RESUMO
Objective:To investigate the icariin on cognitive function and astrocytic pyroptosis in hemorrhagic shock resuscitation model mice.Methods:Forty-eight SPF grade C57BL/6 mice (male) were randomly divided into four groups ( n=12 in each group): Sham operation control group (Group C), hemorrhagic shock and resuscitation group (Group H), hemorrhagic shock and resuscitation plus icariin group (Group HI) and hemorrhagic shock resuscitation plus icariin and SSK1 group (Group HIS, SSK1 was a phosphorylation agonist of mitogen-activated protein kinase p38(p38MAPK). The mice in Group H, HI and HIS were subjected to hemorrhagic shock and resuscitation model by bleeding and retransfusion via left femoral vein; the mice in Group HI and HIS were administered with icariin (10 mg/kg) intragastrically for 7 days; the mice in Group C and H were administered with the same amount of normal saline containing dimethyl sulfoxide(DMSO). The mice in Group HIS were administered with SSK1 (0.5 mg/kg) intraperitoneally, but the mice in Group C, H and HI were only administered with the same amount of normal saline containing DMSO.At 15 days after resuscitation, novel objective recognition test and fear conditioning test were used to assess cognitive dysfunction of mice.Microtubule-associated protein 2(MAP2), a specific marker protein of neurons reflecting astrocytic pyroptosis in the hippocampus of mice, were detected by immunofluorescence assay so as to assess neuronal injury and astrocytic pyroptosis.The levels of IL-1β, IL-18, the ratio of phosphorylated p38MAPK to total p38MAPK in the hippocampus were evaluated by Western blot.SPSS 21.0 software was used for data analysis, multiple samples among groups were compared by one-way ANOVA, and SNK- q test was used for further pairwise comparison. Results:The results of new object recognition test showed that the difference of new object recognition index among the four groups was statistically significant ( F=50.75, P<0.05). The new object recognition indexes in H group(22.7±6.9), HI group(40.1±7.0) and HIS group (22.5±7.5) were significantly lower than that in C group (58.5±11.2). The index in HI group was higher than that in H group, while the index in HIS group was lower than that in HI group (all P<0.05). The results of the fear conditioning test showed that there was a statistically significant difference in the percentage of freezing time among the four groups of mice ( F=60.54, P<0.05). And the percentage of freezing time in H group((21.8±5.0)%), HI group ((38.4±7.4) %)and HIS group((21.3±4.2)%)were lower than that in C group((49.1±7.0)%), which in HI group was higher than that in H group ( P<0.05)and which in HIS group was lower than that in HI group(all P<0.05). The results of immunofluorescence showed that there were significant decreases of MAP2 intensity ((35.3±9.3)%, (63.3±6.1)%, (28.7±10.3)%) but increases of pyroptotic astrocytes ((24.5±4.2)%, (9.3±1.5)%, (22.1±3.3)%) in the H, HI and HIS groups compared with those of C group ((106.7±19.7) %, (3.4±2.0)%). There was an increase of MAP2 intensity but a decrease of pyroptotic astrocytes in the HI group compared with those in H group, and there was a decrease of MAP2 intensity but an increase of pyroptotic astrocytes in the HIS group compared with those of HI group (all P<0.05). The Western blot results showed that there were significant increases of IL-1β, IL-18, the ratio of phosphorylated p38MAPK to total p38MAPK in the H, HI and HIS groups compared with C group, there were decreases of IL-1β, IL-18, the ratio of phosphorylated p38MAPK to total p38MAPK in the HI group compared with H group, and there were increases of IL-1β, IL-18, the ratio of phosphorylated p38MAPK to total p38MAPK in the HIS group compared with those in HI group (all P<0.05). Conclusion:Icariin alleviates hemorrhage shock and resuscitation-induced cognitive dysfunction and astrocytic pyroptosis in mice, and the mechanism may be associated with inhibition of phosphorylated p38MAPK.