ABSTRACT
Objective:To investigate the effects of artesunate ( ART ) on neuronal apoptosis, inflammatory response after stroke in rats and microglia polarization.Methods:(1)Animal experiment: twenty-seven male SD rats of SPF grade were divided into sham operation group, model group and ART treatment group according to the random number table method, with 9 rats in each group.Rats in the model group and ART treatment group were used to establish a stroke model by middle cerebral artery occlusion (MCAO). And rats in the ART treatment group were intraperitoneally injected with ART (25 mg/kg) once a day for three days before modeling, while the rats in sham operation group and the model group were injected with the same amount of solvent.And 24 h after the modeling, TTC staining was used to evaluate the volume of cerebral infarction, Western blot was used to detect the expression of Bcl2 in the infarct area, penumbra and hippocampus, TUNEL method was used to detect neuronal apoptosis, and tissue immunofluorescence was used to observe the expression of tumor necrosis factor-α(TNF-α) in the penumbra region of cerebral cortex.(2)Cell experiments: microglia BV2 were cultured and divided into control group, oxygen-glucose deprivation/reoxygenation group, oxygen-glucose deprivation/reoxygenation + 0.05 μmol/L ART group, oxygen-glucose deprivation/reoxygenation + 0.1 μmol/L ART group and oxygen-glucose deprivation/reoxygenation + 0.5 μmol/L ART group.The levels of inflammatory factors interleukin-6(IL-6), interleukin-1β(IL-1β) and TNF-α were detected by qRT-PCR, the expressions of M2 type microglia marker protein CD206 and ARG1 were detected by Western blot, the BV2 cell medium after treatment in each of the above groups was collected as conditioned medium to culture HT22 hippocampal neuron cells and cell activity was measured by CCK8 method.GraphPad Prism 7 software was used for data analysis.One-way ANOVA was used for comparison of differences among multiple groups, and LSD was used for further two-by-two comparisons.Results:(1)Animal experiment results: TTC staining results showed that the percentage of cerebral infarction volume in the ART treatment group was smaller than that in the model group ((23.09±8.51)%, (39.63±5.71)%, t=33.93, P<0.01). The results of TUNEL staining showed that the number of apoptotic cells in the model group and ART treatment group was higher than that in the sham operation group ((638.90±177.82)cells/mm 2, (72.75±13.21) cells/mm 2, (16.16±2.73) cells/mm 2, both P<0.05), and the number of apoptotic cells in the ART treatment group was lower than that in the model group ( P<0.05). Western blot results showed that the levels of Bcl2 protein in penumbra and infarct area of the model group were both lower than those in sham group(both P<0.05). The levels of Bcl2 protein in penumbra, the hippocampus and infarcted area of the ART treatment group were significantly lower than those of the model group(all P<0.05). The results of tissue immunofluorescence showed that the fluorescence intensities of TNF-α in the model group and ART treatment group were higher than those in the sham group (all P<0.05), while the fluorescence intensity of TNF-α in the ART treatment group was lower than that in the model group ( P<0.05). (2)Cell experiment: qRT-PCR results showed that compared with the control group, the mRNA levels of IL-6, IL-1β and TNF-α (all P<0.05) in oxygen-glucose deprivation/reoxygenation group were significantly higher than those of the control group.And the mRNA levels of IL-1β, IL-6 and TNF-α in oxygen-glucose deprivation/reoxygenation + 0.05 μmol/L ART group, oxygen-glucose deprivation/reoxygenation + 0.1 μmol/L ART group and oxygen-glucose deprivation/reoxygenation + 0.5 μmol/L ART group were significantly lower than those of the oxygen-glucose deprivation/reoxygenation group (all P<0.05). Western blot results showed that compared with the control group, the expression of CD206 ((0.85±0.04), (1.07±0.07), P<0.05) was significantly down-regulated in the oxygen-glucose deprivation/reoxygenation group.The CD206 and ARG in oxygen-glucose deprivation/reoxygenation + 0.1 μmol/L ART group((1.22±0.06), (1.35±0.08)) and oxygen-glucose deprivation/reoxygenation + 0.5 μmol/L ART group((1.24±0.14), (1.14±0.07)) were significantly higer than those of oxygen-glucose deprivation/reoxygenation group((0.85±0.04), (0.85±0.05))(all P<0.05). The results of CCK8 showed that compared with the control group, the cell viability in the oxygen-glucose deprivation/reoxygenation group was significantly decreased( P<0.05). The cell viability of the oxygen-glucose deprivation/reoxygenation + 0.05 μmol/L ART group, the oxygen-glucose deprivation/reoxygenation + 0.1 μmol/L ART group, the oxygen-glucose deprivation/reoxygenation + 0.5 μmol/L ART group were all higher than those of oxygen-glucose deprivation/reoxygenation group(all P<0.05). Conclusion:ART reduces neuronal apoptosis after stroke, decreases the neuroinflammatory response after stroke, and promotes oxygen-glucose deprivation/reoxygenation-activated microglia BV2 polarization to the M2 type.
ABSTRACT
Objective To evaluate the effect of hypoxic-ischemic time on reduction of hypoxic-ischemic brain injury by sevoflurane postconditioning in neonatal rats.Methods Two hundred and ten 7-day-old Sprague-Dawley rats (105 male,105 female),weighing 13-17 g,were randomly divided into 7groups (n=30 each) using a random number table:sham operation group (group Sham),hypoxia-ischemia group (group HI),and sevoflurane postconditioning at different hypoxic-ischemic time point groups (P0,P3,P6,P 12 and P24 groups).Immediately after ligation of the left common carotid artery,and at 3,6,12 and 24 h after ligation,the rats inhaled the mixed gas containing 2％ sevoflurane for 30 min in P0,P3,P6,P13 and P24 groups,respectively.The fatality was recorded within 7 days after establishment of the model.At 7 days after establishment of the model,the rats were sacrificed,the brains were removed,and the right and left cerebral hemispheres were weighed separately,and the left/right cerebral hemisphere weight ratio was calculated.The hippocampal CA1 region and posterior cingulate gyrus were isolated,and the ratio of density of normal neurons in the left to the right was calculated.Results Compared with group Sham,the left cerebral hemisphere weight,left/right cerebral hemisphere weight ratio,and ratio of density of normal neurons were significantly decreased,and the fatality rate was increased in the other six groups (P＜0.05).Compared with group HI,the left cerebral hemisphere weight,left/right cerebral hemisphere weight ratio,and ratio of density of normal ncurons were significantly increased in P0,P3 and P6 groups (P＜0.05),and no significant change was found in the parameters mentioned above in P12 and P24 groups (P＞0.05).Compared with group P6,the left cerebral hemisphere weight,left/right cerebral hemisphere weight ratio,and ratio of density of normal neurons were significantly increased in P0 and P3 groups (P＜ 0.05).There was no significant difference in the parameters mentioned above between group P0 and group P3 (P＞0.05).Conclusion Sevoflurane postconditioning performed within 6 h of hypoxia-ischemia can reduce hypoxic-ischemic brain injury,and it provides no cerebral protection if exceeding 12 h.