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Objective:To explore the protective effect and underlying mechanism of hyperbaric oxygen (HBO) on delayed encephalopathy after carbon monoxide poisoning (DEACMP) in mice.Methods:Totally 225 adult male Kunming mice were selected to establish CO poisoning model via intraperitoneal injection carbon monoxide (CO), and were randomly divided into the air control group, CO poisoning group, and HBO group. Each group was further divided into five time points group, that was 1, 3, 7, 14 and 21 d. The mice in the air control group were injected intraperitoneally with the same amount of air, and the HBO group received HBO treatment at the same time every day. DEACMP mice model was screened by behaviors using the open field test, new object recognition test and nesting test, and the content of myelin basic protein (MBP) were assayed. The mouse brain tissue and mitochondrial were prepared and malonialdehyde (MDA) and adenosine triphosphate (ATP) content were measured with ultraviolet spectrophotometer. MBP content in brain tissue and cytochrome C (CytC) content in the mitochondrial were measured by ELISA. The mitochondria membrane potential (MMP) was measured by flow cytometry.Results:Compared with the air control group, the content of carboxyhemoglobin (COHB) in blood increased significantly and the content of MBP in brain tissue decreased significantly in CO poisoning mice. CO poisoning mice showed motor ability and cognitive dysfunction. Compared with the air control group, the contents of MMP, CytC and ATP were significantly decreased ( P<0.01) in the CO poisoning group; while the MDA content was significantly increased ( P<0.01). Compared with the CO poisoning group, mice behaviors were improved significantly ( P<0.05), the content of MBP, MMP, CytC and ATP were increased ( P<0.05), while the MDA content decreased significantly ( P<0.01) in the HBO group. Conclusions:The abnormal mitochondrial function might be closely related to the occurrence and development of DEACMP, and HBO therapy plays an effective role in preventing and treating the DEACMP mice model via the mitochondrial pathway.
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Aim To study the effect of cyclosporin A and tetrand ri ne on P-glycoprotein (P-gp)of bovine brain capillary endothelial cell. M ethods The fluorescent dye, rhodamine-123 (Rh-123) was used to evaluate t he functional activity of the P-glycoprotein (P-gp) efflux transport system in primary cultured bovine brain capillary endothelial cell (BCEC) monolayer. Results Rhodamine-123 accumulation was increased significantly in monola yer treated with the P-gp modifying agent, cyclosporin A and tetrandrine. Conclusion The observation suggests that this Rh-123 method is sens itive, stable to evaluate the function of P-gp of blood-brain barrier (BBB). R h-123 accumulation is also increased by tetrandrine in dose-dependent manner.
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The mdr 1-type P-glycoprotein can confer multidrug resistance to tumor cells by actively pumping a wide variety of drugs from the cells. To counteract this drug resistance, P-glycoprotein-blocking agents are currently administered to patient during chemotherapy. However, this may also affect the normal physiological functions of the mdr 1-type P-glycoprotein. The P-gp is a transmembrane efflux transporter found on the luminal side of the capillary cells that comprise the blood-brain barrier. Recent insights recognize P-glycoprotein, as an important element of the blood-brain barrier (BBB), play an important role for mdr 1a P-glycoprotein in the blood-brain barrier. Studies in mice, which lack P-gp in the BBB 〔mdr1a (-/-) mice〕, have contributed significantly to these insights. In addition, the potential of new therapeutic approaches in the near future as well as their limitations will be clearified.