Résumé
Objective:To explore the role of hippocampal γ oscillation abnormality in sepsis-associated encephalopathy (SAE).Methods:Seventy male Sprague-Dawley rats (2-3 months) were randomly (random number) divided into three groups according to the random digital table method: sham, CLP, and CLP + dopamine 4 (D4) receptor agonists RO-10-5824 group. The SAE animal model was established by cecal ligation and puncture (CLP). On day 10-14 after surgery, the open field, novel object recognition, and fear conditioning tests were performed. After that, the hippocampus was collected to measure expressions of parvalbumin (PV) and D4 receptor. In another set of experiment, CA1 local field potential (LFP) were recorded, and the relationship between LFP and time with novel object was analyzed. Independent sample t-test was used for pairwise comparisons, and multiple comparisons were performed by one-way ANOVA, followed by the Tukey multiple comparisons test. Correlation was analyzed using Pearson correlation. Statistical significance was assumed when P<0.05. Results:Compared with the sham group, hippocampal PV (77.54±4.61)%, D4 expression (56.36±3.88)% and γ oscillation power (41.1±8.62)%, object exposure time (36±3) s, new object recognition rate (49±4)%, and scene stiffness time (56±7) s were decreased significantly ( P<0.05). However, RO-10-5824 treatment could increase hippocaml γ oscillation power (92.3±6.7)%, and reverse the decreased new object exposure time (44±3) s and new object recognition rate (63±4)%. Correlation analysis showed that hippocampal γ oscillation power was positively associated with new object exposure time ( r=0.609 2, P=0.015 9). There was no difference in total distance traveled or time spent in the center among groups ( P>0.05). Conclusion:Hippocampal γ oscillation abnormality might play a key role in cognitive impairment associated with SAE.