Astragaloside inhibits astrocyte activation and inflammatory response induced by inflammation / 中国组织工程研究

BACKGROUND:Astrocytes play an important role in the pathology of central nervous system diseases.The phenotypic and functional changes in astrocytes suggest that it may be an effective therapeutic target for central nervous system diseases.Our previous studies have confirmed that astragaloside can inhibit the lipopolysaccharide-induced astrocyte inflammatory response.Whether astragaloside can regulate the phenotype and function of astrocytes through Notch-1 and its downstream signaling pathway remains unclear. OBJECTIVE:To explore the effect of astragaloside on astrocyte activation and inflammatory response induced by inflammation and its possible mechanism. METHODS:Cerebral cortex astrocytes derived from neonatal C57BL/6 mouse were cultured in vitro.CCK-8 assay was used to determine the optimum concentration of astragaloside and Notch active inhibitor DAPT.The astrocytes were divided into five groups:PBS group,lipopolysaccharide group,lipopolysaccharide + astragaloside group,lipopolysaccharide + DAPT group and lipopolysaccharide + DAPT + astragaloside group.The secretion level of inflammatory factors was detected by ELISA,and the level of nitric oxide was detected by Griess method.The astrocytes and splenic mononuclear cells were co-cultured in Transwell chamber to observe the migration of CD4T cells.The expression of astrocyte activation marker GFAP,A1 marker C3 and A2 marker S100A10 as well as Notch 1 and Jag-1 was detected by immunofluorescence staining.The expressions of CFB,C3,S100A10,PTX3,Notch-1,Jag-1,and Hes were detected by western blot assay. RESULTS AND CONCLUSION:(1)According to the results of CCK8 assay,the final concentration of astragaloside was selected as 25 μmol/L and the final concentration of DAPT was 50 μmol/L for follow-up experiments.(2)Compared with PBS group,interleukin-6,interleukin-12 and nitric oxide secretion levels in the lipopolysaccharide group were significantly increased(P<0.05,P<0.05,P<0.01).Compared with the lipopolysaccharide group,interleukin-6(all P<0.05),interleukin-12(P>0.05,P<0.05,P<0.05)and nitric oxide(P<0.05,P<0.01,P<0.01)secretion significantly reduced in the lipopolysaccharide + astragaloside group,lipopolysaccharide +DAPT group,lipopolysaccharide + DAPT + astragaloside group.(3)Compared with the PBS group,the expression of GFAP that is the marker of activated astrocytes and the migration of CD4 T cells were significantly increased in the lipopolysaccharide group(P<0.01).Compared with the lipopolysaccharide group,astrocyte activation was significantly inhibited and CD4 T cell migration was significantly reduced in the lipopolysaccharide + astragaloside,lipopolysaccharide +DAPT,lipopolysaccharide + DAPT + astragaloside group(P<0.05,P<0.05,P<0.01).(4)Compared with the PBS group,the expressions of A1 markers C3 and CFB in the lipopolysaccharide group were increased(P<0.01,P<0.05),and the expressions of A2 markers S100A10 and PTX3 were decreased(P<0.01,P<0.05).Compared with the lipopolysaccharide group,C3(all P<0.01)and CFB(both P<0.05)were significantly reduced and S100A10(all P<0.01)and PTX3(P<0.05,P<0.05 and P>0.05)were increased in the lipopolysaccharide + astragaloside,lipopolysaccharide +DAPT,lipopolysaccharide + DAPT + astragaloside group.(5)Compared with the PBS group,the expressions of Jag-1,Notch-1 and Hes in the lipopolysaccharide group were significantly increased(all P<0.01).Compared with the lipopolysaccharide group,the expressions of Jag-1(all P<0.01),Notch-1(all P<0.01)and Hes(P<0.05,P<0.01 and P<0.01)were significantly reduced in the lipopolysaccharide + astragaloside,lipopolysaccharide +DAPT,lipopolysaccharide + DAPT + astragaloside group.(6)The results indicate that astragaloside can promote the transformation of astrocytes from A1 to A2 by regulating Notch-1 signaling pathway,reduce the secretion of inflammatory factors and the migration of CD4 T cells,and thus inhibit astrocyte activation and inflammatory response.

Effects and mechanisms of melatonin combined with enriched environment on learning and memory ability of SAMP8 mice / 中华行为医学与脑科学杂志

Objective:To explore the effects and possible mechanisms of melatonin combined with enriched environment on the learning and memory ability of senescence-accelerated mouse prone 8(SAMP8).Methods:Forty-eight SAMP8 male mice aged 4 months were randomly divided into model group, enriched environment group, melatonin group and melatonin combined with enriched environment group (combined intervention group) by random number table method, with 12 mice in each group. Mice in the melatonin group and combined intervention group were subcutaneously injected with melatonin at a dose of 8 mg·kg -1·d -1, and the mice in the model group and the enriched environment group were given the same amount of normal saline instead.The mice in model group and melatonin group were raised in a standard environment, and the mice in enriched environment group and combined intervention group were raised in an enriched environment.The intervention lasted 28 days. The aging degree of mice was scored before and 28 days after the intervention. Morris water maze test was used to detect the learning and memory ability of mice. Nissl staining and TUNEL staining were used to observe the Nissl staining positive cells and apoptotic cells in the CA1 area of hippocampus.ELISA was used to detect the levels of interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in the hippocampus of mice. Western blot was used to detect the levels of amyloid β-protein (Aβ) 1-42, microtubule-associated protein tau (tau) phosphorylated at threonine (Thr) 205 (Tau pT205), Toll-like receptor 4 (TLR4), and nuclear factor-κB (NF-κB) p65 protein in the hippocampus of mice. qRT-PCR was used to detect the levels of TLR4, NF-κB p65 mRNA in the hippocampus of mice. SPSS 22. 0 statistical software was used for repeated measure ANOVA, one-way ANOVA and LSD test. Results:(1) Aging score: after intervention, the aging scores of mice in the four groups were significantly different ( F=120.601, P<0.01). The aging scores of mice in the enriched environment group, melatonin group, and combined intervention group were lower than those in the model group (all P<0.05), while the aging score of mice in the combined intervention group was significantly lower than those in the enriched environment group and melatonin group (both P<0.05). (2) The results of the location navigation experiment showed that the time × group interaction effect of the escape latencies of mice in the four groups were significant ( F=30.524, P<0.001). From the 2nd to 4th day, the escape latencies of mice in the enriched environment group, melatonin group and combined intervention group were all lower than that in the model group (all P<0.05). The results of the space exploration experiment showed that the residence time in the target quadrant and the number of platform crossings of mice in the four groups were significantly different ( F=291.328, 113.482, both P<0.01). The residence time in the target quadrant ((29.45±1.70)s, (32.44±1.55)s, (37.48±0.84) s) and the number of platform crossings ((6.44±0.61) times, (7.16±0.70) times, (12.60±1.23) times) of mice in the enriched environment group, melatonin group and combined intervention group were higher than those in the model group ((15.07±1.28) s, (4.10±0.61) times), while the residence time in the target quadrant and the number of platform crossings of mice in the enriched environment group and the melatonin group were significantly lower than those in the combined intervention group (all P<0.05). (3) Nissl and TUNEL staining showed that the number of Nissl positive neurons in the hippocampal CA1 region of mice in the four groups were significantly different ( F=809.264, P<0.01), and the number of apoptotic cells in the hippocampal CA1 region were also significantly different ( F=1 060.583, P<0.01). The number of Nissl stained positive neurons in the hippocampal CA1 region of mice in the combined intervention group was more than those in the model group, enriched environment group, and melatonin group (all P<0.05), and the number of apoptotic cells were less than those in the model group, enriched environment group, and melatonin group (all P<0.05). (4) The results of ELISA assay showed that there were significantly different in the levels of IL-1β, IL-6 and TNF-α in the hippocampus of mice in the four groups ( F=152.887, 63.506, 432.026, all P<0.01). The contents of IL-1β, IL-6 and TNF-α in the hippocampus of mice in the enriched environment group, melatonin group, and combined intervention group were lower than those in the model group(all P<0.05). Among them, the contents of IL-1β, IL-6 and TNF-α in the hippocampus of mice in the enriched environment group and melatonin group were significantly higher than those in the combined intervention group (all P<0.05). (5) Western blot analysis showed that there were significantly different in the protein expression levels of Aβ1~42, tau pT205, TLR4, NF-κB p65 in the hippocampus of mice in the four groups ( F=122.349, 98.934, 201.635, 116.553, all P<0.01). The protein expression levels of Aβ1-42, tau pT205, TLR4, and NF-κB p65 in the hippocampus of mice in the enriched environment group, melatonin group, and combined intervention group were lower than those in the model group.Among them, the protein expression levels of Aβ1-42, tau pT205, TLR4, NF-κB p65 in the hippocampus of mice in the enriched environment group and melatonin group were significantly higher than those in the combined intervention group (all P<0.05). (6) qRT-PCR showed that the mRNA expression levels of TLR4 and NF-κB p65 in the hippocampus of mice in the four groups were significantly different ( F=42.913, 102.446, both P<0.01). The mRNA expression levels of TLR4 ((0.63±0.05), (0.55±0.04), (0.42±0.03)) and NF-κB p65 ((0.98±0.06), (0.82±0.04), (0.72±0.04)) in the hippocampus of mice in the enriched environment group, melatonin group and combined intervention group were lower than those in the model group ((0.74±0.07), (1.20±0.05)) (all P<0.05). Among them, the mRNA expression levels of TLR4 and NF-κB p65 in the hippocampus of mice in the enriched environment group and melatonin group were significantly higher than those in the combined intervention group (all P<0.05). Conclusion:Melatonin combined with enriched environment can improve the learning and memory ability and neuroinflammatory response of SAMP8 mice, and its mechanism may be related with the down-regulation of TLR4/NF-κB p65 signaling pathway.

Micro RNA-193b-3p inhibits neuro-inflammatory response in neonatal sepsis rats by targeting retinoic acid receptor-related orphan receptor α / 中华神经医学杂志

Objective:To explore the micro RNA (miR)-193b-3p expression in hippocampus tissues of neonatal sepsis rats, as well as its role in neuroinflammatory response and possible mechanisms.Methods:Twenty-four 2-d-old SD rats were randomly divided into control group, lipopolysaccharide (LPS) group, negative control group, and miR-193b-3p group ( n=6); except for the negative control group, the rats in the other 3 groups were intraperitoneally injected with LPS to establish sepsis models; in miR-193b-3p group and NC group, 5 μL miR-193b-3p mimics/controls (20 nmol/L)were injected into the lateral ventricle 3 d before LPS injection. In vitro, PC12 cells were divided into control group, LPS group, miR-193b-3p group, and LPS+miR-193b-3p group; miR-193b-3p mimics were transfected into cells of miR-193b-3p group and LPS+miR-193b-3p group; cells in the LPS group and LPS+miR-193b-3p group were exposed to 100 ng/mL LPS. The miR-193b-3p downstream target gene was analyzed by gene microarray and dual luciferase reporter. Neurobehavioral scale used to assess the neurological function at specific time points in each group. The mRNA expression levels of miR-193b-3p and cytokines (interleukin [IL]-1β, IL-6, tumor necrosis factor [TNF]-α) in the brain tissues or PC12 cells were analyzed by real-time fluorescence quantification PCR (RT-qPCR). The protein expression levels of retinoic acid-related orphan receptor α (RORα), neuronal nuclear antigen (NeuN), ionized calcium binding adaptor molecule-1 (IBA-1) and glial fibrillary acidic protein (GFAP) were detected by double-labelling immunofluorescence. The protein expression levels of RORα in PC12 cells were detected by immunofluorescence staining. Results:(1) Gene microarray and dual luciferase reporter analysis confirmed that RORα was the target gene of miR-193b-3p. (2) As compared with those in rats of the negative control group, the neurobehavioral scores in rats of the LPS group were significantly decreased since 6 h of LPS injection and reached to the lowest at 24 h after LPS ( P<0.05). As compared with those in the negative control group, the IL-1β, IL-6, and TNF-α mRNA expression levels in the hippocampus of LPS group were significantly increased, while the miR-193b-3p expression was significantly decreased ( P<0.05). (3) As compared with those in negative control group (3.23±0.92), the neurobehavioral scores in rats of the miR-193b-3p group (7.51±0.84) 48 h after LPS injection were significantly higher ( P<0.05). As compared with those in the negative control group, the IL-1β, IL-6 and TNF-α mRNA expression levels in the hippocampus of the miR-193b-3p group were significantly deceased, while the miR-193b-3p expression was significantly higher ( P<0.05). (4) As compared with that in negative control group, the number of NeuN(+)RORα(+) cells in the hippocampus of the LPS group was significantly reduced ( P<0.05); as compared with negative control group, miR-193b-3p group had significantly increased number of NeuN(+)RORα(+) cells in the hippocampus ( P<0.05). (5) As compared with the control group, the LPS group had significantly decreased RORα expression, and significantly increased TNF-α, IL-1β and IL-6 mRNA expression in PC12 cells ( P<0.05). As compared with those in the LPS group, the RORα expression was significantly increased, and the TNF-α, IL-1β and IL-6 mRNA expression levels in PC12 cells were significantly decreased in LPS+miR-193b-3p group ( P<0.05). Conclusion:The miR-193b-3p inhibits the neuroinflammatory response in neonatal sepsis rats by regulating its target molecule RORα mRNA expression in hippocampal neurocyte.