice in each group was detected by ELISA.The expression of TLR-4,NF-κB and p-NF-κB in nasal mucosa of mice was detected by Western blot.[Results]Compared with the blank group,the content of inflammatory factors IL-4,IL-6,TNF-αand IL-1βin nasal lavage fluid and serum of model group was significantly increased,and the protein expression of TLR-4 and p-NF-κB was significantly increased.After the intervention of bergenin,the content of IL-4,IL-6,TNF-αand IL-1βin nasal lavage fluid and serum and TLR-4 and p-NF-κB protein in tissue was significantly inhibited in bergenin group.[Conclusions]Bergenin can effectively reduce allergic inflammation in AR model mice,and its mechanism may be related to inhibition of inflammation and down-regulation of TLR-4/NF-κB signal pathway.

Proteasome alteration and delayed neuronal death in hippocampal CA1 and dentate gyrus regions following transient cerebral ischemia

BACKGROUND： Proteasome dysfunction has been reported to induce abnormal protein aggregation and cell death. OBJECTIVE： To investigate the effect of proteasome changes on delayed neuronal death in CA1 and dentate gyrus （DG） regions of the rat hippocampus following transient cerebral ischemia. DESIGN, TIME AND SETTING： A randomized, controlled animal experiment. The study was performed at the Department of Biochemistry and Molecular Biology, Norman Bethune Medical College of Jilin University, from September 2006 to May 2008. MATERIALS： Rabbit anti-19S S10B polyclonal antibody was purchased from Bioreagents, USA; propidium iodide and fluorescently-labeled goat anti-rabbit IgG were purchased from Jackson Immunoresearch, USA; hematoxylin and eosin staining solution was purchased from Sigma, USA; LSM 510 confocal microscope was purchased from Zeiss, Germany. METHODS： A total of 40 healthy Wistar rats, male, 4 months old, were randomly divided into sham surgery group （n = 8） and model group （n = 32）. Ischemic models were established in the model group by transient clamping of the bilateral carotid arteries and decreased blood pressure. After 20 minutes of global ischemia, the clamp was removed to allow blood flow for 30 minutes, 4, 24 and 72 hours, respectively, with 8 rats at each time point. The bilateral carotid arteries were not ligated in the sham surgery group. MAIN OUTCOME MEASURES： Neuronal death in the CA1 and DG regions was observed by hematoxylin-eosin staining. Proteasome expression in CA1 and DG region neurons was detected by immunohistochemistry. RESULTS： Hematoxylin-eosin staining showed neuronal death in the CA1 region alone at 72 hours of reperfusion following ischemia. In comparison to the sham surgery group, a significant decrease in proteasome expression was observed, by immunohistochemistry, in the CA1 and DG regions in the model group, following 30 minutes, 4, 24, and 72 hours of reperfusion （P 〈 0.01）. After 72 hours of reperfusion following ischemia, proteasome expression had almost completely disappeared in the CA1 region. In contrast, neurons of the DG region showed minimized proteasome expression at 24 hours, with a slight increase at 72 hours （P 〈 0.01）. CONCLUSION： The alteration of proteasome following ischemia/reperfusion in the neurons of hippocampal CA1 and DG regions reduces the ability of cells to degrade abnormal protein, which may be an important factor resulting in delayed neuronal death following transient cerebral ischemia.

Protein aggregation in association with delayed neuronal death in rat model of brain ischemia

To investigate the relationship between protein aggregation and delayed neuronal death,we adopted rat models of 20 min ischemia.Brain ischemia was produced using the 2-vessel occlusion(2VO)model in rats Light microscopy,transmission electronic microscopy and Western blot analysis were performed for morphological analysis of neurons,and protein detection.The results showed delayed neuronal death took place at 72 h after ischemia-reperfusion,protein aggregates formed at 4 h after reperfusion and reached the peak at 24 h after reper-fusion,and Western blot analysis was consistent with transmission electronic microscopy.We conclude that protein aggregation is one of the important factors leading to delayed neuronal death.