Effects of wearing a mask on oxygenation of subjects with spontaneous breathing during supplementary oxygen through facemask / 生物医学工程学杂志

During the COVID-19 epidemic, our national guidelines have suggested that surgical patients should wear a mask to decrease the potential transmission of COVID-19 in the operating room, as long as the condition allows. However, so far, there is no study to discuss the influence of wearing a mask on the ventilation and blood oxygenation status in patients of spontaneous breathing with supplementary oxygen through an anesthetic facemask. This is a before-after study in the same patient, and 10 healthy volunteers were recruited, by testing the arterial blood gas parameters at key time points before and after oxygen inhalation to evaluate the effects of two different supplementary oxygen methods ('disposable medical mask + anesthetic facemask' and 'anesthetic facemask only') on the oxygenation of subjects. Our data demonstrated whether wearing a disposable medical mask or not could effectively increase the oxygen supply of the subjects compared with the basic value before oxygen inhalation; however, compared with the group without mask, the arterial oxygen partial (PaO

Role of P2X receptors in synthesis and release of IL-1β during oxygen-glucose deprivation in rat hippocampus / 中华麻醉学杂志

Objective To evaluate the role of P2X receptors in the synthesis and release of IL-1β during oxygen-glucose deprivation (OGD) in rat hippocampus. Methods Male SD rats weighing 150-200 g were anesthetized with ether and decapitated. The hippocampi were removed and sagittally sliced (400 μm thick) and placed in artificial cerebrospinal fluid (aCSF) aerated with 95% O2-5% CO2. One hundred and sixty hippocampal slices were randomly divided into 4 groups ( n = 40 each): Ⅰ control group (group C); Ⅱ OGD group; Ⅲ OGD +BBG group; Ⅳ OGD + anti-P2X4 group (group OP). In group C, the hippocampal slices were continously incubated with aCSF aerated with 95% O2-5% CO2 . In group OGD, the hippocampal slices were incubated with glucose-free aCSF and aerated with 95% N2-5%CO2 . In group OGD + BBG, the hippocampal slices were incubated with aCSF containning P2X7 receptor-specific antagonist G (BBG, final concentration 1 μmol/L) and aerated with 95% O2-5% CO2 for 20 min, then exposed to OGD, and BBG (final concentration 1 μ mol/L) was added in glucose-free aCSF. In group OP, the hippocampal slices were incubated with aCSF containning P2X4 receptor antibody (final concentration 1.5 μg/ml) and aerated with 95% O2-5% CO2 for 60 min, then exposed to OGD, and P2X4 receptor antibody (final concentration 1.5 μg/ml) was added in glucose-free aCSF. LDH and IL-1β release was detected before OGD and at 20, 40 and 60 min of OGD. Histological changes were observed using HE staining.Intracellular pro-IL-1β precursor protein expression was detected by Western blot at 60 min of OGD. Results LDH and IL-1β release and expression of intracellular pro-IL-1β precursor protein were signifcantly higher in the other groups than in group C ( P ＜ 0.05 ). Compared with group OGD, LDH and IL- 1 β release was signifcantly decreased, while the expression of intracellular pro-IL-1β precursor protein un-regulated in group OGD + BBG ( P ＜0.05), but no signifcant difference was found in the prarameters mentioned above in group OP ( P ＞ 0.05). Conclusion P2X7 receptor mediates the synthesis and release of IL-1β during OGD in rat hippocampus, but P2X4 receptor does not.

Role of P2X7 receptors in release of glutamate and γ-aminobutyric acid during oxygen-glucose deprivation in rat hippocampus and neuronal synaptosome / 中华麻醉学杂志

Objective To evaluate the role of P2X7 receptors in release of glutamate (Glu) and γ-aminobutyric acid (GABA) during oxygen-glucose deprivation (OGD) in rat hippocampus and neuronal synaptosome.Methods Healthy male SD rats weighing 150-200 g were decapitated. Their hippocampi were isolated and cut into slices 400 μm thick or made into neuronal synaptosomes. The hippocampal slices and neuronal synaptosomes were incubated in artificial cerebro-spinal fluid (aCSF) at 35℃ for 30 min and divided into 3 groups ( n = 32 or 24 each): control group (group C); group OGD and group OGD + BBG (brilliant blue G, a specific P2X7 receptor antagonist). OGD was induced by incubating the slices and synaptosomes in glucose-free aCSF aerated with 95% N2-5% CO2. In group OGD + BBG the slices and synaptosomes were incubated in O2-glucose deprived aCSF containing BBG 1 μmol/L 2 ml. Release of Glu and GABA from hippocampal slices and synaptosomes was determined by HPLC at 0, 20, 40, 60 min of OGD (T1-4). Hippocampal slices were examined with microscope.Results ( 1 ) The release of Glu and GABA from hippocampal slices and synaptosomes were significantly increased after OGD ( P ＜ 0.05). (2) Glu released from hippocampal slices was significantly decreased at T3-4 and Glu released from synaptosomes increased at T2-4 in group OGD + BBG as compared with group OGD ( P ＜ 0.05). (3)GABA released from hippocampal slices was significantly decreased at T4 in group OGD + BBG as compared with group OGD ( P ＜ 0.05). There was no significant difference in GABA released from synaptosomes between group OGD and OGD + BBG (P ＞ 0.05). (4) Microscopic examination showed that OGD induced significant histopathological damage to hippocampal slices which was attenuated by BBG treatment. Conclusion P2X7 receptors mediates the release of Glu and GABA during OGD in rat hippocampus and the P2X7 receptors in glial cells plays a leading role.