RESUMO
Objective:To evaluate the role of hypoxia-inducible factor-1α (HIF-1α)/Bcl-2/E1B 19-kDa interacting protein 3 (BNIP3) signaling pathway in dexmedetomidine-induced reduction of myocardial ischemia-reperfusion (I/R)-induced brain injury in mice.Methods:Sixty clean-grade healthy male C57BL/6 mice, aged 8-10 weeks, weighting 20-30 g, were divided into 5 groups ( n=12 each) using a random number table method: sham operation group (S group), myocardial I/R group (IR group), myocardial I/R plus dexmedetomidine group (IRD group), myocardial I/R plus HIF-1α inhibitor 2ME2 group (IR-M group), and myocardial I/R plus dexmedetomidine plus HIF-1α inhibitor 2ME2 group (IRD-M group). The myocardial I/R-induced brain injury was produced by ligating the left anterior descending coronary artery for 30 min followed by 2 h of reperfusion in anesthetized mice.Dexmedetomidine 50 μg/kg was intraperitoneally injected at 5 min before ischemia in IRD group and IRD-M group.In IR-M and IRD-M groups, 2ME2 15 mg/kg was intraperitoneally injected at 5 min before ischemia.Blood samples were collected from the thoracic aorta at 2 h of reperfusion to measure the serum S-100β protein and neuron-specific enolase (NSE) concentrations.The animals were then sacrificed, brains were removed and hippocampi were obtained for determination of the apoptosis index (by TUNEL method) and expression of HIF-1α, BNIP3, Beclin-1, microtubule-associated protein 1 light chain 3 (LC3) and phosphorylated Tau protein (p-Tau) (by Western blot) and for microscopic examination of the pathological changes in hippocampal CA1 region.LC3Ⅱ/Ⅰ ratio was calculated. Results:Compared with group S, the concentrations of serum S-100β protein and NSE and apoptosis index of hippocampal neurons were significantly increased, the expression of HIF-1α, BNIP3, Beclin-1 and p-Tau was up-regulated, LC3Ⅱ/Ⅰ ratio was increased ( P<0.05), and the pathological changes in hippocampal CA1 region were aggravated in group IR.Compared with group IR, the concentrations of serum S-100β protein and NSE and apoptosis index of hippocampal neurons were significantly decreased, the expression of HIF-1α, BNIP3 and Beclin-1 was up-regulated, the expression of p-Tau was down-regulated, and LC3Ⅱ/Ⅰ ratio was increased ( P<0.05), and the pathological changes in hippocampal CA1 region were significantly attenuated in group IRD.Compared with group IRD, the concentrations of serum S-100β protein and NSE and apoptosis index of hippocampal neurons were significantly increased, the expression of p-Tau was up-regulated, the expression of HIF-1α, BNIP3 and Beclin-1 was down-regulated, LC3Ⅱ/Ⅰ ratio was decreased ( P<0.05), and the pathological changes in hippocampal CA1 region were aggravated in IR-M and IRD-M groups. Conclusions:HIF-1α/BNIP3 signaling pathway is involved in dexmedetomidine-induced reduction of myocardial I/R-induced brain injury in mice.
RESUMO
Objective:To establish a BALB/c mouse model of Echinococcus granulosus allergy and investigate the role of lymphocyte subsets in Echinococcus granulosus-induced sensitization. Methods:Echinococcus granulosus was isolated from the liver of sheep naturally infected with Echinococcus granulosus and cultured for 40 d. BALB/c mice were intraperitoneally injected with 50 microcapsules and sensitized by intraperitoneal injection of 0.1 ml/10 g of larval Echinococcus granulosus capsule six months after infection. According to the symptom scores 1 h after sensitization, these mice were divided into two groups: non-sensitized group ( n=6) and sensitized group ( n=6). The mice ( n=6) in control group were injected with sterile saline. Blood sample was collected from the angular vein of each mouse. Flow cytometry was used to detect B cells, NK cells and CD3 +/CD4 +/CD8 + T cells. Cytometric bead array was used to measure IL-4, IL-6 and IL-13. Results:The percentage of B cells was significantly higher in the non-sensitized group than in the control group ( P<0.001), but no significant difference was observed between the sensitized group and the control group. Compared with the non-sensitized group, the percentage of B cells in the sensitized group decreased significantly ( P<0.01). Compared with the control group, the percentages of NK cells in the non-sensitized group and the sensitized group decreased significantly ( P<0.001 and P<0.01). Compared with the non-sensitized group, the percentage of NK cells in the sensitized group increased significantly ( P<0.05). Compared with the control group, the percentage of CD3 + and CD4 + T cells in the non-sensitized group decreased significantly ( P<0.05), while the percentage of CD8 + T cells increased significantly ( P<0.01). Compared with the control group, the percentage of CD3 + and CD4 + T cells in the sensitized group increased significantly ( P<0.05 and P<0.001), while no significant change in the percentage of CD8 + T cells was detected. Compared with the non-sensitized group, the percentage of CD3 + and CD4 + T cells in the sensitized group increased significantly ( P<0.05), while the percentage of CD8 + T cells decreased significantly ( P<0.01). The levels of IL-4, IL-6 and IL-13 were significantly higher in the non-sensitized group than in the control group ( P<0.001). Compared with the control group, the sensitized group showed increased IL-4 ( P>0.05), significantly increased IL-6 ( P<0.01) and decreased IL-13 ( P>0.05). The levels of IL-4, IL-6 and IL-13 in the sensitized group were significantly lower than those in the non-sensitized group ( P<0.001). Conclusions:The BALB/c mouse model of allergy induced by larval Echinococcus granulosus was successfully established. This study proved that the humoral immune response induced by Th2 cells played an important role in Echinococcus granulosus-induced sensitization, which provides an important scientific basis for establishing a prevention and treatment strategy for patients with anaphylactic shock caused by extravasation of Echinococcus granulosus fluid.