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Background Stroke is a cardiovascular disease that seriously endangers human health, which is characterized by high prevalence, disability and mortality rates. Peony bark is the dried root bark of peony in the buttercup family, which has the effect of clearing heat and cooling blood, activating blood circulation and resolving blood stasis. Paeonol (PAE) is the main active ingredient of peony bark, has been confirmed to have neuroprotective effect under hypoglycemia and hypoxia conditions. Objective To observe the effect and neurobiological mechanism of gastric administration of paeonol solution on improving behavioral dysfunction caused by middle cerebral artery occlusion (MCAO) , a kind of stroke, in a mouse model. Methods The study was conducted from December 2019 to December 2021. Twenty SPF male C57BL/6 mice were randomized into SHAM group (n=10) and model group (MCAO group, n=10) . The MCAO model was formed by intraluminal suture method. After 24 hours of modeling, the neurological function of each group was evaluated by Longa Score. Laser Speckle Contrast Imaging was used to monitor the changes of cerebral blood flow after MCAO. TTC staining was used in the pathological examination of cerebral infarction in MCAO mice. For investigating the protective effect of PAE on behavioural dysfunction of MCAO mice, 50 SPF male C57BL/6 mice were randomly grouped into SHAM group (n=10) , model+corn oil group (n=20) , and model+PAE group (n=20) . After the verification of model stability at 24 hours following the modeling, the model+PAE group received intragastric administration of PAE and corn oil solution in a concentration of 100 mg·kg-1· d-1, and the other two groups were gavaged with equal amounts of corn oil. Then on the 28th day after of modelling, survival curve was plotted to assess the survival status of mice in the three groups; the neurological recovery of mice was determined using the Longa Score; the area of cerebral infarction was examined by Nissl staining. The behavioural changes in motor sensory function were tested at five time points: the day before modeling, and 7, 14, 21 and 28 days after modelling. For exploring the mechanism of PAE improving behavioural dysfunction in MCAO mice, 30 SPF male C57BL/6 mice were randomly divided into SHAM group (n=6) , model+corn oil group (n=12) and model+PAE group (n=12) . After verifying the model stability at 24 hours following the modeling, the model+PAE group received intragastric administration of PAE and corn oil solution in a concentration of 100 mg·kg-1· d-1, and the other two groups were gavaged with an equal amount of corn oil. The expression of interleukin 1β (IL-1β) protein in the striatum of mouse brain was measured by Western blotting on the second day after modelling to investigate whether PAE could reduce the inflammatory response in the brain during the acute period. The expression of ionized calcium-binding adapter molecule 1 (IBA1) and glial fibrillary acidic protein (GFAP) in the penumbra was measured by immunofluorescence on the 14th day after modelling. Results The 28-day survival rate was 66.47% for the model+corn oil group, and 81.43% for model+PAE group. Log-rank test showed that the 28-day survival curve significantly differed across SHAM group, model+corn oil group, and model+PAE group (χ2=1.436, P |
